Fill missing Spanish (es) translations for feature + UI strings

Add es localizations for the 138 string keys that had an en entry but no
es entry, so Spanish-language devices no longer render raw dot-keys.
Covers bulletin/legend, network topology, groups, gateway, media/image,
voice notes, delivery, payment, vouching, and mesh system messages.
Format specifiers, plural substitutions, punctuation, and the app's
lowercase aesthetic are preserved.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitattributes

@@ -0,0 +1,20 @@
+# Prevent Github Languages stats skewing:
+
+# Binaries and assets
+**/*.xcframework/** linguist-vendored
+**/*.xcassets/** linguist-vendored
+
+# Generated files
+**/*.pbxproj linguist-generated
+**/*.storyboard linguist-generated
+Package.resolved linguist-generated
+
+# Downloaded CSVs
+relays/online_relays_gps.csv linguist-vendored
+
+# Docs
+**/*.md linguist-documentation
+
+# Configs
+Configs/*.xcconfig linguist-documentation
+**/*.plist linguist-documentation

.github/workflows/arti-provenance.yml

@@ -0,0 +1,85 @@
+name: Arti Binary Provenance
+
+# The Arti xcframework is a vendored binary; these checks turn the policy in
+# docs/ARTI-BINARY-PROVENANCE.md into an enforced gate:
+#  1. The checked-in binary must match the hash manifest in the provenance doc.
+#  2. A PR that changes the binary must also change at least one provenance
+#     input (Rust source, lockfile, build script, or the doc itself).
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - "localPackages/Arti/**"
+      - "docs/ARTI-BINARY-PROVENANCE.md"
+  pull_request:
+    paths:
+      - "localPackages/Arti/**"
+      - "docs/ARTI-BINARY-PROVENANCE.md"
+
+jobs:
+  verify-hashes:
+    name: Verify xcframework hashes against provenance doc
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v5
+
+      - name: Compare artifact hashes with manifest
+        run: |
+          set -euo pipefail
+          doc="docs/ARTI-BINARY-PROVENANCE.md"
+
+          # Extract the manifest: lines of "<sha256>  <path>" from the doc.
+          grep -E '^[0-9a-f]{64}  localPackages/Arti/Frameworks/arti\.xcframework/' "$doc" \
+            | sort -k2 > expected.txt
+
+          if [ ! -s expected.txt ]; then
+            echo "::error::No hash manifest found in $doc"
+            exit 1
+          fi
+
+          # Hash the same file set the doc documents.
+          find localPackages/Arti/Frameworks/arti.xcframework -maxdepth 3 -type f -print0 \
+            | sort -z | xargs -0 sha256sum | sed 's/  \.\//  /' | sort -k2 > actual.txt
+
+          if ! diff -u expected.txt actual.txt; then
+            echo "::error::Checked-in arti.xcframework does not match the manifest in $doc. If the binary change is intentional, rebuild per the doc and update the manifest in the same PR."
+            exit 1
+          fi
+          echo "All $(wc -l < actual.txt) artifact hashes match the provenance manifest."
+
+  require-provenance-evidence:
+    name: Binary changes must ship with provenance inputs
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request'
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v5
+        with:
+          fetch-depth: 0
+
+      - name: Check changed files
+        run: |
+          set -euo pipefail
+          base="origin/${{ github.base_ref }}"
+          git fetch --no-tags --depth=1 origin "${{ github.base_ref }}"
+          changed=$(git diff --name-only "$base"...HEAD)
+          echo "Changed files:"
+          echo "$changed"
+
+          if ! echo "$changed" | grep -q '^localPackages/Arti/Frameworks/arti\.xcframework/'; then
+            echo "No binary artifact changes; nothing to verify."
+            exit 0
+          fi
+
+          if echo "$changed" | grep -Eq '^(localPackages/Arti/(Cargo\.(toml|lock)|build-ios\.sh|arti-bitchat/)|docs/ARTI-BINARY-PROVENANCE\.md)'; then
+            echo "Binary change is accompanied by provenance inputs."
+            exit 0
+          fi
+
+          echo "::error::arti.xcframework changed without matching source, lockfile, build-script, or provenance-doc changes. See docs/ARTI-BINARY-PROVENANCE.md (\"Do not accept an xcframework-only update\")."
+          exit 1

.github/workflows/fetch_georelays.yml

@@ -0,0 +1,42 @@
+name: Fetch GeoRelays Data
+
+on:
+  schedule:
+    - cron: '0 6 * * 0'
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  update-relay-data:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          fetch-depth: 0
+
+      - name: Fetch GeoRelays
+        run: |
+          wget -q https://raw.githubusercontent.com/permissionlesstech/georelays/refs/heads/main/nostr_relays.csv
+          mv nostr_relays.csv ./relays/online_relays_gps.csv
+
+      - name: Check for changes
+        id: git-check
+        run: |
+          git diff --exit-code || echo "changes=true" >> $GITHUB_OUTPUT
+    
+      - name: Commit and push changes
+        if: steps.git-check.outputs.changes == 'true'
+        run: |
+          git config --local user.email "action@github.com"
+          git config --local user.name "GitHub Action"
+          git add relays/online_relays_gps.csv
+          git commit -m "Automated update of relay data - $(date -u)"
+          git push
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/swift-tests.yml

@@ -0,0 +1,179 @@
+name: Build & Test
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  test:
+    name: Run Swift Tests (${{ matrix.name }})
+    runs-on: macos-latest
+    # A hung test must fail fast, not hold a runner for GitHub's 360-minute
+    # default (observed: intermittent app-suite hangs starving the queue).
+    # The long steps carry tighter individual bounds (5-minute test watchdog,
+    # 6-minute benchmark step, 10-minute floor gate that may re-run the
+    # benchmarks up to twice on a noisy runner); this is the backstop.
+    timeout-minutes: 25
+
+    strategy:
+      fail-fast: false # Don't cancel other matrix jobs when one fails
+      matrix:
+        include:
+          - name: app
+            path: .
+          - name: BitLogger
+            path: localPackages/BitLogger
+          - name: BitFoundation
+            path: localPackages/BitFoundation
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v5
+
+      # Use the Xcode-bundled Swift toolchain: it always matches the SDK on
+      # the runner image. A standalone swift.org toolchain (setup-swift) broke
+      # whenever the image's Xcode moved ahead of it ("this SDK is not
+      # supported by the compiler").
+      - name: Note toolchain version (cache key)
+        id: swift-version
+        run: echo "version=$(swift --version 2>/dev/null | head -1 | shasum | cut -c1-12)" >> "$GITHUB_OUTPUT"
+
+      - name: Cache build artifacts
+        uses: actions/cache@v4
+        with:
+          path: ${{ matrix.path }}/.build
+          key: ${{ runner.os }}-${{ steps.swift-version.outputs.version }}-${{ matrix.name }}-${{ hashFiles(format('{0}/**/*.swift', matrix.path), format('{0}/**/Package.resolved', matrix.path)) }}
+          restore-keys: |
+            ${{ runner.os }}-${{ steps.swift-version.outputs.version }}-${{ matrix.name }}-${{ hashFiles(format('{0}/**/Package.resolved', matrix.path)) }}
+            ${{ runner.os }}-${{ steps.swift-version.outputs.version }}-${{ matrix.name }}-
+
+      - name: Build tests
+        # Built separately so the hang watchdog below times only test
+        # execution: a cold-cache coverage build on a slow runner can
+        # legitimately take several minutes, and is already bounded by the
+        # 15-minute job timeout.
+        run: swift build --build-tests --enable-code-coverage --package-path ${{ matrix.path }}
+
+      - name: Run Tests
+        # Perf benchmarks are excluded here and run in their own serial step
+        # below: measuring while parallel test processes contend for cores
+        # produces noisy numbers, and the XCTest measure machinery has hung
+        # intermittently under parallel workers on loaded runners. Excluded
+        # via --skip (not just the env guard): every app run since the
+        # baselines landed timed out at the 15-minute job limit with the
+        # baseline tests dispatched into the parallel phase.
+        #
+        # The watchdog samples any still-running test processes after 5
+        # minutes (the suite passes in seconds when healthy; the build is
+        # done by this step) and kills the run, so a hang fails fast with
+        # stacks in the log instead of a silent timeout.
+        env:
+          BITCHAT_SKIP_PERF_BASELINES: "1"
+        run: |
+          swift test --skip-build --parallel --quiet --enable-code-coverage \
+            --skip PerformanceBaselineTests \
+            --package-path ${{ matrix.path }} &
+          test_pid=$!
+          (
+            sleep 300
+            if kill -0 "$test_pid" 2>/dev/null; then
+              echo "::group::Tests still running after 5 minutes — sampling before kill"
+              for pid in $(pgrep -if 'swiftpm-testing|xctest|PackageTests' || true); do
+                echo "--- sample of pid $pid ---"
+                sample "$pid" 5 2>/dev/null || true
+              done
+              echo "::endgroup::"
+              pkill -KILL -P "$test_pid" 2>/dev/null || true
+              kill -KILL "$test_pid" 2>/dev/null || true
+            fi
+          ) &
+          watchdog_pid=$!
+          wait "$test_pid" && status=0 || status=$?
+          kill "$watchdog_pid" 2>/dev/null || true
+          exit "$status"
+
+      # Benchmarks run serially on an otherwise idle runner for stable
+      # numbers; BITCHAT_PERF_LOG captures the PERF[...] lines for the gate.
+      - name: Run performance benchmarks (serial)
+        if: matrix.name == 'app'
+        timeout-minutes: 6
+        env:
+          BITCHAT_PERF_LOG: ${{ github.workspace }}/perf-output.log
+        run: swift test --quiet --filter PerformanceBaselineTests
+
+      # Order-of-magnitude performance regression gate. Floors are deliberately
+      # generous (see bitchatTests/Performance/perf-floors.json) so this
+      # catches algorithmic regressions, never runner variance. If a metric
+      # still lands below floor (a saturated runner can dip one), the script
+      # re-runs the benchmarks — appending to the same log and keeping each
+      # benchmark's best value per metric — so noise clears on retry while a
+      # real regression fails every attempt. Floors are never lowered by this.
+      - name: Performance floor gate
+        if: matrix.name == 'app'
+        timeout-minutes: 10
+        run: ./scripts/check-perf-floors.sh perf-output.log
+
+      # Informational only: surfaces per-file and total line coverage in the
+      # job log so coverage trends are visible on every PR. No thresholds —
+      # this must never be the reason a build goes red.
+      - name: Coverage summary
+        run: |
+          BIN_PATH=$(swift build --show-bin-path --package-path ${{ matrix.path }})
+          PROF="$BIN_PATH/codecov/default.profdata"
+          XCTEST=$(find "$BIN_PATH" -maxdepth 1 -name '*.xctest' | head -1)
+          BINARY="$XCTEST/Contents/MacOS/$(basename "$XCTEST" .xctest)"
+          if [ -f "$PROF" ] && [ -f "$BINARY" ]; then
+            xcrun llvm-cov report "$BINARY" -instr-profile "$PROF" \
+              -ignore-filename-regex='(Tests|\.build|checkouts|Mocks|_PreviewHelpers)' || true
+          else
+            echo "No coverage data found; skipping summary."
+          fi
+
+  # SPM tests above only compile the macOS slice; this job covers the
+  # iOS-conditional code paths (UIKit, CoreBluetooth restoration, etc.).
+  ios-build:
+    name: Build iOS app (simulator)
+    runs-on: macos-latest
+    timeout-minutes: 15
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v5
+
+      - name: Build iOS (simulator, no signing)
+        # arm64 only: the vendored arti.xcframework has no x86_64 simulator slice.
+        run: |
+          set -o pipefail
+          xcodebuild -project bitchat.xcodeproj \
+            -scheme "bitchat (iOS)" \
+            -sdk iphonesimulator \
+            -destination 'generic/platform=iOS Simulator' \
+            ARCHS=arm64 \
+            CODE_SIGNING_ALLOWED=NO \
+            build
+
+  # Advisory only: SwiftLint reports style violations without ever failing the
+  # build. Runs in a pinned container (no Xcode plugin, no pbxproj changes) so
+  # it can never break the documented xcodebuild path or block a merge.
+  lint:
+    name: SwiftLint (advisory)
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    # This job runs a third-party container image, so give it the least
+    # privilege we can: a read-only token, and no credentials left in the
+    # checkout for the container to find.
+    permissions:
+      contents: read
+    container:
+      # Tag for readability, digest for immutability (tags can be repointed).
+      # Bump both together, deliberately — never a floating tag.
+      image: ghcr.io/realm/swiftlint:0.65.0@sha256:a482729f4b58741875af1566f23397f3f6db300372756fc31606d0a4527fab9e
+    continue-on-error: true
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          persist-credentials: false
+      - name: Run SwiftLint
+        run: swiftlint lint --reporter github-actions-logging

.gitignore

@@ -5,8 +5,10 @@
 ## implementation plans
 plans/
 
-## User settings
-xcuserdata/
+## AI
+CLAUDE.md
+AGENTS.md
+.claude/
 
 ## compatibility with Xcode 8 and earlier (ignoring not required starting Xcode 9)
 *.xcscmblueprint
@@ -15,6 +17,7 @@ xcuserdata/
 ## compatibility with Xcode 3 and earlier (ignoring not required starting Xcode 4)
 build/
 DerivedData/
+.DerivedData/
 *.moved-aside
 *.pbxuser
 !default.pbxuser
@@ -52,7 +55,8 @@ iOSInjectionProject/
 
 ## Xcode project
 *.xcodeproj/project.xcworkspace/
-*.xcodeproj/xcshareddata/
+## Xcode User settings
+xcuserdata/
 
 ## Python
 __pycache__/
@@ -62,3 +66,17 @@ __pycache__/
 ## Temporary files
 *.tmp
 *.temp
+
+## Cache
+.cache/
+
+# Local build results
+.Result*/
+.Result*.xcresult/
+TestResult.xcresult/
+*.xcresult/
+build.log
+*.log
+
+# Local configs
+Local.xcconfig

.swiftlint.yml

@@ -0,0 +1,33 @@
+# Build artifacts and generated sources; keeps local `swiftlint` runs clean
+# (CI checkouts are fresh, so this only matters in a working tree).
+excluded:
+  - .build
+  - .swiftpm
+  - .DerivedData
+  - DerivedData
+  - build
+  - localPackages/*/.build
+
+disabled_rules:
+  - line_length
+  - type_name
+  - identifier_name
+  - statement_position
+  - implicit_optional_initialization
+  - force_try
+  - vertical_whitespace
+  - for_where
+  - control_statement
+  - void_function_in_ternary
+  - redundant_discardable_let  # SwiftUI breaks without it
+  # To be enabled as we fix the issues
+  - trailing_whitespace
+  - cyclomatic_complexity
+  - function_body_length
+  - function_parameter_count
+  - type_body_length
+  - file_length
+  - large_tuple
+  - force_cast
+  - multiple_closures_with_trailing_closure
+  - nesting

AI_CONTEXT.md

@@ -1,472 +0,0 @@
-# AI Context for BitChat
-
-This document provides essential context for AI assistants working on the BitChat codebase. Read this first to understand the project's architecture, design decisions, and key concepts.
-
-## Project Overview
-
-BitChat is a decentralized, peer-to-peer messaging application that works over Bluetooth mesh networks without requiring internet connectivity, servers, or phone numbers. It's designed for scenarios where traditional communication infrastructure is unavailable or untrusted.
-
-### Key Features
-- **Bluetooth Mesh Networking**: Multi-hop message relay over BLE
-- **Privacy-First Design**: No accounts, no persistent identifiers
-- **End-to-End Encryption**: Uses Noise Protocol Framework for private messages
-- **Store & Forward**: Messages cached for offline peers
-- **IRC-Style Commands**: Familiar `/msg`, `/who` interface
-- **Cross-Platform**: Native iOS and macOS support
-- **Nostr Integration**: Seamless fallback for mutual favorites when out of Bluetooth range
-- **Hybrid Transport**: Automatic switching between Bluetooth and Nostr
-
-## Architecture Overview
-
-```
-┌─────────────────────────────────────────────────────────────────┐
-│                        User Interface                             │
-│                    (ContentView, ChatViewModel)                   │
-└─────────────────────────────────────────────────────────────────┘
-                                   │
-┌─────────────────────────────────────────────────────────────────┐
-│                     Application Services                          │
-│  (MessageRetryService, DeliveryTracker, NotificationService)     │
-└─────────────────────────────────────────────────────────────────┘
-                                   │
-┌─────────────────────────────────────────────────────────────────┐
-│                      Message Router                               │
-│         (Transport selection, Favorites integration)              │
-└─────────────────────────────────────────────────────────────────┘
-                    │                            │
-┌───────────────────────────────┐ ┌────────────────────────────────┐
-│        Security Layer         │ │      Nostr Protocol Layer      │
-│ (NoiseEncryptionService,      │ │  (NostrProtocol, NIP-17,      │
-│  SecureIdentityStateManager)  │ │   NostrRelayManager)          │
-└───────────────────────────────┘ └────────────────────────────────┘
-                    │                            │
-┌───────────────────────────────┐ ┌────────────────────────────────┐
-│       Protocol Layer          │ │         Transport              │
-│ (BitchatProtocol, Binary-     │ │    (WebSocket to Nostr        │
-│  Protocol, NoiseProtocol)     │ │      relay servers)           │
-└───────────────────────────────┘ └────────────────────────────────┘
-                    │
-┌─────────────────────────────────────────────────────────────────┐
-│                   Bluetooth Transport Layer                       │
-│                   (BluetoothMeshService)                          │
-└─────────────────────────────────────────────────────────────────┘
-```
-
-## Core Components
-
-### 1. BluetoothMeshService (Transport Layer)
-- **Location**: `bitchat/Services/BluetoothMeshService.swift`
-- **Purpose**: Manages BLE connections and implements mesh networking
-- **Key Responsibilities**:
-  - Peer discovery (scanning and advertising simultaneously)
-  - Connection management (acts as both central and peripheral)
-  - Message routing and relay
-  - Version negotiation with peers
-  - Automatic reconnection and topology management
-
-### 2. BitchatProtocol (Protocol Layer)
-- **Location**: `bitchat/Protocols/BitchatProtocol.swift`
-- **Purpose**: Defines the application-level messaging protocol
-- **Key Features**:
-  - Binary packet format for efficiency
-  - Message types: Chat, Announcement, PrivateMessage, etc.
-  - TTL-based routing (max 7 hops)
-  - Message deduplication via unique IDs
-  - Privacy features: padding, timing obfuscation
-
-### 3. NoiseProtocol Implementation
-- **Locations**: 
-  - `bitchat/Noise/NoiseProtocol.swift` - Core protocol implementation
-  - `bitchat/Noise/NoiseSession.swift` - Session management
-  - `bitchat/Services/NoiseEncryptionService.swift` - High-level encryption API
-- **Purpose**: Provides end-to-end encryption for private messages
-- **Implementation Details**:
-  - Uses Noise_XX_25519_AESGCM_SHA256 pattern
-  - Mutual authentication via static keys
-  - Forward secrecy via ephemeral keys
-  - Integrated with identity management
-
-### 4. Identity System
-- **Location**: `bitchat/Identity/`
-- **Three-Layer Model**:
-  1. **Ephemeral Identity**: Short-lived, rotates frequently
-  2. **Cryptographic Identity**: Long-term Noise static keypair
-  3. **Social Identity**: User-chosen nickname and metadata
-- **Trust Levels**: Untrusted → Verified → Trusted → Blocked
-
-### 5. ChatViewModel
-- **Location**: `bitchat/ViewModels/ChatViewModel.swift`
-- **Purpose**: Central state management and business logic
-- **Responsibilities**:
-  - Message handling and batching
-  - Command processing (/msg, /who, etc.)
-  - UI state management
-  - Private chat coordination
-
-### 6. Nostr Integration
-- **Locations**:
-  - `bitchat/Nostr/NostrProtocol.swift` - NIP-17 private message implementation
-  - `bitchat/Nostr/NostrRelayManager.swift` - WebSocket relay connections
-  - `bitchat/Nostr/NostrIdentity.swift` - Nostr key management
-  - `bitchat/Services/MessageRouter.swift` - Transport selection logic
-- **Purpose**: Enables communication with mutual favorites when out of Bluetooth range
-- **Key Features**:
-  - NIP-17 gift-wrapped private messages for metadata privacy
-  - Automatic relay connection management
-  - Seamless transport switching between Bluetooth and Nostr
-  - Integrated with favorites system for mutual authentication
-
-### 7. MessageRouter
-- **Location**: `bitchat/Services/MessageRouter.swift`
-- **Purpose**: Intelligent routing between Bluetooth mesh and Nostr transports
-- **Transport Selection Logic**:
-  1. Always prefer Bluetooth mesh when peer is connected
-  2. Use Nostr for mutual favorites when peer is offline
-  3. Fail gracefully when no transport is available
-- **Message Types Routed**:
-  - Regular chat messages
-  - Favorite/unfavorite notifications
-  - Delivery acknowledgments
-  - Read receipts
-
-## Key Design Decisions
-
-### 1. Protocol Design
-- **Binary Protocol**: Chosen for efficiency over BLE's limited bandwidth
-- **No JSON**: Reduces parsing overhead and message size
-- **Custom Framing**: Handles BLE's 512-byte MTU limitations
-
-### 2. Security Architecture
-- **Noise Protocol**: Industry-standard, well-analyzed framework
-- **XX Pattern**: Provides mutual authentication and forward secrecy
-- **No Long-Term Identifiers**: Enhances privacy and deniability
-
-### 3. Mesh Networking
-- **Store & Forward**: Essential for intermittent connectivity
-- **TTL-Based Routing**: Prevents infinite loops in mesh
-- **Bloom Filters**: Efficient duplicate detection
-
-### 4. Privacy Features
-- **Message Padding**: Obscures message length
-- **Cover Traffic**: Optional dummy messages
-- **Timing Obfuscation**: Randomized delays
-- **Emergency Wipe**: Triple-tap to clear all data
-
-### 5. Nostr Integration
-- **NIP-17 Gift Wraps**: Maximum metadata privacy
-- **Ephemeral Keys**: Each message uses unique ephemeral keys
-- **Mutual Favorites Only**: Requires bidirectional trust
-- **Transport Abstraction**: Users don't need to know about Nostr
-
-## Code Organization
-
-### Services (`/bitchat/Services/`)
-Application-level services that coordinate between layers:
-- `BluetoothMeshService`: Core networking
-- `NoiseEncryptionService`: Encryption coordination
-- `MessageRetryService`: Reliability layer
-- `DeliveryTracker`: Acknowledgment handling
-- `NotificationService`: System notifications
-
-### Protocols (`/bitchat/Protocols/`)
-Protocol definitions and implementations:
-- `BitchatProtocol`: Application protocol
-- `BinaryProtocol`: Low-level encoding
-- `BinaryEncodingUtils`: Helper functions
-
-### Noise (`/bitchat/Noise/`)
-Noise Protocol Framework implementation:
-- `NoiseProtocol`: Core cryptographic operations
-- `NoiseSession`: Session state management
-- `NoiseHandshakeCoordinator`: Handshake orchestration
-- `NoiseSecurityConsiderations`: Security validations
-
-### Views & ViewModels
-MVVM architecture for UI:
-- `ContentView`: Main chat interface
-- `ChatViewModel`: Business logic and state
-- Supporting views for settings, identity, etc.
-
-## Nostr Protocol Implementation
-
-### Overview
-BitChat integrates Nostr as a secondary transport for communicating with mutual favorites when Bluetooth connectivity is unavailable. This integration is transparent to users - messages automatically route through Nostr when needed.
-
-### NIP-17 Private Direct Messages
-BitChat implements NIP-17 (Private Direct Messages) for metadata-private communication:
-
-1. **Gift Wrap Structure**:
-   ```
-   Gift Wrap (kind 1059) → Seal (kind 13) → Rumor (kind 1)
-   ```
-   - **Rumor**: The actual message content (unsigned)
-   - **Seal**: Encrypted rumor, hides sender identity
-   - **Gift Wrap**: Double-encrypted, tagged for recipient
-
-2. **Ephemeral Keys**:
-   - Each message uses TWO ephemeral key pairs
-   - Seal uses one ephemeral key
-   - Gift wrap uses a different ephemeral key
-   - Provides sender anonymity and forward secrecy
-
-3. **Timestamp Randomization**:
-   - ±1 minute randomization (reduced from NIP-17's ±15 minutes)
-   - Prevents timing correlation attacks
-   - Configurable in `NostrProtocol.randomizedTimestamp()`
-
-### Favorites Integration
-
-The Nostr transport is only available for mutual favorites:
-
-1. **Favorite Establishment**:
-   - User favorites a peer via `/fav` command
-   - Favorite notification sent via Bluetooth (if connected)
-   - Peer's Nostr public key exchanged during favorite process
-   - Stored in `FavoritesPersistenceService`
-
-2. **Mutual Requirement**:
-   - Both peers must favorite each other
-   - Prevents spam and unwanted Nostr messages
-   - Enforced by `MessageRouter` transport selection
-
-3. **Nostr Key Management**:
-   - Derived from Noise static key using BIP-32
-   - Path: `m/44'/1237'/0'/0/0` (1237 = "NOSTR" in decimal)
-   - Consistent npub across app reinstalls
-   - Keys never leave the device
-
-### Message Routing Logic
-
-`MessageRouter` automatically selects transport:
-
-```swift
-if peerAvailableOnMesh {
-    transport = .bluetoothMesh  // Always prefer mesh
-} else if isMutualFavorite {
-    transport = .nostr          // Use Nostr for offline favorites
-} else {
-    throw MessageRouterError.peerNotReachable
-}
-```
-
-### Relay Configuration
-
-Default relays (hardcoded for reliability):
-- `wss://relay.damus.io`
-- `wss://relay.primal.net`
-- `wss://offchain.pub`
-- `wss://nostr21.com`
-
-Relay selection criteria:
-- Geographic distribution
-- High uptime
-- No authentication required
-- Support for ephemeral events
-
-### Message Format
-
-Structured content for different message types:
-- Chat: `MSG:<messageID>:<content>`
-- Favorite: `FAVORITED:<senderNpub>` or `UNFAVORITED:<senderNpub>`
-- Delivery ACK: `DELIVERED:<messageID>`
-- Read Receipt: `READ:<base64EncodedReceipt>`
-
-### Implementation Details
-
-1. **NostrRelayManager**:
-   - Manages WebSocket connections to relays
-   - Handles reconnection logic
-   - Processes EVENT, EOSE, OK, NOTICE messages
-   - Implements NIP-01 relay protocol
-
-2. **NostrProtocol**:
-   - Implements NIP-17 encryption/decryption
-   - Handles gift wrap creation/unwrapping
-   - Manages ephemeral key generation
-   - Provides Schnorr signatures
-
-3. **ProcessedMessagesService**:
-   - Prevents duplicate message processing
-   - Tracks last subscription timestamp
-   - Persists across app launches
-   - 30-day retention window
-
-### Security Considerations
-
-1. **Metadata Protection**:
-   - Sender identity hidden via ephemeral keys
-   - Recipient only visible in gift wrap p-tag
-   - Timing correlation prevented via randomization
-   - Message content double-encrypted
-
-2. **Relay Trust**:
-   - Relays cannot read message content
-   - Relays can see recipient pubkey (gift wrap)
-   - Relays cannot determine sender
-   - Multiple relays used for redundancy
-
-3. **Key Hygiene**:
-   - Ephemeral keys used once and discarded
-   - Static Nostr key derived from Noise key
-   - No key reuse between messages
-   - Keys cleared from memory after use
-
-### Debugging Nostr Issues
-
-1. **Check relay connections**:
-   - Look for "Connected to Nostr relay" in logs
-   - Verify WebSocket state in NostrRelayManager
-   - Check for relay errors/notices
-
-2. **Verify gift wrap creation**:
-   - Enable debug logging in NostrProtocol
-   - Check ephemeral key generation
-   - Verify encryption steps
-
-3. **Message delivery**:
-   - Check ProcessedMessagesService for duplicates
-   - Verify subscription filters
-   - Look for EVENT messages in relay responses
-
-## Development Guidelines
-
-### 1. Security First
-- Never log sensitive data (keys, message content)
-- Use `SecureLogger` for security-aware logging
-- Validate all inputs from network
-- Follow principle of least privilege
-
-### 2. Performance Considerations
-- BLE has limited bandwidth (~20KB/s practical)
-- Minimize protocol overhead
-- Batch operations where possible
-- Use compression for large messages
-
-### 3. Testing
-- Unit tests for protocol logic
-- Integration tests for service interactions
-- End-to-end tests for user flows
-- Mock objects for BLE testing
-
-### 4. Error Handling
-- Graceful degradation for network issues
-- Clear error messages for users
-- Automatic retry with backoff
-- Never expose internal errors
-
-## Common Tasks
-
-### Adding a New Message Type
-1. Define in `MessageType` enum in `BitchatProtocol.swift`
-2. Implement encoding/decoding logic
-3. Add handling in `ChatViewModel`
-4. Update UI if needed
-5. Add tests
-
-### Implementing a New Command
-1. Add to `ChatViewModel.processCommand()`
-2. Define any new message types needed
-3. Implement command logic
-4. Add autocomplete support
-5. Update help text
-
-### Debugging Bluetooth Issues
-1. Check `BluetoothMeshService` logs
-2. Verify peer states and connections
-3. Monitor characteristic updates
-4. Use Bluetooth debugging tools
-
-### Working with Nostr Transport
-1. Verify mutual favorite status in `FavoritesPersistenceService`
-2. Check Nostr key derivation in `NostrIdentity`
-3. Monitor relay connections in `NostrRelayManager`
-4. Test gift wrap encryption/decryption
-5. Verify transport selection in `MessageRouter`
-
-### Adding Nostr Features
-1. Understand NIP-17 gift wrap structure
-2. Maintain ephemeral key hygiene
-3. Test with multiple relays
-4. Preserve metadata privacy
-5. Handle relay disconnections gracefully
-
-## Security Threat Model
-
-### Assumptions
-- Adversaries can intercept all Bluetooth traffic
-- Devices may be compromised
-- No trusted infrastructure available
-
-### Protections
-- End-to-end encryption for private messages
-- Message authentication via HMAC
-- Forward secrecy via ephemeral keys
-- Deniability through lack of signatures
-
-### Limitations
-- Public messages are unencrypted by design
-- Metadata (who talks to whom) partially visible
-- Timing attacks possible on mesh network
-- No protection against flooding/spam (yet)
-
-## Performance Optimizations
-
-### Implemented
-- LZ4 compression for messages
-- Adaptive duty cycling for battery
-- Connection caching and reuse
-- Bloom filters for deduplication
-
-### Future Improvements
-- Protocol buffer encoding
-- Better mesh routing algorithms
-- Predictive pre-connection
-- Smarter retransmission
-
-## Troubleshooting Guide
-
-### Common Issues
-1. **Peers not discovering**: Check Bluetooth permissions, ensure app is in foreground
-2. **Messages not delivering**: Verify mesh connectivity, check TTL values
-3. **Handshake failures**: Ensure identity state is consistent, check key storage
-4. **Performance issues**: Monitor connection count, check for message loops
-
-## External Dependencies
-
-### Swift Packages
-- CryptoKit: Apple's crypto framework
-- Network.framework: For future internet support
-- No third-party dependencies (by design)
-
-### System Requirements
-- iOS 14.0+ / macOS 11.0+
-- Bluetooth LE hardware
-- ~50MB storage for app + data
-
-## Future Roadmap
-
-### Planned Features
-- Internet bridging for hybrid networks
-- Group chat with forward secrecy
-- Voice messages with Opus codec
-- File transfer support
-
-### Architecture Evolution
-- Plugin system for transports
-- Modular protocol stack
-- Cross-platform core library
-- Federation between networks
-
----
-
-## Quick Start for AI Assistants
-
-1. **Understand the layers**: Transport → Protocol → Security → Services → UI
-2. **Follow the data flow**: BLE/Nostr → Binary/JSON → Protocol → ViewModel → View
-3. **Respect security boundaries**: Never mix trusted and untrusted data
-4. **Test thoroughly**: This is critical infrastructure for users
-5. **Ask about design decisions**: Many choices have non-obvious reasons
-6. **Dual Transport**: Remember that messages can flow over Bluetooth OR Nostr
-7. **Favorites System**: Nostr only works between mutual favorites
-
-When in doubt, prioritize security and privacy over features. BitChat users depend on this app in situations where traditional communication has failed them.

BRING_THE_NOISE.md

@@ -37,7 +37,7 @@ This three-message pattern provides:
 #### NoiseEncryptionService
 The main service managing all Noise operations:
 ```swift
-class NoiseEncryptionService {
+final class NoiseEncryptionService {
     private let staticIdentityKey: Curve25519.KeyAgreement.PrivateKey
     private let sessionManager: NoiseSessionManager
     private let channelEncryption = NoiseChannelEncryption()
@@ -47,7 +47,7 @@ class NoiseEncryptionService {
 #### NoiseSession
 Individual session state for each peer:
 ```swift
-class NoiseSession {
+final class NoiseSession {
     private var handshakeState: NoiseHandshakeState?
     private var sendCipher: NoiseCipherState?
     private var receiveCipher: NoiseCipherState?
@@ -58,7 +58,7 @@ class NoiseSession {
 #### NoiseSessionManager
 Thread-safe session management:
 ```swift
-class NoiseSessionManager {
+final class NoiseSessionManager {
     private var sessions: [String: NoiseSession] = [:]
     private let sessionsQueue = DispatchQueue(label: "noise.sessions", attributes: .concurrent)
 }

Configs/Debug.xcconfig

@@ -0,0 +1,4 @@
+#include "Release.xcconfig"
+
+// Optional include of local configs
+#include? "Local.xcconfig"

Configs/Local.xcconfig.example

@@ -0,0 +1,5 @@
+// Your Apple Developer Team ID - https://stackoverflow.com/a/18727947
+DEVELOPMENT_TEAM = ABC123
+
+// Unique bundle id to be able to register and run locally
+PRODUCT_BUNDLE_IDENTIFIER = chat.bitchat.$(DEVELOPMENT_TEAM)

Configs/Release.xcconfig

@@ -0,0 +1,12 @@
+MARKETING_VERSION = 1.5.4
+CURRENT_PROJECT_VERSION = 1
+
+IPHONEOS_DEPLOYMENT_TARGET = 16.0
+MACOSX_DEPLOYMENT_TARGET = 13.0
+SWIFT_VERSION = 5.0
+
+DEVELOPMENT_TEAM = L3N5LHJD5Y
+CODE_SIGN_STYLE = Automatic
+
+PRODUCT_BUNDLE_IDENTIFIER = chat.bitchat
+APP_GROUP_ID = group.chat.bitchat

Justfile

@@ -14,16 +14,16 @@ default:
 # Check prerequisites
 check:
     @echo "Checking prerequisites..."
-    @command -v xcodegen >/dev/null 2>&1 || (echo "❌ XcodeGen not found. Install with: brew install xcodegen" && exit 1)
-    @command -v xcodebuild >/dev/null 2>&1 || (echo "❌ Xcode not found. Install Xcode from App Store" && exit 1)
-    @security find-identity -v -p codesigning | grep -q "Developer ID" || (echo "⚠️  No Developer ID found - code signing may fail" && exit 0)
+    @command -v xcodebuild >/dev/null 2>&1 || (echo "❌ xcodebuild not found. Install Xcode from App Store" && exit 1)
+    @xcode-select -p | grep -q "Xcode.app" || (echo "❌ Full Xcode required, not just command line tools. Install from App Store and run:\n   sudo xcode-select -s /Applications/Xcode.app/Contents/Developer" && exit 1)
+    @test -d "/Applications/Xcode.app" || (echo "❌ Xcode.app not found in Applications folder. Install from App Store" && exit 1)
+    @xcodebuild -version >/dev/null 2>&1 || (echo "❌ Xcode not properly configured. Try:\n   sudo xcode-select -s /Applications/Xcode.app/Contents/Developer" && exit 1)
+    @security find-identity -v -p codesigning | grep -q "Apple Development\|Developer ID" || (echo "⚠️  No Developer ID found - code signing may fail" && exit 0)
     @echo "✅ All prerequisites met"
 
 # Backup original files
 backup:
     @echo "Backing up original project configuration..."
-    @cp project.yml project.yml.backup 2>/dev/null || true
-    @# Backup other files that get modified by xcodegen
     @if [ -f bitchat.xcodeproj/project.pbxproj ]; then cp bitchat.xcodeproj/project.pbxproj bitchat.xcodeproj/project.pbxproj.backup; fi
     @if [ -f bitchat/Info.plist ]; then cp bitchat/Info.plist bitchat/Info.plist.backup; fi
 
@@ -44,20 +44,15 @@ patch-for-macos: backup
     @# Move iOS-specific files out of the way temporarily
     @if [ -f bitchat/LaunchScreen.storyboard ]; then mv bitchat/LaunchScreen.storyboard bitchat/LaunchScreen.storyboard.ios; fi
 
-# Generate Xcode project with patches
-generate: patch-for-macos
-    @echo "Generating Xcode project..."
-    @xcodegen generate
-
 # Build the macOS app
-build: check generate
+build: #check generate
     @echo "Building BitChat for macOS..."
     @xcodebuild -project bitchat.xcodeproj -scheme "bitchat (macOS)" -configuration Debug CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO CODE_SIGN_ENTITLEMENTS="" build
 
 # Run the macOS app
 run: build
     @echo "Launching BitChat..."
-    @find ~/Library/Developer/Xcode/DerivedData -name "bitchat.app" -path "*/Debug/*" | head -1 | xargs -I {} open "{}"
+    @find ~/Library/Developer/Xcode/DerivedData -name "bitchat.app" -path "*/Debug/*" -not -path "*/Index.noindex/*" | head -1 | xargs -I {} open "{}"
 
 # Clean build artifacts and restore original files
 clean: restore
@@ -75,10 +70,8 @@ clean: restore
 # Quick run without cleaning (for development)
 dev-run: check
     @echo "Quick development build..."
-    @if [ ! -f project.yml.backup ]; then just patch-for-macos; fi
-    @xcodegen generate
-    @xcodebuild -project bitchat.xcodeproj -scheme "bitchat (macOS)" -configuration Debug CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO CODE_SIGN_ENTITLEMENTS="" build
-    @find ~/Library/Developer/Xcode/DerivedData -name "bitchat.app" -path "*/Debug/*" | head -1 | xargs -I {} open "{}"
+    @xcodebuild -project bitchat.xcodeproj -scheme "bitchat_macOS" -configuration Debug CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO CODE_SIGN_ENTITLEMENTS="" build
+    @find ~/Library/Developer/Xcode/DerivedData -name "bitchat.app" -path "*/Debug/*" -not -path "*/Index.noindex/*" | head -1 | xargs -I {} open "{}"
 
 # Show app info
 info:
@@ -106,11 +99,9 @@ nuke:
     @echo "🧨 Nuclear clean - removing all build artifacts and backups..."
     @rm -rf ~/Library/Developer/Xcode/DerivedData/bitchat-* 2>/dev/null || true
     @rm -rf bitchat.xcodeproj 2>/dev/null || true
-    @rm -f project.yml.backup 2>/dev/null || true
-    @rm -f project-macos.yml 2>/dev/null || true
     @rm -f bitchat.xcodeproj/project.pbxproj.backup 2>/dev/null || true
     @rm -f bitchat/Info.plist.backup 2>/dev/null || true
     @# Restore iOS-specific files if they were moved
     @if [ -f bitchat/LaunchScreen.storyboard.ios ]; then mv bitchat/LaunchScreen.storyboard.ios bitchat/LaunchScreen.storyboard; fi
-    @git checkout -- project.yml bitchat.xcodeproj/project.pbxproj bitchat/Info.plist 2>/dev/null || echo "⚠️  Not a git repo or no changes to restore"
+    @git checkout bitchat.xcodeproj/project.pbxproj bitchat/Info.plist 2>/dev/null || echo "⚠️  Not a git repo or no changes to restore"
     @echo "✅ Nuclear clean complete"

PRIVACY_POLICY.md

@@ -1,6 +1,6 @@
 # bitchat Privacy Policy
 
-*Last updated: January 2025*
+*Last updated: June 2026*
 
 ## Our Commitment
 
@@ -9,7 +9,7 @@ bitchat is designed with privacy as its foundation. We believe private communica
 ## Summary
 
 - **No personal data collection** - We don't collect names, emails, or phone numbers
-- **No servers** - Everything happens on your device and through peer-to-peer connections
+- **No accounts or company servers** - Mesh chat works peer-to-peer; optional Nostr features use public or user-selected relays
 - **No tracking** - We have no analytics, telemetry, or user tracking
 - **Open source** - You can verify these claims by reading our code
 
@@ -17,11 +17,11 @@ bitchat is designed with privacy as its foundation. We believe private communica
 
 ### On Your Device Only
 
-1. **Identity Key** 
-   - A cryptographic key generated on first launch
+1. **Identity Keys**
+   - Cryptographic private keys generated on first launch or when optional Nostr identities are created
    - Stored locally in your device's secure storage
    - Allows you to maintain "favorite" relationships across app restarts
-   - Never leaves your device
+   - Private keys never leave your device; public keys are shared when needed for messaging
 
 2. **Nickname**
    - The display name you choose (or auto-generated)
@@ -38,12 +38,19 @@ bitchat is designed with privacy as its foundation. We believe private communica
    - Stored only on your device
    - Allows you to recognize these peers in future sessions
 
+5. **Optional Location Channel State**
+   - Your selected geohash channel, bookmarked geohashes, teleport flags, and bookmark display names
+   - Stored locally on your device so the location-channel UI can restore your choices
+   - Per-geohash Nostr identities are derived locally from a device seed stored in secure storage
+   - Exact latitude and longitude are not persisted by bitchat
+
 ### Temporary Session Data
 
 During each session, bitchat temporarily maintains:
 - Active peer connections (forgotten when app closes)
 - Routing information for message delivery
 - Cached messages for offline peers (12 hours max)
+- Your current location while optional location channels are enabled, used locally to compute geohash channels and friendly place names
 
 ## What Information is Shared
 
@@ -62,13 +69,21 @@ When you join a password-protected room:
 - Your nickname appears in the member list
 - Room owners can see you've joined
 
+### With Nostr Relays (Optional Features)
+
+If you enable Nostr-backed features:
+- Private fallback messages to mutual favorites are sent as encrypted NIP-17 gift wraps. Relays can see event metadata, but not message content.
+- Public location-channel messages, location notes, and presence are scoped with geohash tags. Relays and other participants can see the geohash tag, event kind, timestamp, and public key used for that geohash.
+- Exact GPS coordinates are not included in Nostr events by bitchat. The geohash precision you choose can still reveal an approximate area, from region-level to building-level.
+- Automatic presence heartbeats are limited to low-precision geohashes (region, province, and city). More precise geohash posts happen only when you use those channels or location notes.
+
 ## What We DON'T Do
 
 bitchat **never**:
 - Collects personal information
-- Tracks your location
-- Stores data on servers
-- Shares data with third parties
+- Sells or shares your exact GPS location
+- Stores data on servers we operate
+- Sells your data to advertisers or data brokers
 - Uses analytics or telemetry
 - Creates user profiles
 - Requires registration
@@ -84,19 +99,27 @@ All private messages use end-to-end encryption:
 ## Your Rights
 
 You have complete control:
-- **Delete Everything**: Triple-tap the logo to instantly wipe all data
-- **Leave Anytime**: Close the app and your presence disappears
-- **No Account**: Nothing to delete from servers because there are none
-- **Portability**: Your data never leaves your device unless you export it
+- **Delete Local State**: Triple-tap the logo to instantly wipe local keys, sessions, caches, and preferences
+- **Leave Anytime**: Close the app and local presence stops; relay-backed presence ages out
+- **No Account**: No account record exists for you to delete from us
+- **Portability**: Your local state stays on your device unless you send messages, use optional relay-backed features, or export it
 
 ## Bluetooth & Permissions
 
 bitchat requires Bluetooth permission to function:
 - Used only for peer-to-peer communication
-- No location data is accessed or stored
 - Bluetooth is not used for tracking
 - You can revoke this permission at any time in system settings
 
+## Location Permission
+
+Location permission is optional and is used only for location channels:
+- Used to compute local geohash channels and display names
+- Requested as when-in-use permission
+- Exact coordinates are not shared in messages or stored by bitchat
+- Selected and bookmarked geohashes may persist locally until you remove them, use panic wipe, or delete the app
+- You can revoke this permission at any time in system settings
+
 ## Children's Privacy
 
 bitchat does not knowingly collect information from children. The app has no age verification because it collects no personal information from anyone.
@@ -106,12 +129,15 @@ bitchat does not knowingly collect information from children. The app has no age
 - **Messages**: Deleted from memory when app closes (unless room retention is enabled)
 - **Identity Key**: Persists until you delete the app
 - **Favorites**: Persist until you remove them or delete the app
+- **Location channel choices**: Selected/bookmarked geohashes persist locally until removed, panic-wiped, or the app is deleted
+- **Nostr relay data**: Public geohash events and encrypted gift wraps may be retained by relays according to each relay's policy
 - **Everything Else**: Exists only during active sessions
 
 ## Security Measures
 
 - All communication is encrypted
-- No data transmitted to servers (there are none)
+- No accounts or company servers
+- Optional Nostr relays receive only the events needed for Nostr-backed private fallback or public location channels
 - Open source code for public audit
 - Regular security updates
 - Cryptographic signatures prevent tampering
@@ -121,7 +147,7 @@ bitchat does not knowingly collect information from children. The app has no age
 If we update this policy:
 - The "Last updated" date will change
 - The updated policy will be included in the app
-- No retroactive changes can affect data (since we don't collect any)
+- No retroactive changes can make us collect data already held only in your app
 
 ## Contact
 
@@ -132,7 +158,7 @@ bitchat is an open source project. For privacy questions:
 
 ## Philosophy
 
-Privacy isn't just a feature—it's the entire point. bitchat proves that modern communication doesn't require surrendering your privacy. No accounts, no servers, no surveillance. Just people talking freely.
+Privacy isn't just a feature—it's the entire point. bitchat proves that modern communication doesn't require surrendering your privacy. No accounts, no company servers, no analytics. Just people talking freely.
 
 ---
 

Package.resolved

@@ -0,0 +1,14 @@
+{
+  "pins" : [
+    {
+      "identity" : "swift-secp256k1",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/21-DOT-DEV/swift-secp256k1",
+      "state" : {
+        "revision" : "8c62aba8a3011c9bcea232e5ee007fb0b34a15e2",
+        "version" : "0.21.1"
+      }
+    }
+  ],
+  "version" : 2
+}

Package.swift

@@ -4,6 +4,7 @@ import PackageDescription
 
 let package = Package(
     name: "bitchat",
+    defaultLocalization: "en",
     platforms: [
         .iOS(.v16),
         .macOS(.v13)
@@ -12,19 +13,58 @@ let package = Package(
         .executable(
             name: "bitchat",
             targets: ["bitchat"]
-        ),
+        )
+    ],
+    dependencies: [
+        .package(path: "localPackages/Arti"),
+        .package(path: "localPackages/BitFoundation"),
+        .package(path: "localPackages/BitLogger"),
+        .package(url: "https://github.com/21-DOT-DEV/swift-secp256k1", exact: "0.21.1")
     ],
     targets: [
         .executableTarget(
             name: "bitchat",
+            dependencies: [
+                .product(name: "P256K", package: "swift-secp256k1"),
+                .product(name: "BitFoundation", package: "BitFoundation"),
+                .product(name: "BitLogger", package: "BitLogger"),
+                .product(name: "Tor", package: "Arti")
+            ],
             path: "bitchat",
             exclude: [
                 "Info.plist",
                 "Assets.xcassets",
+                "_PreviewHelpers/PreviewAssets.xcassets",
                 "bitchat.entitlements",
                 "bitchat-macOS.entitlements",
-                "LaunchScreen.storyboard"
+                "LaunchScreen.storyboard",
+                "ViewModels/Extensions/README.md"
+            ],
+            resources: [
+                .process("Localizable.xcstrings")
             ]
         ),
+        .testTarget(
+            name: "bitchatTests",
+            dependencies: [
+                "bitchat",
+                .product(name: "BitFoundation", package: "BitFoundation")
+            ],
+            path: "bitchatTests",
+            exclude: [
+                "Info.plist",
+                "README.md",
+                // CI perf gate data (read by scripts/check-perf-floors.sh),
+                // not a test resource.
+                "Performance/perf-floors.json"
+            ],
+            resources: [
+                .process("Localization"),
+                // Only the vector fixture: declaring the whole "Noise"
+                // directory would claim its .swift test files as resources
+                // and silently drop them from compilation.
+                .process("Noise/NoiseTestVectors.json")
+            ]
+        )
     ]
-)
+)

README.md

@@ -1,90 +1,122 @@
-<img height="300" alt="bitchat" src="https://github.com/user-attachments/assets/2660f828-49c7-444d-beca-d8b01854667a" />
+<img width="256" height="256" alt="icon_128x128@2x" src="https://github.com/user-attachments/assets/90133f83-b4f6-41c6-aab9-25d0859d2a47" />
 
 ## bitchat
 
-A decentralized peer-to-peer messaging app that works over Bluetooth mesh networks. No internet required, no servers, no phone numbers. It's the side-groupchat. 
+A decentralized peer-to-peer messaging app with dual transport architecture: local Bluetooth mesh networks for offline communication and internet-based Nostr protocol for global reach. No accounts, no phone numbers, no central servers. It's the side-groupchat.
 
 [bitchat.free](http://bitchat.free)
+
 📲 [App Store](https://apps.apple.com/us/app/bitchat-mesh/id6748219622)
 
-> [!WARNING]
-> Private message and channel features have not received external security review and may contain vulnerabilities. Do not use for sensitive use cases, and do not rely on its security until it has been reviewed. Now uses the [Noise Protocol](http://www.noiseprotocol.org) for identity and encryption. Public local chat (the main feature) has no security concerns. 
-
-
 ## License
 
 This project is released into the public domain. See the [LICENSE](LICENSE) file for details.
 
-
 ## Features
 
+- **Dual Transport Architecture**: Bluetooth mesh for offline + Nostr protocol for internet-based messaging
+- **Location-Based Channels**: Geographic chat rooms using geohash coordinates over global Nostr relays
+- **Intelligent Message Routing**: Automatically chooses best transport (Bluetooth → Nostr fallback)
 - **Decentralized Mesh Network**: Automatic peer discovery and multi-hop message relay over Bluetooth LE
 - **Privacy First**: No accounts, no phone numbers, no persistent identifiers
-- **Cover Traffic**: Timing obfuscation and dummy messages for enhanced privacy
-- **Private Message End-to-End Encryption**: [Noise Protocol](http://noiseprotocol.org)
-- **Store & Forward**: Messages cached for offline peers and delivered when they reconnect
+- **Private Message End-to-End Encryption**: [Noise Protocol](https://noiseprotocol.org) for mesh, NIP-17 for Nostr
 - **IRC-Style Commands**: Familiar `/slap`, `/msg`, `/who` style interface
 - **Universal App**: Native support for iOS and macOS
 - **Emergency Wipe**: Triple-tap to instantly clear all data
 - **Performance Optimizations**: LZ4 message compression, adaptive battery modes, and optimized networking
 
+## [Technical Architecture](https://deepwiki.com/permissionlesstech/bitchat)
 
-## Technical Architecture
+BitChat uses a **hybrid messaging architecture** with two complementary transport layers:
 
-### Binary Protocol
-bitchat uses an efficient binary protocol optimized for Bluetooth LE:
-- Compact packet format with 1-byte type field
-- TTL-based message routing (max 7 hops)
-- Automatic fragmentation for large messages
-- Message deduplication via unique IDs
+### Bluetooth Mesh Network (Offline)
 
-### Mesh Networking
-- Each device acts as both client and peripheral
-- Automatic peer discovery and connection management
-- Store-and-forward for offline message delivery
-- Adaptive duty cycling for battery optimization
+- **Local Communication**: Direct peer-to-peer within Bluetooth range
+- **Multi-hop Relay**: Messages route through nearby devices (max 7 hops)
+- **No Internet Required**: Works completely offline in disaster scenarios
+- **Noise Protocol Encryption**: End-to-end encryption with forward secrecy
+- **Binary Protocol**: Compact packet format optimized for Bluetooth LE constraints
+- **Automatic Discovery**: Peer discovery and connection management
+- **Adaptive Power**: Battery-optimized duty cycling
+
+### Nostr Protocol (Internet)
+
+- **Global Reach**: Connect with users worldwide via internet relays
+- **Location Channels**: Geographic chat rooms using geohash coordinates
+- **290+ Relay Network**: Distributed across the globe for reliability
+- **NIP-17 Encryption**: Gift-wrapped private messages for internet privacy
+- **Ephemeral Keys**: Fresh cryptographic identity per geohash area
+
+### Channel Types
+
+#### `mesh #bluetooth`
+
+- **Transport**: Bluetooth Low Energy mesh network
+- **Scope**: Local devices within multi-hop range
+- **Internet**: Not required
+- **Use Case**: Offline communication, protests, disasters, remote areas
+
+#### Location Channels (`block #dr5rsj7`, `neighborhood #dr5rs`, `country #dr`)
+
+- **Transport**: Nostr protocol over internet
+- **Scope**: Geographic areas defined by geohash precision
+  - `block` (7 chars): City block level
+  - `neighborhood` (6 chars): District/neighborhood
+  - `city` (5 chars): City level
+  - `province` (4 chars): State/province
+  - `region` (2 chars): Country/large region
+- **Internet**: Required (connects to Nostr relays)
+- **Use Case**: Location-based community chat, local events, regional discussions
+
+### Direct Message Routing
+
+Private messages use **intelligent transport selection**:
+
+1. **Bluetooth First** (preferred when available)
+
+   - Direct connection with established Noise session
+   - Fastest and most private option
+
+2. **Nostr Fallback** (when Bluetooth unavailable)
+
+   - Uses recipient's Nostr public key
+   - NIP-17 gift-wrapping for privacy
+   - Routes through global relay network
+
+3. **Smart Queuing** (when neither available)
+   - Messages queued until transport becomes available
+   - Automatic delivery when connection established
 
 For detailed protocol documentation, see the [Technical Whitepaper](WHITEPAPER.md).
 
-
 ## Setup
 
-### Option 1: Using XcodeGen (Recommended)
+### Option 1: Using Xcode
 
-1. Install XcodeGen if you haven't already:
-   ```bash
-   brew install xcodegen
-   ```
-
-2. Generate the Xcode project:
    ```bash
    cd bitchat
-   xcodegen generate
-   ```
-
-3. Open the generated project:
-   ```bash
    open bitchat.xcodeproj
    ```
 
-### Option 2: Using Swift Package Manager
+   To run on a device there're a few steps to prepare the code:
+   - Clone the local configs: `cp Configs/Local.xcconfig.example Configs/Local.xcconfig`
+   - Add your Developer Team ID into the newly created `Configs/Local.xcconfig`
+      - Bundle ID would be set to `chat.bitchat.<team_id>` (unless you set to something else)
+   - Entitlements need to be updated manually (TODO: Automate):
+      - Search and replace `group.chat.bitchat` with `group.<your_bundle_id>` (e.g. `group.chat.bitchat.ABC123`)
+
+### Option 2: Using `just`
 
-1. Open the project in Xcode:
    ```bash
-   cd bitchat
-   open Package.swift
+   brew install just
    ```
 
-2. Select your target device and run
-
-### Option 3: Manual Xcode Project
-
-1. Open Xcode and create a new iOS/macOS App
-2. Copy all Swift files from the `bitchat` directory into your project
-3. Update Info.plist with Bluetooth permissions
-4. Set deployment target to iOS 16.0 / macOS 13.0
-
-### Option 4: just
-
-Want to try this on macos: `just run` will set it up and run from source. 
+Want to try this on macos: `just run` will set it up and run from source.
 Run `just clean` afterwards to restore things to original state for mobile app building and development.
+
+## Localization
+
+- Base app resources live under `bitchat/Localization/Base.lproj/`. Add new copy to `Localizable.strings` and plural rules to `Localizable.stringsdict`.
+- Share extension strings are separate in `bitchatShareExtension/Localization/Base.lproj/Localizable.strings`.
+- Prefer keys that describe intent (`app_info.features.offline.title`) and reuse existing ones where possible.
+- Run `xcodebuild -project bitchat.xcodeproj -scheme "bitchat (macOS)" -configuration Debug CODE_SIGNING_ALLOWED=NO build` to compile-check any localization updates.

WHITEPAPER.md

@@ -1,268 +1,141 @@
-# BitChat Protocol Whitepaper
+# bitchat Protocol Whitepaper
 
-**Version 1.1**
+**Version 2.0**
 
-**Date: July 25, 2025**
+**Date: July 6, 2026**
 
 ---
 
 ## Abstract
 
-BitChat is a decentralized, peer-to-peer messaging application designed for secure, private, and censorship-resistant communication over ephemeral, ad-hoc networks. This whitepaper details the BitChat Protocol Stack, a layered architecture that combines a modern cryptographic foundation with a flexible application protocol. At its core, BitChat leverages the Noise Protocol Framework (specifically, the `XX` pattern) to establish mutually authenticated, end-to-end encrypted sessions between peers. This document provides a technical specification of the identity management, session lifecycle, message framing, and security considerations that underpin the BitChat network.
+bitchat is a decentralized, peer-to-peer messaging application for secure, private, censorship-resistant communication that works with or without the internet. Nearby devices form an ad-hoc Bluetooth Low Energy (BLE) mesh; distant peers are reached over the Nostr protocol when a connection exists. A layered store-and-forward stack — a persistent sender outbox, opportunistic couriers with a spray-and-wait copy budget, gossip-synced public history, and Nostr relay mailboxes — delivers messages to peers who are out of range at send time. This document describes the protocol and its delivery guarantees as implemented.
 
 ---
 
-## 1. Introduction
+## 1. Design Goals
 
-In an era of centralized communication platforms, BitChat offers a resilient alternative by operating without central servers. It is designed for scenarios where internet connectivity is unavailable or untrustworthy, such as protests, natural disasters, or remote areas. Communication occurs directly between devices over transports like Bluetooth Low Energy (BLE).
+* **Confidentiality:** all private communication is end-to-end encrypted; intermediate nodes and couriers carry only opaque ciphertext.
+* **Authentication:** peers are identified by cryptographic keys; announcements are signed and verified.
+* **Resilience:** the network functions in lossy, low-bandwidth, partitioned environments with churning membership.
+* **Eventual delivery:** a message to an out-of-range peer should still arrive — relayed by the mesh, carried by a moving person, or resting on an internet relay — within a bounded retention window.
+* **Ephemerality by default:** no plaintext message content is ever written to disk. Everything the store-and-forward stack persists is either sealed ciphertext or already-public broadcast traffic, and all of it dies with the panic wipe.
 
-The design goals of the BitChat Protocol are:
+## 2. Architecture Overview
 
-*   **Confidentiality:** All communication must be unreadable to third parties.
-*   **Authentication:** Users must be able to verify the identity of their correspondents.
-*   **Integrity:** Messages cannot be tampered with in transit.
-*   **Forward Secrecy:** The compromise of long-term identity keys must not compromise past session keys.
-*   **Deniability:** It should be difficult to cryptographically prove that a specific user sent a particular message.
-*   **Resilience:** The protocol must function reliably in lossy, low-bandwidth environments.
+Two transports implement a common `Transport` interface and are coordinated by a `MessageRouter`:
 
-This paper specifies the technical details of the protocol designed to meet these goals.
+* **BLE mesh** — every device is simultaneously a GATT central and peripheral, relaying packets in a controlled flood. No infrastructure, pairing, or accounts.
+* **Nostr** — private messages to mutual favorites travel as NIP-17 gift-wrapped events over public relays (over Tor where enabled), bridging separate meshes through the internet.
 
----
+The router prefers a live mesh link, falls back to Nostr, and engages the courier system when neither can deliver promptly.
 
-## 2. Protocol Stack
+## 3. Identity
 
-The BitChat Protocol is a four-layer stack. This layered approach separates concerns, allowing for modularity and future extensibility.
+Each device holds two long-term key pairs in the Keychain:
 
-```mermaid
-graph TD
-    A[Application Layer] --> B[Session Layer];
-    B --> C[Encryption Layer];
-    C --> D[Transport Layer];
+* a **Curve25519 static key** for Noise key agreement — its SHA-256 fingerprint is the peer's stable identity, and
+* an **Ed25519 signing key** for packet signatures.
 
-    subgraph "BitChat Application"
-        A
-    end
+On the mesh, peers appear under short ephemeral IDs derived per session; favoriting pins the full Noise public key so identity survives across sessions. Mutual favorites also exchange Nostr public keys for the internet path. Optional QR verification binds a nickname to a fingerprint in person.
 
-    subgraph "Message Framing & State"
-        B
-    end
+## 4. BLE Mesh Layer
 
-    subgraph "Noise Protocol Framework"
-        C
-    end
+### 4.1 Packet Format
 
-    subgraph "BLE, Wi-Fi Direct, etc."
-        D
-    end
+A compact binary header (version, type, TTL, timestamp, flags) is followed by an 8-byte sender ID, an optional 8-byte recipient ID, the payload, and an optional Ed25519 signature. Version 2 packets may carry an explicit source route. Signatures exclude the TTL byte so relays can decrement it without invalidating them. Packets other than fragments are padded toward uniform sizes.
 
-    style A fill:#cde4ff
-    style B fill:#b5d8ff
-    style C fill:#9ac2ff
-    style D fill:#7eadff
-```
+### 4.2 Flood Control
 
-*   **Application Layer:** Defines the structure of user-facing messages (`BitchatMessage`), acknowledgments (`DeliveryAck`), and other application-level data.
-*   **Session Layer:** Manages the overall communication packet (`BitchatPacket`). This includes routing information (TTL), message typing, fragmentation, and serialization into a compact binary format.
-*   **Encryption Layer:** Establishes and manages secure channels using the Noise Protocol Framework. It is responsible for the cryptographic handshake, session management, and transport message encryption/decryption.
-*   **Transport Layer:** The underlying physical medium used for data transmission, such as Bluetooth Low Energy (BLE). This layer is abstracted away from the core protocol.
+Relaying is a deterministic controlled flood tuned by local connection degree:
 
----
+* **TTL:** packets originate with TTL 7. Relays clamp: dense graphs (≥ 6 links) cap broadcast TTL at 5; thin chains (≤ 2 links) relay at full incoming depth.
+* **Deduplication:** an LRU seen-set (1000 entries, 5-minute expiry) keyed by sender, timestamp, type, and a payload digest drops duplicates. A scheduled relay is cancelled when a duplicate arrives first from another relay.
+* **Jitter:** relays wait a random 10–220 ms (wider when dense) so duplicate suppression wins often.
+* **Fanout subsetting:** broadcast messages are re-sent to a deterministic, message-ID-seeded subset of links (~log₂ of degree) rather than all of them; announces, fragments, and sync packets use full fanout. The ingress link is always excluded (split horizon).
+* **Directed traffic** (handshakes, private messages, courier envelopes) relays deterministically with TTL − 1 and tight jitter, and is never subset.
 
-## 3. Identity and Key Management
+### 4.3 Routing
 
-A peer's identity in BitChat is defined by two persistent cryptographic key pairs, which are generated on first launch and stored securely in the device's Keychain.
+Announcements carry up to 10 direct-neighbor IDs, giving each node a shallow topology map (60 s freshness). When a bidirectionally-confirmed path exists, packets are source-routed along it; otherwise — and whenever a route fails — delivery falls back to flooding.
 
-1.  **Noise Static Key Pair (`Curve25519`):** This is the long-term identity key used for the Noise Protocol handshake. The public part of this key is shared with peers to establish secure sessions.
-2.  **Signing Key Pair (`Ed25519`):** This key is used to sign announcements and other protocol messages where non-repudiation is required, such as binding a public key to a nickname.
+### 4.4 Fragmentation
 
-### 3.1. Fingerprint
+Packets exceeding the link MTU split into ~469-byte fragments (8-byte fragment ID, index/total header) that relay independently and reassemble at each receiving node (128 concurrent assemblies, 30 s timeout, 1 MiB cap).
 
-A user's unique, verifiable fingerprint is the **SHA-256 hash** of their **Noise static public key**. This provides a user-friendly and secure way to verify an identity out-of-band (e.g., by reading it aloud or scanning a QR code).
+### 4.5 Presence
 
-`Fingerprint = SHA256(StaticPublicKey_Curve25519)`
+Signed announcements propagate multi-hop: every 4 s while isolated, backing off to ~15–30 s (jittered) when connected. A verified announce retains a peer as *reachable* for 60 s after last contact. Connection scheduling is RSSI-gated with duty-cycled scanning to bound battery drain.
 
-### 3.2. Identity Management
+## 5. Encryption
 
-The `SecureIdentityStateManager` class is responsible for managing all cryptographic identity material and social metadata (petnames, trust levels, etc.). It uses an in-memory cache for performance and persists this cache to the Keychain after encrypting it with a separate AES-GCM key.
+### 5.1 Live Sessions: Noise XX
 
----
+Connected peers establish sessions with the Noise `XX` pattern (Curve25519 / ChaCha20-Poly1305 / SHA-256), providing mutual authentication and forward secrecy. All private payloads — messages, delivery acks, read receipts — ride inside the session as typed ciphertext. Intermediate relays see only opaque `noiseEncrypted` packets.
 
-## 4. The Social Trust Layer
+### 5.2 Offline Seals: Noise X
 
-Beyond cryptographic identity, BitChat incorporates a social trust layer, allowing users to manage their relationships with peers. This functionality is handled by the `SecureIdentityStateManager`.
+Courier envelopes are sealed to the recipient's *static* key with the one-way Noise `X` pattern; the sender's identity is authenticated inside the ciphertext. **This path has no forward secrecy** — compromise of the recipient's static key exposes sealed-but-undelivered mail. A prekey scheme is future work.
 
-### 4.1. Peer Verification
+### 5.3 Nostr Path
 
-While the Noise handshake cryptographically authenticates a peer's key, it doesn't confirm the real-world identity of the person holding the device. To solve this, users can perform out-of-band (OOB) verification by comparing fingerprints. Once a user confirms that a peer's fingerprint matches the one they expect, they can mark that peer as "verified". This status is stored locally and displayed in the UI, providing a strong assurance of identity for future conversations.
+Private messages to mutual favorites are wrapped per NIP-17/NIP-59: a rumor (kind 14) sealed (kind 13) and gift-wrapped (kind 1059) under a throwaway ephemeral key, so relays learn neither sender nor content.
 
-### 4.2. Favorites and Blocking
+## 6. Store and Forward
 
-To improve the user experience and provide control over interactions, the protocol supports:
-*   **Favorites:** Users can mark trusted or frequently contacted peers as "favorites." This is a local designation that can be used by the application to prioritize notifications or display peers more prominently.
-*   **Blocking:** Users can block peers. When a peer is blocked, the application will discard any incoming packets from that peer's fingerprint at the earliest possible stage, effectively silencing them without notifying the blocked peer.
+Four mechanisms cover the "recipient is not here right now" problem. All persisted state is wiped by panic mode.
 
----
+### 6.1 Sender Outbox
 
-## 5. The Noise Protocol Layer
+Private messages without a prompt route are retained per peer (100 messages/peer, 24 h TTL) and re-sent on reconnect events until a delivery or read ack clears them, or a resend cap (8 attempts) drops them with visible failure. The outbox persists to disk sealed under a ChaChaPoly key held only in the Keychain, so queued mail survives an app kill without ever storing plaintext.
 
-BitChat implements the Noise Protocol Framework to provide strong, authenticated end-to-end encryption.
+### 6.2 Couriers
 
-### 5.1. Protocol Name
+When no transport can deliver promptly, the message is sealed (§5.2) into a **courier envelope** and handed to up to 3 connected peers who may physically encounter the recipient:
 
-The specific Noise protocol implemented is:
+* **Opaque addressing.** The only routing information is a 16-byte rotating recipient tag — an HMAC of the recipient's static key and the UTC day — computable solely by parties who already know that key. Couriers learn neither sender, recipient, nor content, and tags do not correlate across days.
+* **Trust tiers.** Mutual favorites may deposit 5 envelopes each; any peer with a signature-verified announce may deposit 2, into a bounded pool (20 of 40 slots) that can never crowd out favorites' mail. Envelopes are capped at 16 KiB and 24 h; overflow evicts oldest verified-tier mail first.
+* **Deposit retry.** Queued messages are re-deposited whenever a new eligible courier connects, until 3 distinct couriers carry the message or it expires.
+* **Spray and wait.** Envelopes carry a copy budget (initially 4, capped at 8). A courier meeting another eligible courier hands over half its remaining budget, so mail diffuses through a moving crowd instead of riding one person. Budgets, spray history, and carried mail persist across app restarts (iOS file protection).
+* **Handover.** On a verified *direct* announce from the recipient, matching envelopes are delivered over the live link and removed. On a verified *relayed* announce, a copy floods toward the recipient as a directed packet while the carried original stays put, throttled to one attempt per envelope per 10 minutes.
+* Receivers dedup by message ID, so redundant copies and the retained outbox original are harmless. Couriered mail from blocked senders is dropped at decryption time.
 
-**`Noise_XX_25519_ChaChaPoly_SHA256`**
+### 6.3 Public History (Gossip Sync)
 
-*   **`XX` Pattern:** This handshake pattern provides mutual authentication and forward secrecy. It does not require either party to know the other's static public key before the handshake begins. The keys are exchanged and authenticated during the three-part handshake. This is ideal for a decentralized P2P environment.
-*   **`25519`:** The Diffie-Hellman function used is Curve25519.
-*   **`ChaChaPoly`:** The AEAD (Authenticated Encryption with Associated Data) cipher is ChaCha20-Poly1305.
-*   **`SHA256`:** The hash function used for all cryptographic hashing operations is SHA-256.
+Public broadcast messages are cached (1000 packets) and reconciled between peers every ~15 s using compact GCS filters: each side advertises what it holds, the other returns what is missing. Messages stay sync-able for **6 hours** and the cache persists to disk, so a device that walks between two partitions — or relaunches later — serves the room's recent history to whoever missed it. Fragments and file transfers keep a short 15-minute window.
 
-### 5.2. The `XX` Handshake
+### 6.4 Nostr Mailboxes
 
-The `XX` handshake consists of three messages exchanged between an Initiator and a Responder to establish a shared secret and derive transport encryption keys.
+Gift-wrapped messages rest on Nostr relays; clients re-subscribe with a 24-hour lookback on reconnect, covering the both-devices-offline case for mutual favorites whenever either side touches the internet.
 
-```mermaid
-sequenceDiagram
-    participant I as Initiator
-    participant R as Responder
+### 6.5 Delivery Metrics
 
-    Note over I, R: Pre-computation: h = SHA256(protocol_name)
+Bare local counters (deposits, handovers, sprays, opens, outbox flushes and drops — no identities, message IDs, or timestamps) let delivery behavior be measured on-device. They never leave the device and are cleared by the panic wipe.
 
-    I->>R: -> e
-    Note right of I: I generates ephemeral key `e_i`.<br/>h = SHA256(h + e_i.pub)
+## 7. Application Layer
 
-    R->>I: <- e, ee, s, es
-    Note left of R: R generates ephemeral key `e_r`.<br/>h = SHA256(h + e_r.pub)<br/>MixKey(DH(e_i, e_r))<br/>R sends static key `s_r`, encrypted.<br/>h = SHA256(h + ciphertext)<br/>MixKey(DH(e_i, s_r))
-
-    I->>R: -> s, se
-    Note right of I: I decrypts and verifies `s_r`.<br/>I sends static key `s_i`, encrypted.<br/>h = SHA256(h + ciphertext)<br/>MixKey(DH(s_i, e_r))
-
-    Note over I, R: Handshake complete. Transport keys derived.
-```
-
-**Handshake Flow:**
-
-1.  **Initiator -> Responder:** The initiator generates a new ephemeral key pair (`e_i`) and sends the public part to the responder.
-2.  **Responder -> Initiator:** The responder receives the initiator's ephemeral public key. It then generates its own ephemeral key pair (`e_r`), performs a DH exchange with the initiator's ephemeral key (`ee`), sends its own static public key (`s_r`) encrypted with the resulting symmetric key, and performs another DH exchange between the initiator's ephemeral key and its own static key (`es`).
-3.  **Initiator -> Responder:** The initiator receives the responder's message, decrypts the responder's static key, and authenticates it. The initiator then sends its own static key (`s_i`) encrypted and performs a final DH exchange between its static key and the responder's ephemeral key (`se`).
-
-Upon completion, both parties share a set of symmetric keys for bidirectional transport message encryption. The final handshake hash is used for channel binding.
-
-### 5.3. Session Management
-
-The `NoiseSessionManager` class manages all active Noise sessions. It handles:
-*   Creating sessions for new peers.
-*   Coordinating the handshake process to prevent race conditions.
-*   Storing the resulting transport ciphers (`sendCipher`, `receiveCipher`).
-*   Periodically checking if sessions need to be re-keyed for enhanced security.
-
----
-
-## 6. The BitChat Session and Application Protocol
-
-Once a Noise session is established, peers exchange `BitchatPacket` structures, which are encrypted as the payload of Noise transport messages.
-
-### 6.1. Binary Packet Format (`BitchatPacket`)
-
-To minimize bandwidth, `BitchatPacket`s are serialized into a compact binary format. The structure is designed to be fixed-size where possible to resist traffic analysis.
-
-| Field           | Size (bytes) | Description                                                                                             |
-|-----------------|--------------|---------------------------------------------------------------------------------------------------------|
-| **Header**      | **13**       | **Fixed-size header**                                                                                   |
-| Version         | 1            | Protocol version (currently `1`).                                                                       |
-| Type            | 1            | Message type (e.g., `message`, `deliveryAck`, `noiseHandshakeInit`). See `MessageType` enum.            |
-| TTL             | 1            | Time-To-Live for mesh network routing. Decremented at each hop.                                         |
-| Timestamp       | 8            | `UInt64` millisecond timestamp of packet creation.                                                      |
-| Flags           | 1            | Bitmask for optional fields (`hasRecipient`, `hasSignature`, `isCompressed`).                           |
-| Payload Length  | 2            | `UInt16` length of the payload field.                                                                   |
-| **Variable**    | **...**      | **Variable-size fields**                                                                                |
-| Sender ID       | 8            | 8-byte truncated peer ID of the sender.                                                                 |
-| Recipient ID    | 8 (optional) | 8-byte truncated peer ID of the recipient. Present if `hasRecipient` flag is set. Broadcast if `0xFF..FF`. |
-| Payload         | Variable     | The actual content of the packet, as defined by the `Type` field.                                       |
-| Signature       | 64 (optional)| `Ed25519` signature of the packet. Present if `hasSignature` flag is set.                               |
-
-**Padding:** All packets are padded to the next standard block size (256, 512, 1024, or 2048 bytes) using a PKCS#7-style scheme to obscure the true message length from network observers.
-
-### 6.2. Application Message Format (`BitchatMessage`)
-
-For packets of type `message`, the payload is a binary-serialized `BitchatMessage` containing the chat content.
-
-| Field               | Size (bytes) | Description                                                              |
-|---------------------|--------------|--------------------------------------------------------------------------|
-| Flags               | 1            | Bitmask for optional fields (`isRelay`, `isPrivate`, `hasOriginalSender`). |
-| Timestamp           | 8            | `UInt64` millisecond timestamp of message creation.                      |
-| ID                  | 1 + len      | `UUID` string for the message.                                           |
-| Sender              | 1 + len      | Nickname of the sender.                                                  |
-| Content             | 2 + len      | The UTF-8 encoded message content.                                       |
-| Original Sender     | 1 + len (opt)| Nickname of the original sender if the message is a relay.               |
-| Recipient Nickname  | 1 + len (opt)| Nickname of the recipient for private messages.                          |
-
----
-
-## 7. Message Routing and Propagation
-
-BitChat operates as a decentralized mesh network, meaning there are no central servers to route messages. Packets are propagated through the network from peer to peer. The protocol supports several modes of message delivery.
-
-### 7.1. Direct Connection
-
-This is the simplest case. If Peer A and Peer B are directly connected, they can exchange packets after establishing a mutually authenticated Noise session. All packets are encrypted using the transport ciphers derived from the handshake.
-
-### 7.2. Efficient Gossip with Bloom Filters
-
-To send messages to peers that are not directly connected, BitChat employs a "flooding" or "gossip" protocol. When a peer receives a packet that is not destined for it, it acts as a relay. To prevent infinite routing loops and minimize memory usage, the protocol uses an `OptimizedBloomFilter` to track recently seen packet IDs.
-
-The logic is as follows:
-
-1.  A peer receives a packet.
-2.  It checks the Bloom filter to see if the packet's ID has likely been seen before. If so, the packet is discarded. Bloom filters can have false positives (though they are rare), but they guarantee no false negatives. This means a new packet will never be accidentally discarded.
-3.  If the packet is new, its ID is added to the Bloom filter.
-4.  The peer decrements the packet's Time-To-Live (TTL) field.
-5.  If the TTL is greater than zero, the peer re-broadcasts the packet to all of its connected peers, *except* for the peer from which it received the packet.
-
-This mechanism allows packets to "flood" through the network efficiently, maximizing the chance of reaching their destination while using minimal resources to prevent loops.
-
-### 7.3. Time-To-Live (TTL)
-
-Every `BitchatPacket` contains an 8-bit TTL field. This value is set by the originating peer and is decremented by one at each relay hop. If a peer receives a packet and decrements its TTL to 0, it will process the packet (if it is the recipient) but will not relay it further. This is a crucial mechanism to prevent packets from circulating endlessly in the mesh.
-
-### 7.4. Private vs. Broadcast Messages
-
-The routing logic respects the confidentiality of private messages:
-
-*   **Private Messages:** A packet with a specific `recipientID` is a private message. Relay nodes forward the entire, encrypted Noise message without being able to access the inner `BitchatPacket` or its payload. Only the final recipient, who shares the correct Noise session keys with the sender, can decrypt the packet.
-*   **Broadcast Messages:** A packet with the special broadcast `recipientID` (`0xFFFFFFFFFFFFFFFF`) is intended for all peers. Any peer that receives and decrypts a broadcast message will process its content. It will still be relayed according to the flooding algorithm to ensure it reaches the entire network.
-
-### 7.5. Message Reliability and Lifecycle
-
-To function in unreliable, lossy networks, the protocol includes features to track the lifecycle of a message and ensure its delivery.
-
-*   **Delivery Acknowledgments (`DeliveryAck`):** When a private message reaches its final destination, the recipient's device sends a `DeliveryAck` packet back to the original sender. This acknowledgment contains the ID of the original message.
-*   **Read Receipts (`ReadReceipt`):** After a message is displayed on the recipient's screen, the application can send a `ReadReceipt`, also containing the original message ID, to inform the sender that the message has been seen.
-*   **Message Retry Service:** Senders maintain a `MessageRetryService` which tracks outgoing messages. If a `DeliveryAck` is not received for a message within a certain time window, the service will automatically re-send the message, creating a more resilient user experience.
-
-### 7.6. Fragmentation
-
-Transport layers like BLE have a Maximum Transmission Unit (MTU) that limits the size of a single packet. To handle messages larger than this limit, BitChat implements a fragmentation protocol.
-
-*   **`fragmentStart`:** A packet with this type marks the beginning of a fragmented message. It contains metadata about the total size and number of fragments.
-*   **`fragmentContinue`:** These packets carry the intermediate chunks of the message data.
-*   **`fragmentEnd`:** This packet carries the final chunk of the message and signals the receiver to begin reassembly.
-
-Receiving peers collect all fragments and reassemble them in the correct order before passing the complete message up to the application layer.
-
----
+* **Public chat** — signed broadcast messages within the mesh, backed by the gossip-synced history above.
+* **Private chat** — end-to-end encrypted messages with delivery and read receipts, over mesh, courier, or Nostr.
+* **Location channels** — geohash-scoped public rooms carried over Nostr relays for regional chat beyond radio range.
+* **Favorites** — the mutual-trust relationship that unlocks Nostr delivery and the larger courier quota.
+* **Media** — files and images fragment over the mesh (1 MiB cap, explicit accept before anything touches disk); couriers carry text only.
+* **Panic wipe** — clears identity keys, favorites, carried courier mail, the sealed outbox, archived public history, and metrics.
 
 ## 8. Security Considerations
 
-*   **Replay Attacks:** The Noise transport messages include a nonce that is incremented for each message. The `NoiseCipherState` implements a sliding window replay protection mechanism to detect and discard replayed or out-of-order messages.
-*   **Denial of Service:** The `NoiseRateLimiter` is implemented to prevent resource exhaustion from rapid, repeated handshake attempts from a single peer.
-*   **Key-Compromise Impersonation:** The `XX` pattern authenticates both parties, preventing an attacker from impersonating one party to the other.
-*   **Identity Binding:** While the Noise handshake authenticates the cryptographic keys, binding those keys to a human-readable nickname is handled at the application layer. Users must verify fingerprints out-of-band to prevent man-in-the-middle attacks.
-*   **Traffic Analysis:** The use of fixed-size padding for all packets helps to obscure the exact nature and content of the communication, making it harder for a network-level adversary to infer information based on message size.
+* **Relay nodes** cannot read private traffic; they forward padded, opaque ciphertext.
+* **Couriers** are quota-bounded mailbags. A malicious courier can drop mail (redundant copies and deposit retry mitigate this) but cannot read it, link it across days, or amplify it — copy budgets are capped and every envelope is validated against size and lifetime policy on deposit.
+* **Flooding abuse** is bounded by TTL clamps, deduplication, per-depositor quotas, connect-rate limits, and announce-rate limiting.
+* **Replay** of public broadcasts is bounded by the 6-hour acceptance window plus deduplication; private payloads are protected by Noise nonces.
+* **Metadata.** BLE proximity is inherently observable; ephemeral IDs and daily-rotating courier tags limit long-term correlation. Nostr traffic can ride Tor.
+* **No forward secrecy for sealed mail** (§5.2) is the main cryptographic trade-off of the offline path.
+
+## 9. Future Work
+
+* Prekey-based forward secrecy for courier envelopes.
+* Couriered media beyond the 16 KiB text cap.
+* Probabilistic relay and edge-of-network TTL boosting for very dense and very sparse graphs.
+* Multi-hop courier routing informed by encounter history.
 
 ---
 
-## 9. Conclusion
-
-The BitChat Protocol provides a robust and secure foundation for decentralized, peer-to-peer communication. By layering a flexible application protocol on top of the well-regarded Noise Protocol Framework, it achieves strong confidentiality, authentication, and forward secrecy. The use of a compact binary format and thoughtful security considerations like rate limiting and traffic analysis resistance make it suitable for use in challenging network environments.
+*This document describes the protocol as implemented in the current release. The implementation is free and unencumbered software released into the public domain.*

bitchat.xcodeproj/xcshareddata/xcschemes/bitchat (iOS).xcscheme

@@ -0,0 +1,131 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "2650"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "57CA17A36A2532A6CFF367BB"
+               BuildableName = "bitchatShareExtension.appex"
+               BlueprintName = "bitchatShareExtension"
+               ReferencedContainer = "container:bitchat.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "AF077EA0474EDEDE2C72716C"
+               BuildableName = "bitchat.app"
+               BlueprintName = "bitchat_iOS"
+               ReferencedContainer = "container:bitchat.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      codeCoverageEnabled = "YES"
+      onlyGenerateCoverageForSpecifiedTargets = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "AF077EA0474EDEDE2C72716C"
+            BuildableName = "bitchat.app"
+            BlueprintName = "bitchat_iOS"
+            ReferencedContainer = "container:bitchat.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+      <CodeCoverageTargets>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "AF077EA0474EDEDE2C72716C"
+            BuildableName = "bitchat.app"
+            BlueprintName = "bitchat_iOS"
+            ReferencedContainer = "container:bitchat.xcodeproj">
+         </BuildableReference>
+      </CodeCoverageTargets>
+      <Testables>
+         <TestableReference
+            skipped = "NO"
+            parallelizable = "YES"
+            testExecutionOrdering = "random">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "6CB97DF2EA57234CB3E563B8"
+               BuildableName = "bitchatTests_iOS.xctest"
+               BlueprintName = "bitchatTests_iOS"
+               ReferencedContainer = "container:bitchat.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "AF077EA0474EDEDE2C72716C"
+            BuildableName = "bitchat.app"
+            BlueprintName = "bitchat_iOS"
+            ReferencedContainer = "container:bitchat.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+      <EnvironmentVariables>
+         <EnvironmentVariable
+            key = "BITCHAT_LOG_LEVEL"
+            value = "debug"
+            isEnabled = "YES">
+         </EnvironmentVariable>
+      </EnvironmentVariables>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "AF077EA0474EDEDE2C72716C"
+            BuildableName = "bitchat.app"
+            BlueprintName = "bitchat_iOS"
+            ReferencedContainer = "container:bitchat.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

bitchat.xcodeproj/xcshareddata/xcschemes/bitchat (macOS).xcscheme

@@ -0,0 +1,105 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "2650"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "0576A29205865664C0937536"
+               BuildableName = "bitchat.app"
+               BlueprintName = "bitchat_macOS"
+               ReferencedContainer = "container:bitchat.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "0576A29205865664C0937536"
+            BuildableName = "bitchat.app"
+            BlueprintName = "bitchat_macOS"
+            ReferencedContainer = "container:bitchat.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+      <Testables>
+         <TestableReference
+            skipped = "NO"
+            parallelizable = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "47FF23248747DD7CB666CB91"
+               BuildableName = "bitchatTests_macOS.xctest"
+               BlueprintName = "bitchatTests_macOS"
+               ReferencedContainer = "container:bitchat.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "0576A29205865664C0937536"
+            BuildableName = "bitchat.app"
+            BlueprintName = "bitchat_macOS"
+            ReferencedContainer = "container:bitchat.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+      <EnvironmentVariables>
+         <EnvironmentVariable
+            key = "BITCHAT_LOG_LEVEL"
+            value = "debug"
+            isEnabled = "YES">
+         </EnvironmentVariable>
+      </EnvironmentVariables>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "0576A29205865664C0937536"
+            BuildableName = "bitchat.app"
+            BlueprintName = "bitchat_macOS"
+            ReferencedContainer = "container:bitchat.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

bitchat/App/AppArchitecture.swift

@@ -0,0 +1,102 @@
+import BitFoundation
+import Combine
+import Foundation
+
+enum SharedContentKind: String, Sendable, Equatable {
+    case text
+    case url
+}
+
+enum RuntimeScenePhase: String, Sendable, Equatable {
+    case active
+    case inactive
+    case background
+}
+
+enum TorLifecycleEvent: String, Sendable, Equatable {
+    case willStart
+    case willRestart
+    case didBecomeReady
+    case preferenceChanged
+}
+
+enum AppEvent: Sendable, Equatable {
+    case launched
+    case startupCompleted
+    case scenePhaseChanged(RuntimeScenePhase)
+    case openedURL(String)
+    case sharedContentAccepted(SharedContentKind)
+    case notificationOpened(peerID: PeerID?)
+    case deepLinkOpened(String)
+    case torLifecycleChanged(TorLifecycleEvent)
+    case nostrRelayConnectionChanged(Bool)
+    case terminationRequested
+}
+
+actor AppEventStream {
+    private var continuations: [UUID: AsyncStream<AppEvent>.Continuation] = [:]
+
+    func stream() -> AsyncStream<AppEvent> {
+        let id = UUID()
+        return AsyncStream { continuation in
+            continuations[id] = continuation
+            continuation.onTermination = { [id] _ in
+                Task {
+                    await self.removeContinuation(id)
+                }
+            }
+        }
+    }
+
+    func emit(_ event: AppEvent) {
+        for continuation in continuations.values {
+            continuation.yield(event)
+        }
+    }
+
+    func finish() {
+        for continuation in continuations.values {
+            continuation.finish()
+        }
+        continuations.removeAll()
+    }
+
+    private func removeContinuation(_ id: UUID) {
+        continuations.removeValue(forKey: id)
+    }
+}
+
+/// Identity key for a direct conversation. Equality and hashing use the
+/// canonical `id` only; `routingPeerID` carries the transport-level peer ID
+/// the conversation is keyed under (see `ConversationID.directPeer`).
+struct PeerHandle: Sendable, Identifiable {
+    let id: String
+    let routingPeerID: PeerID
+}
+
+extension PeerHandle: Equatable {
+    static func == (lhs: PeerHandle, rhs: PeerHandle) -> Bool {
+        lhs.id == rhs.id
+    }
+}
+
+extension PeerHandle: Hashable {
+    func hash(into hasher: inout Hasher) {
+        hasher.combine(id)
+    }
+}
+
+enum ConversationID: Hashable, Sendable {
+    case mesh
+    case geohash(String)
+    case direct(PeerHandle)
+
+    init(channelID: ChannelID) {
+        switch channelID {
+        case .mesh:
+            self = .mesh
+        case .location(let channel):
+            self = .geohash(channel.geohash.lowercased())
+        }
+    }
+}

bitchat/App/AppChromeModel.swift

@@ -0,0 +1,125 @@
+import BitFoundation
+import Combine
+import CoreBluetooth
+import Foundation
+
+@MainActor
+final class AppChromeModel: ObservableObject {
+    @Published private(set) var hasUnreadPrivateMessages = false
+    @Published var nickname: String
+    @Published var showingFingerprintFor: PeerID?
+    @Published var isAppInfoPresented = false
+    @Published var isLocationChannelsSheetPresented = false
+    @Published var showBluetoothAlert = false
+    @Published var bluetoothAlertMessage = ""
+    @Published var bluetoothState: CBManagerState = .unknown
+    @Published var showScreenshotPrivacyWarning = false
+
+    private let chatViewModel: ChatViewModel
+    private var cancellables = Set<AnyCancellable>()
+
+    /// Bulletin-board coordinator, created on first use of the board sheet.
+    private(set) lazy var boardManager = BoardManager(transport: chatViewModel.meshService)
+
+    init(chatViewModel: ChatViewModel, privateInboxModel: PrivateInboxModel) {
+        self.chatViewModel = chatViewModel
+        self.nickname = chatViewModel.nickname
+
+        bind(privateInboxModel: privateInboxModel)
+    }
+
+    var shouldSuppressScreenshotNotification: Bool {
+        isLocationChannelsSheetPresented || isAppInfoPresented
+    }
+
+    func setNickname(_ nickname: String) {
+        self.nickname = nickname
+        if chatViewModel.nickname != nickname {
+            chatViewModel.nickname = nickname
+        }
+    }
+
+    func validateAndSaveNickname() {
+        chatViewModel.validateAndSaveNickname()
+        if nickname != chatViewModel.nickname {
+            nickname = chatViewModel.nickname
+        }
+    }
+
+    func openMostRelevantPrivateChat() {
+        chatViewModel.openMostRelevantPrivateChat()
+    }
+
+    func showFingerprint(for peerID: PeerID) {
+        showingFingerprintFor = peerID
+    }
+
+    func clearFingerprint() {
+        showingFingerprintFor = nil
+    }
+
+    func presentAppInfo() {
+        isAppInfoPresented = true
+    }
+
+    /// Builds the mesh topology map model from the transport's gossiped
+    /// graph plus the live nickname table. Unknown nodes (heard about via a
+    /// neighbor claim but never announced to us) fall back to a short ID.
+    func meshTopologyDisplayModel() -> MeshTopologyDisplayModel {
+        let mesh = chatViewModel.meshService
+        guard let snapshot = mesh.currentMeshTopology() else { return .empty }
+        let nicknames = mesh.getPeerNicknames()
+
+        let nodes = snapshot.nodes.map { peerID -> MeshTopologyDisplayModel.Node in
+            let isSelf = peerID == snapshot.localPeerID
+            let label: String
+            if isSelf {
+                label = chatViewModel.nickname
+            } else {
+                label = nicknames[peerID] ?? "\(peerID.id.prefix(8))…"
+            }
+            return MeshTopologyDisplayModel.Node(id: peerID.id, label: label, isSelf: isSelf)
+        }
+        let edges = snapshot.edges.map { ($0.a.id, $0.b.id) }
+        return MeshTopologyDisplayModel(nodes: nodes, edges: edges)
+    }
+
+    func triggerScreenshotPrivacyWarning() {
+        showScreenshotPrivacyWarning = true
+    }
+
+    func panicClearAllData() {
+        chatViewModel.panicClearAllData()
+    }
+
+    private func bind(privateInboxModel: PrivateInboxModel) {
+        privateInboxModel.$unreadPeerIDs
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] unreadPeerIDs in
+                self?.hasUnreadPrivateMessages = !unreadPeerIDs.isEmpty
+            }
+            .store(in: &cancellables)
+
+        chatViewModel.$nickname
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] nickname in
+                guard let self, self.nickname != nickname else { return }
+                self.nickname = nickname
+            }
+            .store(in: &cancellables)
+
+        chatViewModel.$showBluetoothAlert
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$showBluetoothAlert)
+
+        chatViewModel.$bluetoothAlertMessage
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$bluetoothAlertMessage)
+
+        chatViewModel.$bluetoothState
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$bluetoothState)
+
+        hasUnreadPrivateMessages = !privateInboxModel.unreadPeerIDs.isEmpty
+    }
+}

bitchat/App/AppRuntime.swift

@@ -0,0 +1,388 @@
+import BitFoundation
+import Combine
+import Foundation
+import SwiftUI
+import Tor
+import UserNotifications
+#if os(iOS)
+import UIKit
+#elseif os(macOS)
+import AppKit
+#endif
+
+@MainActor
+final class AppRuntime: ObservableObject {
+    let chatViewModel: ChatViewModel
+    let events = AppEventStream()
+    /// Single source of truth for conversation message state and selection
+    /// (docs/CONVERSATION-STORE-DESIGN.md). Owned here; the feature models
+    /// and `ChatViewModel` observe and mutate it through its intent API.
+    let conversations: ConversationStore
+    let peerIdentityStore: PeerIdentityStore
+    let locationPresenceStore: LocationPresenceStore
+    let publicChatModel: PublicChatModel
+    let privateInboxModel: PrivateInboxModel
+    let privateConversationModel: PrivateConversationModel
+    let verificationModel: VerificationModel
+    let conversationUIModel: ConversationUIModel
+    let locationChannelsModel: LocationChannelsModel
+    let peerListModel: PeerListModel
+    let appChromeModel: AppChromeModel
+
+    private let idBridge: NostrIdentityBridge
+    private var cancellables = Set<AnyCancellable>()
+    private var started = false
+    private var lastNostrRelayConnectedState = false
+    private var didHandleInitialNostrConnection = false
+
+    #if os(iOS)
+    private var didHandleInitialActive = false
+    private var didEnterBackground = false
+    #endif
+
+    init(
+        keychain: KeychainManagerProtocol = KeychainManager(),
+        idBridge: NostrIdentityBridge = NostrIdentityBridge()
+    ) {
+        self.idBridge = idBridge
+        let conversations = ConversationStore()
+        let peerIdentityStore = PeerIdentityStore()
+        let locationPresenceStore = LocationPresenceStore()
+        let locationManager = LocationChannelManager.shared
+        self.conversations = conversations
+        self.peerIdentityStore = peerIdentityStore
+        self.locationPresenceStore = locationPresenceStore
+        self.chatViewModel = ChatViewModel(
+            keychain: keychain,
+            idBridge: idBridge,
+            identityManager: SecureIdentityStateManager(keychain),
+            conversations: conversations,
+            peerIdentityStore: peerIdentityStore,
+            locationPresenceStore: locationPresenceStore,
+            locationManager: locationManager
+        )
+        self.publicChatModel = PublicChatModel(conversations: conversations)
+        self.privateInboxModel = PrivateInboxModel(conversations: conversations)
+        self.locationChannelsModel = LocationChannelsModel(manager: locationManager)
+        self.privateConversationModel = PrivateConversationModel(
+            chatViewModel: self.chatViewModel,
+            conversations: conversations,
+            locationChannelsModel: self.locationChannelsModel,
+            peerIdentityStore: peerIdentityStore
+        )
+        self.verificationModel = VerificationModel(
+            chatViewModel: self.chatViewModel,
+            privateConversationModel: self.privateConversationModel,
+            peerIdentityStore: peerIdentityStore
+        )
+        self.conversationUIModel = ConversationUIModel(
+            chatViewModel: self.chatViewModel,
+            privateConversationModel: self.privateConversationModel,
+            conversations: conversations
+        )
+        self.peerListModel = PeerListModel(
+            chatViewModel: self.chatViewModel,
+            conversations: conversations,
+            locationChannelsModel: self.locationChannelsModel,
+            peerIdentityStore: peerIdentityStore,
+            locationPresenceStore: locationPresenceStore
+        )
+        self.appChromeModel = AppChromeModel(
+            chatViewModel: self.chatViewModel,
+            privateInboxModel: self.privateInboxModel
+        )
+
+        GeoRelayDirectory.shared.prefetchIfNeeded()
+        bindRuntimeObservers()
+        NotificationDelegate.shared.runtime = self
+    }
+
+    func start() {
+        guard !started else {
+            checkForSharedContent()
+            return
+        }
+
+        started = true
+        NotificationDelegate.shared.runtime = self
+        VerificationService.shared.configure(with: chatViewModel.meshService)
+        announceInitialTorStatusIfNeeded()
+
+        Task(priority: .utility) { [weak self] in
+            guard let self else { return }
+            let nickname = await MainActor.run { self.chatViewModel.nickname }
+            let npub = await MainActor.run {
+                try? self.idBridge.getCurrentNostrIdentity()?.npub
+            }
+            await MainActor.run {
+                _ = VerificationService.shared.buildMyQRString(nickname: nickname, npub: npub)
+            }
+        }
+
+        NetworkActivationService.shared.start()
+        GeohashPresenceService.shared.start()
+        checkForSharedContent()
+
+        record(.launched)
+        record(.startupCompleted)
+    }
+
+    func handleOpenURL(_ url: URL) {
+        record(.openedURL(url.absoluteString))
+
+        if url.scheme == "bitchat", url.host == "share" {
+            checkForSharedContent()
+        }
+    }
+
+    func handleDidBecomeActiveNotification() {
+        chatViewModel.handleDidBecomeActive()
+        checkForSharedContent()
+    }
+
+    #if os(macOS)
+    func handleMacDidBecomeActiveNotification() {
+        record(.scenePhaseChanged(.active))
+        chatViewModel.handleDidBecomeActive()
+        checkForSharedContent()
+    }
+    #endif
+
+    #if os(iOS)
+    func handleScenePhaseChange(_ newPhase: ScenePhase) {
+        switch newPhase {
+        case .background:
+            record(.scenePhaseChanged(.background))
+            TorManager.shared.setAppForeground(false)
+            TorManager.shared.goDormantOnBackground()
+            chatViewModel.endGeohashSampling()
+            NostrRelayManager.shared.disconnect()
+            didEnterBackground = true
+
+        case .active:
+            record(.scenePhaseChanged(.active))
+            chatViewModel.meshService.startServices()
+            TorManager.shared.setAppForeground(true)
+            let shouldRefreshNostrConnections = didHandleInitialActive && didEnterBackground
+
+            if didHandleInitialActive && didEnterBackground {
+                if TorManager.shared.isAutoStartAllowed() && !TorManager.shared.isReady {
+                    TorManager.shared.ensureRunningOnForeground()
+                }
+            } else {
+                didHandleInitialActive = true
+            }
+
+            didEnterBackground = false
+
+            if shouldRefreshNostrConnections && TorManager.shared.isAutoStartAllowed() {
+                Task.detached {
+                    let _ = await TorManager.shared.awaitReady(timeout: 60)
+                    await MainActor.run {
+                        TorURLSession.shared.rebuild()
+                        NostrRelayManager.shared.resetAllConnections()
+                    }
+                }
+            }
+
+            chatViewModel.handleDidBecomeActive()
+            checkForSharedContent()
+
+        case .inactive:
+            record(.scenePhaseChanged(.inactive))
+
+        @unknown default:
+            break
+        }
+    }
+    #endif
+
+    func applicationWillTerminate() {
+        record(.terminationRequested)
+        chatViewModel.applicationWillTerminate()
+    }
+
+    func handleNotificationResponse(identifier: String, userInfo: [AnyHashable: Any]) {
+        if identifier.hasPrefix("private-"), let peerID = PeerID(str: userInfo["peerID"] as? String) {
+            record(.notificationOpened(peerID: peerID))
+            chatViewModel.startPrivateChat(with: peerID)
+        }
+
+        if let deepLink = userInfo["deeplink"] as? String, let url = URL(string: deepLink) {
+            record(.deepLinkOpened(deepLink))
+            openExternalURL(url)
+        }
+    }
+
+    func presentationOptions(
+        forNotificationIdentifier identifier: String,
+        userInfo: [AnyHashable: Any]
+    ) async -> UNNotificationPresentationOptions {
+        if identifier.hasPrefix("private-"), let peerID = PeerID(str: userInfo["peerID"] as? String) {
+            if conversations.selectedPrivatePeerID == peerID {
+                return []
+            }
+            return [.banner, .sound]
+        }
+
+        if identifier.hasPrefix("geo-activity-"),
+           let deepLink = userInfo["deeplink"] as? String,
+           let geohash = deepLink.components(separatedBy: "/").last,
+           case .location(let channel) = locationChannelsModel.selectedChannel,
+           channel.geohash == geohash {
+            return []
+        }
+
+        return [.banner, .sound]
+    }
+}
+
+private extension AppRuntime {
+    func bindRuntimeObservers() {
+        NostrRelayManager.shared.$isConnected
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] isConnected in
+                self?.handleNostrRelayConnectionChanged(isConnected)
+            }
+            .store(in: &cancellables)
+
+        NotificationCenter.default.publisher(for: .TorWillRestart)
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.record(.torLifecycleChanged(.willRestart))
+                self?.chatViewModel.handleTorWillRestart()
+            }
+            .store(in: &cancellables)
+
+        NotificationCenter.default.publisher(for: .TorDidBecomeReady)
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.record(.torLifecycleChanged(.didBecomeReady))
+                self?.chatViewModel.handleTorDidBecomeReady()
+            }
+            .store(in: &cancellables)
+
+        NotificationCenter.default.publisher(for: .TorWillStart)
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.record(.torLifecycleChanged(.willStart))
+                self?.chatViewModel.handleTorWillStart()
+            }
+            .store(in: &cancellables)
+
+        NotificationCenter.default.publisher(for: .TorUserPreferenceChanged)
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] notification in
+                self?.record(.torLifecycleChanged(.preferenceChanged))
+                self?.chatViewModel.handleTorPreferenceChanged(notification)
+            }
+            .store(in: &cancellables)
+
+        #if os(iOS)
+        NotificationCenter.default.publisher(for: UIApplication.userDidTakeScreenshotNotification)
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.handleScreenshotCaptured()
+            }
+            .store(in: &cancellables)
+        #endif
+    }
+
+    func checkForSharedContent() {
+        guard let userDefaults = UserDefaults(suiteName: BitchatApp.groupID),
+              let sharedContent = userDefaults.string(forKey: "sharedContent"),
+              let sharedDate = userDefaults.object(forKey: "sharedContentDate") as? Date else {
+            return
+        }
+
+        guard Date().timeIntervalSince(sharedDate) < TransportConfig.uiShareAcceptWindowSeconds else {
+            return
+        }
+
+        let contentKind = SharedContentKind(rawValue: userDefaults.string(forKey: "sharedContentType") ?? "") ?? .text
+
+        userDefaults.removeObject(forKey: "sharedContent")
+        userDefaults.removeObject(forKey: "sharedContentType")
+        userDefaults.removeObject(forKey: "sharedContentDate")
+
+        switch contentKind {
+        case .url:
+            if let data = sharedContent.data(using: .utf8),
+               let urlData = try? JSONSerialization.jsonObject(with: data) as? [String: String],
+               let url = urlData["url"] {
+                chatViewModel.sendMessage(url)
+            } else {
+                chatViewModel.sendMessage(sharedContent)
+            }
+        case .text:
+            chatViewModel.sendMessage(sharedContent)
+        }
+
+        record(.sharedContentAccepted(contentKind))
+    }
+
+    func handleNostrRelayConnectionChanged(_ isConnected: Bool) {
+        record(.nostrRelayConnectionChanged(isConnected))
+
+        let becameConnected = isConnected && !lastNostrRelayConnectedState
+        lastNostrRelayConnectedState = isConnected
+
+        guard started, becameConnected else { return }
+
+        let isInitialConnection = !didHandleInitialNostrConnection
+        didHandleInitialNostrConnection = true
+
+        if !chatViewModel.nostrHandlersSetup {
+            chatViewModel.setupNostrMessageHandling()
+            chatViewModel.nostrHandlersSetup = true
+        }
+
+        guard !isInitialConnection else { return }
+
+        chatViewModel.resubscribeCurrentGeohash()
+        chatViewModel.geoChannelCoordinator?.refreshSampling()
+    }
+
+    func announceInitialTorStatusIfNeeded() {
+        if TorManager.shared.torEnforced &&
+            !chatViewModel.torStatusAnnounced &&
+            TorManager.shared.isAutoStartAllowed() {
+            chatViewModel.torStatusAnnounced = true
+            chatViewModel.addGeohashOnlySystemMessage(
+                String(localized: "system.tor.starting", comment: "System message when Tor is starting")
+            )
+        } else if !TorManager.shared.torEnforced && !chatViewModel.torStatusAnnounced {
+            chatViewModel.torStatusAnnounced = true
+            chatViewModel.addGeohashOnlySystemMessage(
+                String(localized: "system.tor.dev_bypass", comment: "System message when Tor bypass is enabled in development")
+            )
+        }
+    }
+
+    func handleScreenshotCaptured() {
+        if appChromeModel.isLocationChannelsSheetPresented {
+            appChromeModel.triggerScreenshotPrivacyWarning()
+            return
+        }
+
+        if appChromeModel.isAppInfoPresented {
+            return
+        }
+
+        chatViewModel.handleScreenshotCaptured()
+    }
+
+    func openExternalURL(_ url: URL) {
+        #if os(iOS)
+        UIApplication.shared.open(url)
+        #else
+        NSWorkspace.shared.open(url)
+        #endif
+    }
+
+    func record(_ event: AppEvent) {
+        Task {
+            await events.emit(event)
+        }
+    }
+}

bitchat/App/ConversationStore.swift

@@ -0,0 +1,918 @@
+//
+// ConversationStore.swift
+// bitchat
+//
+// Single source of truth for conversation message state (see
+// docs/CONVERSATION-STORE-DESIGN.md). One `Conversation` object per
+// `ConversationID`; all mutations flow through the store's intent API and
+// every mutation emits a `ConversationChange` after state is consistent.
+//
+// The store also owns conversation selection: the active public channel and
+// the selected private peer (the two UI selection axes) plus the derived
+// `selectedConversationID`.
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import BitFoundation
+import BitLogger
+import Combine
+import Foundation
+
+// MARK: - Conversation
+
+/// A single conversation timeline (`.mesh`, `.geohash`, or `.direct`).
+///
+/// Publishing granularity is per conversation: views observe ONE
+/// `Conversation` object, so an append to chat A never invalidates observers
+/// of chat B.
+///
+/// Mutations are `fileprivate` by design — only `ConversationStore`'s intent
+/// API may mutate a conversation, keeping the store the sole writer.
+@MainActor
+final class Conversation: ObservableObject, Identifiable {
+    let id: ConversationID
+    /// Maximum retained messages; oldest are trimmed on overflow.
+    let cap: Int
+
+    @Published private(set) var messages: [BitchatMessage] = []
+    @Published private(set) var isUnread: Bool = false
+
+    /// Incrementally-maintained message-ID → index map for O(1) dedup and
+    /// delivery-status lookup. Kept in sync on every mutation:
+    /// - tail append: single insert
+    /// - out-of-order insert: suffix reindex from the insertion point
+    /// - trim: full rebuild — `removeFirst(k)` is already O(n), so the
+    ///   rebuild does not change the asymptotics, and trim only happens once
+    ///   the cap (1337) is reached. Simple and correct beats the
+    ///   offset-tracking alternative here.
+    private var indexByMessageID: [String: Int] = [:]
+
+    fileprivate init(id: ConversationID, cap: Int) {
+        self.id = id
+        self.cap = max(1, cap)
+    }
+
+    // MARK: Reads
+
+    func containsMessage(withID messageID: String) -> Bool {
+        indexByMessageID[messageID] != nil
+    }
+
+    func message(withID messageID: String) -> BitchatMessage? {
+        guard let index = indexByMessageID[messageID] else { return nil }
+        return messages[index]
+    }
+
+    /// All message IDs currently in this conversation (unordered).
+    var messageIDs: Dictionary<String, Int>.Keys {
+        indexByMessageID.keys
+    }
+
+    // MARK: Store-internal mutations
+
+    /// Result of an ordered insert. `trimmedMessageIDs` reports messages
+    /// evicted by the cap so the store can keep its message-ID →
+    /// conversation map exact.
+    fileprivate struct InsertResult {
+        let inserted: Bool
+        let trimmedMessageIDs: [String]
+
+        static let duplicate = InsertResult(inserted: false, trimmedMessageIDs: [])
+    }
+
+    fileprivate enum UpsertOutcome {
+        case appended(trimmedMessageIDs: [String])
+        case updated
+    }
+
+    /// Inserts a message in timestamp order, deduplicating by message ID.
+    /// Fast path appends when the timestamp is >= the current tail;
+    /// otherwise a binary search finds the upper-bound insertion point so
+    /// arrival order is preserved among equal timestamps.
+    /// Reports `inserted: false` if a message with the same ID already exists.
+    fileprivate func insert(_ message: BitchatMessage) -> InsertResult {
+        guard indexByMessageID[message.id] == nil else { return .duplicate }
+
+        if let last = messages.last, message.timestamp < last.timestamp {
+            let index = insertionIndex(for: message.timestamp)
+            messages.insert(message, at: index)
+            reindex(from: index)
+        } else {
+            messages.append(message)
+            indexByMessageID[message.id] = messages.count - 1
+        }
+
+        return InsertResult(inserted: true, trimmedMessageIDs: trimIfNeeded())
+    }
+
+    /// Replace-or-append by message ID. An existing message keeps its
+    /// timeline position (in-place updates like media progress reuse the
+    /// original timestamp); a new message goes through ordered insertion.
+    fileprivate func upsert(_ message: BitchatMessage) -> UpsertOutcome {
+        if let index = indexByMessageID[message.id] {
+            messages[index] = message
+            return .updated
+        }
+        let result = insert(message)
+        return .appended(trimmedMessageIDs: result.trimmedMessageIDs)
+    }
+
+    /// Applies a delivery status keyed by message ID, honoring the
+    /// no-downgrade rule (the SOLE enforcement point — every delivery
+    /// update flows through the store): equal statuses are skipped, and
+    /// `.read` is never downgraded to `.delivered` or `.sent`.
+    /// Returns `true` when the status was applied.
+    fileprivate func applyDeliveryStatus(_ status: DeliveryStatus, forMessageID messageID: String) -> Bool {
+        guard let index = indexByMessageID[messageID] else { return false }
+        let message = messages[index]
+        guard !Self.shouldSkipStatusUpdate(current: message.deliveryStatus, new: status) else { return false }
+
+        message.deliveryStatus = status
+        // BitchatMessage is a reference type; write back through the
+        // subscript so the @Published wrapper emits.
+        messages[index] = message
+        return true
+    }
+
+    /// Republishes a message without changing state. Used for mirrored
+    /// copies that share a BitchatMessage instance: the first conversation's
+    /// status apply mutated the shared object, so this conversation's
+    /// observers still need an @Published emission to re-render.
+    @discardableResult
+    fileprivate func republishMessage(withID messageID: String) -> Bool {
+        guard let index = indexByMessageID[messageID] else { return false }
+        messages[index] = messages[index]
+        return true
+    }
+
+    @discardableResult
+    fileprivate func setUnread(_ unread: Bool) -> Bool {
+        guard isUnread != unread else { return false }
+        isUnread = unread
+        return true
+    }
+
+    /// Removes a single message by ID. Returns the removed message, or
+    /// `nil` when no message with that ID exists.
+    fileprivate func remove(messageID: String) -> BitchatMessage? {
+        guard let index = indexByMessageID[messageID] else { return nil }
+        let removed = messages.remove(at: index)
+        indexByMessageID.removeValue(forKey: messageID)
+        reindex(from: index)
+        return removed
+    }
+
+    /// Removes every message matching `predicate`. Returns the removed
+    /// message IDs (empty when nothing matched).
+    fileprivate func removeAll(where predicate: (BitchatMessage) -> Bool) -> [String] {
+        var removedIDs: [String] = []
+        messages.removeAll { message in
+            guard predicate(message) else { return false }
+            removedIDs.append(message.id)
+            return true
+        }
+        guard !removedIDs.isEmpty else { return [] }
+        for id in removedIDs {
+            indexByMessageID.removeValue(forKey: id)
+        }
+        reindex(from: 0)
+        return removedIDs
+    }
+
+    fileprivate func clearMessages() {
+        messages.removeAll()
+        indexByMessageID.removeAll()
+    }
+
+    // MARK: Diagnostics
+
+    /// Appends human-readable invariant violations for this conversation
+    /// (empty when healthy): the ID index must be the exact inverse of the
+    /// messages array, the cap must hold, and timestamps must be
+    /// non-decreasing (equal timestamps keep arrival order, so only strict
+    /// inversions are violations). O(messages); allocates only on violation.
+    fileprivate func collectInvariantViolations(into violations: inout [String], label: String) {
+        if indexByMessageID.count != messages.count {
+            violations.append("\(label): index has \(indexByMessageID.count) entries for \(messages.count) messages")
+        }
+        if messages.count > cap {
+            violations.append("\(label): \(messages.count) messages exceeds cap \(cap)")
+        }
+        var previousTimestamp: Date?
+        for position in messages.indices {
+            let message = messages[position]
+            // Count equality + every message resolving to its own position
+            // proves the index is exactly the inverse map (no stale extras).
+            if let index = indexByMessageID[message.id] {
+                if index != position {
+                    violations.append("\(label): message \(message.id.prefix(8))… at \(position) indexed at \(index)")
+                }
+            } else {
+                violations.append("\(label): message \(message.id.prefix(8))… at \(position) missing from index")
+            }
+            if let previousTimestamp, message.timestamp < previousTimestamp {
+                violations.append("\(label): timestamp order violated at \(position)")
+            }
+            previousTimestamp = message.timestamp
+        }
+    }
+
+    // MARK: Internals
+
+    static func shouldSkipStatusUpdate(current: DeliveryStatus?, new: DeliveryStatus) -> Bool {
+        guard let current else { return false }
+        if current == new { return true }
+
+        switch (current, new) {
+        case (.read, .delivered), (.read, .sent):
+            return true
+        default:
+            return false
+        }
+    }
+
+    /// Upper-bound binary search: first index whose timestamp is strictly
+    /// greater than `timestamp`, so equal-timestamp messages keep arrival
+    /// order.
+    private func insertionIndex(for timestamp: Date) -> Int {
+        var low = 0
+        var high = messages.count
+        while low < high {
+            let mid = (low + high) / 2
+            if messages[mid].timestamp <= timestamp {
+                low = mid + 1
+            } else {
+                high = mid
+            }
+        }
+        return low
+    }
+
+    private func reindex(from start: Int) {
+        for index in start..<messages.count {
+            indexByMessageID[messages[index].id] = index
+        }
+    }
+
+    /// Trims oldest messages over the cap; returns the trimmed message IDs.
+    private func trimIfNeeded() -> [String] {
+        guard messages.count > cap else { return [] }
+        let overflow = messages.count - cap
+        let trimmedIDs = messages.prefix(overflow).map(\.id)
+        for id in trimmedIDs {
+            indexByMessageID.removeValue(forKey: id)
+        }
+        messages.removeFirst(overflow)
+        reindex(from: 0)
+        return trimmedIDs
+    }
+}
+
+// MARK: - ConversationChange
+
+/// Typed mutation events for non-UI consumers (delivery tracking,
+/// notifications, sync) that need "something changed in conversation X"
+/// without subscribing to whole message arrays. Emitted on the store's
+/// `changes` subject AFTER the corresponding state is consistent.
+enum ConversationChange {
+    case appended(ConversationID, BitchatMessage)
+    case updated(ConversationID, messageID: String)
+    case statusChanged(ConversationID, messageID: String, DeliveryStatus)
+    case messageRemoved(ConversationID, messageID: String)
+    case cleared(ConversationID)
+    case removed(ConversationID)
+    case migrated(from: ConversationID, to: ConversationID)
+    case unreadChanged(ConversationID, isUnread: Bool)
+}
+
+// MARK: - ConversationStore
+
+/// Sole writer and sole holder of conversation message state. All mutations
+/// go through the intent API below; backing collections are `private(set)`.
+/// Reads are synchronous — writers and readers share the main actor, so
+/// after an intent returns every observer sees the result.
+@MainActor
+final class ConversationStore: ObservableObject {
+    /// Conversation creation order; published so list-style consumers can
+    /// observe conversations appearing/disappearing without rebuilding from
+    /// the dictionary.
+    @Published private(set) var conversationIDs: [ConversationID] = []
+    @Published private(set) var selectedConversationID: ConversationID?
+    @Published private(set) var unreadConversations: Set<ConversationID> = []
+
+    // MARK: Selection state
+    // The two UI selection axes: which public channel is active, and which
+    // private chat (if any) is open on top of it. `selectedConversationID`
+    // is derived: the open private chat wins, otherwise the active public
+    // channel's conversation. Mutate via `setActiveChannel` /
+    // `setSelectedPrivatePeer` only.
+
+    @Published private(set) var activeChannel: ChannelID = .mesh
+    @Published private(set) var selectedPrivatePeerID: PeerID?
+
+    private(set) var conversationsByID: [ConversationID: Conversation] = [:]
+
+    /// Store-level message-ID → conversation-membership map for ID-only
+    /// lookups (delivery receipts arrive with a message ID, not a
+    /// conversation). Maintained incrementally at every mutation point —
+    /// all mutation is centralized in the intent API below, so the map is
+    /// exact, never scanned or rebuilt.
+    ///
+    /// The value is a `Set` because a private message can legitimately live
+    /// in TWO direct conversations: step 2's raw per-peer keying mirrors a
+    /// message into both the stable-key and ephemeral-peer chats
+    /// (`mirrorToEphemeralIfNeeded`). A delivery update must reach both
+    /// copies.
+    private var conversationIDsByMessageID: [String: Set<ConversationID>] = [:]
+
+    /// Monotonic count of messages inserted into any conversation (appends,
+    /// upsert-appends, migration inserts). Field-observability only: the
+    /// periodic store audit folds the delta into its heartbeat line so logs
+    /// carry throughput context. Never read on a hot path.
+    private(set) var appendCount: Int = 0
+
+    /// Sample counter for the mirrored-republish debug log in the ID-only
+    /// `setDeliveryStatus` fan-out (first + every Nth occurrence).
+    private var mirroredRepublishLogCount = 0
+
+    let changes = PassthroughSubject<ConversationChange, Never>()
+
+    // MARK: Intent API
+
+    /// Returns the conversation for `id`, creating it (with the cap policy
+    /// for its kind) on first access.
+    @discardableResult
+    func conversation(for id: ConversationID) -> Conversation {
+        if let existing = conversationsByID[id] {
+            return existing
+        }
+        let conversation = Conversation(id: id, cap: Self.cap(for: id))
+        conversationsByID[id] = conversation
+        conversationIDs.append(id)
+        return conversation
+    }
+
+    /// Appends a message in timestamp order. Returns `false` (and emits
+    /// nothing) if a message with the same ID is already present.
+    @discardableResult
+    func append(_ message: BitchatMessage, to id: ConversationID) -> Bool {
+        let conversation = conversation(for: id)
+        let result = conversation.insert(message)
+        guard result.inserted else { return false }
+        registerMessageID(message.id, in: id)
+        unregisterMessageIDs(result.trimmedMessageIDs, from: id)
+        changes.send(.appended(id, message))
+        return true
+    }
+
+    /// Replace-or-append by message ID (media progress, edits).
+    func upsertByID(_ message: BitchatMessage, in id: ConversationID) {
+        let conversation = conversation(for: id)
+        switch conversation.upsert(message) {
+        case .appended(let trimmedMessageIDs):
+            registerMessageID(message.id, in: id)
+            unregisterMessageIDs(trimmedMessageIDs, from: id)
+            changes.send(.appended(id, message))
+        case .updated:
+            changes.send(.updated(id, messageID: message.id))
+        }
+    }
+
+    /// Applies a delivery status keyed by message ID. Returns `false` when
+    /// the message is unknown or the update would downgrade the status
+    /// (read beats delivered beats sent).
+    @discardableResult
+    func setDeliveryStatus(_ status: DeliveryStatus, forMessageID messageID: String, in id: ConversationID) -> Bool {
+        guard let conversation = conversationsByID[id],
+              conversation.applyDeliveryStatus(status, forMessageID: messageID) else {
+            return false
+        }
+        changes.send(.statusChanged(id, messageID: messageID, status))
+        return true
+    }
+
+    /// Applies a delivery status to EVERY conversation containing
+    /// `messageID` (ID-only — delivery receipts don't know conversations;
+    /// mirrored private copies live in two direct chats). Returns `false`
+    /// when the message is unknown or no copy changed (equal status or
+    /// downgrade — read beats delivered beats sent).
+    ///
+    /// `BitchatMessage` is a reference type, so mirrored copies sharing one
+    /// instance are mutated by the first conversation's apply. The skipped
+    /// conversations still hold the changed message, so they get an explicit
+    /// republish and `.statusChanged` event - otherwise a view observing the
+    /// mirrored conversation would render stale status. Distinct copies whose
+    /// update was genuinely rejected (downgrade) are left untouched, guarded
+    /// by status equality.
+    @discardableResult
+    func setDeliveryStatus(_ status: DeliveryStatus, forMessageID messageID: String) -> Bool {
+        guard let ids = conversationIDsByMessageID[messageID] else { return false }
+        var applied = false
+        var skipped: [ConversationID] = []
+        for id in ids {
+            if setDeliveryStatus(status, forMessageID: messageID, in: id) {
+                applied = true
+            } else {
+                skipped.append(id)
+            }
+        }
+        guard applied else { return false }
+        for id in skipped {
+            guard let conversation = conversationsByID[id],
+                  conversation.message(withID: messageID)?.deliveryStatus == status,
+                  conversation.republishMessage(withID: messageID) else { continue }
+            // Field proof the mirrored-copy republish path actually fires;
+            // sampled (first + every Nth) so mirrored chats can't spam logs.
+            mirroredRepublishLogCount += 1
+            if mirroredRepublishLogCount == 1
+                || mirroredRepublishLogCount.isMultiple(of: TransportConfig.conversationStoreMirroredRepublishLogInterval) {
+                SecureLogger.debug(
+                    "mirrored republish #\(mirroredRepublishLogCount) for \(messageID.prefix(8))… in \(id.auditDescription)",
+                    category: .session
+                )
+            }
+            changes.send(.statusChanged(id, messageID: messageID, status))
+        }
+        return true
+    }
+
+    /// Current delivery status of `messageID` in whichever conversation
+    /// holds it (mirrored copies share status — see `setDeliveryStatus`).
+    func deliveryStatus(forMessageID messageID: String) -> DeliveryStatus? {
+        guard let ids = conversationIDsByMessageID[messageID] else { return nil }
+        for id in ids {
+            if let status = conversationsByID[id]?.message(withID: messageID)?.deliveryStatus {
+                return status
+            }
+        }
+        return nil
+    }
+
+    /// Every conversation currently containing `messageID` (empty when the
+    /// message is unknown).
+    func conversationIDs(forMessageID messageID: String) -> Set<ConversationID> {
+        conversationIDsByMessageID[messageID] ?? []
+    }
+
+    func markRead(_ id: ConversationID) {
+        guard unreadConversations.contains(id) else { return }
+        unreadConversations.remove(id)
+        conversationsByID[id]?.setUnread(false)
+        changes.send(.unreadChanged(id, isUnread: false))
+    }
+
+    func markUnread(_ id: ConversationID) {
+        guard !unreadConversations.contains(id) else { return }
+        let conversation = conversation(for: id)
+        unreadConversations.insert(id)
+        conversation.setUnread(true)
+        changes.send(.unreadChanged(id, isUnread: true))
+    }
+
+    /// Selects a conversation (creating it if needed) or clears the
+    /// selection with `nil`.
+    func select(_ id: ConversationID?) {
+        if let id {
+            conversation(for: id)
+        }
+        guard selectedConversationID != id else { return }
+        selectedConversationID = id
+    }
+
+    /// Switches the active public channel. While no private chat is open
+    /// the selection follows the channel.
+    func setActiveChannel(_ channelID: ChannelID) {
+        if activeChannel != channelID {
+            activeChannel = channelID
+        }
+        refreshDerivedSelection()
+    }
+
+    /// Opens a private chat (`nil` closes it, returning the selection to the
+    /// active public channel's conversation).
+    func setSelectedPrivatePeer(_ peerID: PeerID?) {
+        if selectedPrivatePeerID != peerID {
+            selectedPrivatePeerID = peerID
+        }
+        refreshDerivedSelection()
+    }
+
+    private func refreshDerivedSelection() {
+        if let peerID = selectedPrivatePeerID {
+            select(.directPeer(peerID))
+        } else {
+            select(ConversationID(channelID: activeChannel))
+        }
+    }
+
+    /// Moves all messages from `source` into `destination` (the
+    /// ephemeral↔stable peer-ID handoff): dedups by message ID, preserves
+    /// timestamp order, carries unread state over, and hands off the
+    /// selection — mirroring `ChatPrivateConversationCoordinator`'s
+    /// migration semantics. The source conversation is removed. Emits a
+    /// single `.migrated(from:to:)` once the whole move is consistent.
+    func migrateConversation(from source: ConversationID, to destination: ConversationID) {
+        guard source != destination, let sourceConversation = conversationsByID[source] else { return }
+
+        let destinationConversation = conversation(for: destination)
+        for message in sourceConversation.messages {
+            let result = destinationConversation.insert(message)
+            guard result.inserted else { continue }
+            registerMessageID(message.id, in: destination)
+            unregisterMessageIDs(result.trimmedMessageIDs, from: destination)
+        }
+        for messageID in sourceConversation.messageIDs {
+            unregisterMessageID(messageID, from: source)
+        }
+
+        let wasUnread = unreadConversations.contains(source)
+        let wasSelected = selectedConversationID == source
+
+        conversationsByID.removeValue(forKey: source)
+        conversationIDs.removeAll { $0 == source }
+        unreadConversations.remove(source)
+
+        if wasUnread, !unreadConversations.contains(destination) {
+            unreadConversations.insert(destination)
+            destinationConversation.setUnread(true)
+        }
+        if wasSelected {
+            selectedConversationID = destination
+            // Keep the private-peer selection axis consistent with the
+            // handed-off selection.
+            if let peerID = selectedPrivatePeerID,
+               source == .directPeer(peerID),
+               case .direct(let destinationHandle) = destination {
+                selectedPrivatePeerID = destinationHandle.routingPeerID
+            }
+        }
+
+        changes.send(.migrated(from: source, to: destination))
+    }
+
+    /// Removes a single message by ID from a conversation. Returns the
+    /// removed message, or `nil` (emitting nothing) when the conversation or
+    /// message is unknown.
+    @discardableResult
+    func removeMessage(withID messageID: String, from id: ConversationID) -> BitchatMessage? {
+        guard let conversation = conversationsByID[id],
+              let removed = conversation.remove(messageID: messageID) else {
+            return nil
+        }
+        unregisterMessageID(messageID, from: id)
+        changes.send(.messageRemoved(id, messageID: messageID))
+        return removed
+    }
+
+    /// Removes every message matching `predicate` from a conversation,
+    /// emitting one `.messageRemoved` per removed message after the
+    /// conversation is consistent. No-op for unknown conversations.
+    func removeMessages(from id: ConversationID, where predicate: (BitchatMessage) -> Bool) {
+        guard let conversation = conversationsByID[id] else { return }
+        let removedIDs = conversation.removeAll(where: predicate)
+        unregisterMessageIDs(removedIDs, from: id)
+        for messageID in removedIDs {
+            changes.send(.messageRemoved(id, messageID: messageID))
+        }
+    }
+
+    /// Empties a conversation's timeline but keeps the conversation (and
+    /// its unread/selection state) alive.
+    func clear(_ id: ConversationID) {
+        guard let conversation = conversationsByID[id] else { return }
+        for messageID in conversation.messageIDs {
+            unregisterMessageID(messageID, from: id)
+        }
+        conversation.clearMessages()
+        changes.send(.cleared(id))
+    }
+
+    /// Removes a conversation entirely, including unread state; clears the
+    /// selection if it pointed at the removed conversation.
+    func removeConversation(_ id: ConversationID) {
+        guard let conversation = conversationsByID.removeValue(forKey: id) else { return }
+        for messageID in conversation.messageIDs {
+            unregisterMessageID(messageID, from: id)
+        }
+        conversationIDs.removeAll { $0 == id }
+        unreadConversations.remove(id)
+        if selectedConversationID == id {
+            selectedConversationID = nil
+        }
+        changes.send(.removed(id))
+    }
+
+    func clearAll() {
+        let removedIDs = conversationIDs
+        guard !removedIDs.isEmpty || selectedConversationID != nil else { return }
+
+        conversationsByID.removeAll()
+        conversationIDs.removeAll()
+        unreadConversations.removeAll()
+        conversationIDsByMessageID.removeAll()
+        if selectedConversationID != nil {
+            selectedConversationID = nil
+        }
+
+        for id in removedIDs {
+            changes.send(.removed(id))
+        }
+    }
+
+    // MARK: Diagnostics
+
+    /// Total messages across all conversations. O(#conversations) — heartbeat
+    /// logging only, never a hot path.
+    var totalMessageCount: Int {
+        conversationsByID.values.reduce(0) { $0 + $1.messages.count }
+    }
+
+    /// Number of distinct message IDs in the store-level membership map.
+    var messageIDMapCount: Int {
+        conversationIDsByMessageID.count
+    }
+
+    /// Verifies the store's correctness invariants and returns human-readable
+    /// violations (empty = healthy). Intended for a periodic field audit:
+    /// O(total messages) and allocation-free while healthy. Checks:
+    /// - the `conversationIDs` ordering array matches `conversationsByID`
+    /// - per conversation: ID index exact, cap held, timestamp order
+    ///   (see `Conversation.collectInvariantViolations`)
+    /// - the message-ID → conversation map matches reality exactly: every
+    ///   mapped membership points at a live conversation actually holding
+    ///   the message, and total memberships equal total messages (with the
+    ///   forward check, equality proves no conversation message is missing
+    ///   from the map)
+    /// - `unreadConversations` only references existing conversations
+    /// - `selectedConversationID`, when set, references an existing
+    ///   conversation (`select(_:)` creates on selection and
+    ///   `removeConversation`/`clearAll` clear it, so existence is the
+    ///   invariant for both the channel-derived and direct-peer cases)
+    func auditInvariants() -> [String] {
+        var violations: [String] = []
+
+        if conversationIDs.count != conversationsByID.count {
+            violations.append("conversationIDs lists \(conversationIDs.count) conversations but dictionary holds \(conversationsByID.count)")
+        }
+        for id in conversationIDs where conversationsByID[id] == nil {
+            violations.append("conversationIDs lists \(id.auditDescription) but no conversation exists")
+        }
+
+        var totalMessages = 0
+        for (id, conversation) in conversationsByID {
+            totalMessages += conversation.messages.count
+            conversation.collectInvariantViolations(into: &violations, label: id.auditDescription)
+        }
+
+        var totalMappedMemberships = 0
+        for (messageID, ids) in conversationIDsByMessageID {
+            totalMappedMemberships += ids.count
+            if ids.isEmpty {
+                violations.append("message map: \(messageID.prefix(8))… has an empty membership set")
+            }
+            for id in ids {
+                guard let conversation = conversationsByID[id] else {
+                    violations.append("message map: \(messageID.prefix(8))… claims unknown conversation \(id.auditDescription)")
+                    continue
+                }
+                if !conversation.containsMessage(withID: messageID) {
+                    violations.append("message map: \(messageID.prefix(8))… not present in claimed conversation \(id.auditDescription)")
+                }
+            }
+        }
+        if totalMappedMemberships != totalMessages {
+            violations.append("message map holds \(totalMappedMemberships) memberships but conversations hold \(totalMessages) messages")
+        }
+
+        for id in unreadConversations where conversationsByID[id] == nil {
+            violations.append("unreadConversations contains unknown conversation \(id.auditDescription)")
+        }
+
+        if let selected = selectedConversationID, conversationsByID[selected] == nil {
+            violations.append("selectedConversationID \(selected.auditDescription) has no conversation")
+        }
+
+        return violations
+    }
+
+    // MARK: Internals
+
+    private func registerMessageID(_ messageID: String, in id: ConversationID) {
+        conversationIDsByMessageID[messageID, default: []].insert(id)
+        // Single choke point for every successful insertion (append, upsert
+        // append, migration insert) — the audit heartbeat's throughput delta.
+        appendCount += 1
+    }
+
+    private func unregisterMessageID(_ messageID: String, from id: ConversationID) {
+        guard var ids = conversationIDsByMessageID[messageID] else { return }
+        ids.remove(id)
+        if ids.isEmpty {
+            conversationIDsByMessageID.removeValue(forKey: messageID)
+        } else {
+            conversationIDsByMessageID[messageID] = ids
+        }
+    }
+
+    private func unregisterMessageIDs(_ messageIDs: [String], from id: ConversationID) {
+        for messageID in messageIDs {
+            unregisterMessageID(messageID, from: id)
+        }
+    }
+
+    private static func cap(for id: ConversationID) -> Int {
+        switch id {
+        case .mesh:
+            return TransportConfig.meshTimelineCap
+        case .geohash:
+            return TransportConfig.geoTimelineCap
+        case .direct:
+            return TransportConfig.privateChatCap
+        }
+    }
+}
+
+// MARK: - Direct-conversation keying + derived views
+
+extension ConversationID {
+    /// Direct-conversation ID keyed by the *raw* routing peer ID.
+    ///
+    /// Direct conversations are deliberately keyed per `PeerID`, not per
+    /// resolved identity: the private-chat coordinators mirror messages into
+    /// both the ephemeral and stable peer's conversations
+    /// (`mirrorToEphemeralIfNeeded`) and consolidate/migrate between them
+    /// explicitly, so a raw lookup by whichever peer ID is selected always
+    /// finds the right timeline without an identity-resolution layer.
+    static func directPeer(_ peerID: PeerID) -> ConversationID {
+        .direct(PeerHandle(id: "peer:\(peerID.id)", routingPeerID: peerID))
+    }
+}
+
+extension ConversationStore {
+    /// All direct conversations' messages keyed by routing peer ID — the
+    /// shape `ChatViewModel.privateChats` exposes to the coordinators.
+    /// Values are the conversations' backing arrays (COW), so building this
+    /// is O(#conversations), not O(#messages).
+    func directMessagesByRoutingPeerID() -> [PeerID: [BitchatMessage]] {
+        var messagesByPeerID: [PeerID: [BitchatMessage]] = [:]
+        messagesByPeerID.reserveCapacity(conversationsByID.count)
+        for (id, conversation) in conversationsByID {
+            guard case .direct(let handle) = id else { continue }
+            messagesByPeerID[handle.routingPeerID] = conversation.messages
+        }
+        return messagesByPeerID
+    }
+
+    /// Unread direct conversations as routing peer IDs — the shape
+    /// `ChatViewModel.unreadPrivateMessages` exposes to the coordinators.
+    func unreadDirectRoutingPeerIDs() -> Set<PeerID> {
+        var peerIDs = Set<PeerID>()
+        for id in unreadConversations {
+            guard case .direct(let handle) = id else { continue }
+            peerIDs.insert(handle.routingPeerID)
+        }
+        return peerIDs
+    }
+
+    /// `true` when any direct conversation contains a message with `messageID`
+    /// (O(1) via the store-level message-ID → conversation map).
+    func directConversationsContainMessage(withID messageID: String) -> Bool {
+        conversationIDs(forMessageID: messageID).contains { id in
+            if case .direct = id { return true }
+            return false
+        }
+    }
+
+    /// Message IDs across all direct conversations (read-receipt pruning
+    /// keeps only receipts whose messages still exist).
+    func directMessageIDs() -> Set<String> {
+        var messageIDs = Set<String>()
+        for (id, conversation) in conversationsByID {
+            guard case .direct = id else { continue }
+            messageIDs.formUnion(conversation.messageIDs)
+        }
+        return messageIDs
+    }
+
+    /// Removes every direct conversation (panic clear).
+    func removeAllDirectConversations() {
+        let directIDs = conversationIDs.filter { id in
+            if case .direct = id { return true }
+            return false
+        }
+        for id in directIDs {
+            removeConversation(id)
+        }
+    }
+}
+
+// MARK: - Diagnostics support
+
+extension ConversationID {
+    /// Short, log-safe description for audit/diagnostic lines. Direct
+    /// conversations truncate the handle so full peer keys never hit logs.
+    fileprivate var auditDescription: String {
+        switch self {
+        case .mesh:
+            return "mesh"
+        case .geohash(let geohash):
+            return "geo:\(geohash)"
+        case .direct(let handle):
+            return "direct:\(handle.id.prefix(13))…"
+        }
+    }
+}
+
+#if DEBUG
+// Test-only corruption hooks for `auditInvariants()` tests. The store is the
+// sole writer by design — `Conversation`'s mutators are fileprivate and the
+// store's backing collections are private — so the inconsistent states the
+// audit exists to catch CANNOT be manufactured through the intent API. These
+// DEBUG-only hooks deliberately bypass that lockdown to inject exactly those
+// impossible states. Never call them outside tests.
+extension Conversation {
+    /// Points an existing message's index entry at the wrong position
+    /// (positions 0 and 1 swap their index entries). Requires >= 2 messages.
+    func _testCorruptIndexEntries() {
+        guard messages.count >= 2 else { return }
+        indexByMessageID[messages[0].id] = 1
+        indexByMessageID[messages[1].id] = 0
+    }
+
+    /// Drops a message's index entry entirely (count mismatch + missing).
+    func _testRemoveIndexEntry(forMessageID messageID: String) {
+        indexByMessageID.removeValue(forKey: messageID)
+    }
+
+    /// Swaps the first and last messages while keeping the index consistent,
+    /// so ONLY the timestamp-order invariant is violated (requires the two
+    /// messages to have distinct timestamps).
+    func _testCorruptOrderingPreservingIndex() {
+        guard messages.count >= 2 else { return }
+        messages.swapAt(0, messages.count - 1)
+        indexByMessageID[messages[0].id] = 0
+        indexByMessageID[messages[messages.count - 1].id] = messages.count - 1
+    }
+}
+
+extension ConversationStore {
+    /// Adds a map membership that the conversation does not actually hold.
+    func _testRegisterPhantomMessageID(_ messageID: String, in id: ConversationID) {
+        conversationIDsByMessageID[messageID, default: []].insert(id)
+    }
+
+    /// Drops a real map membership (conversation message missing from map).
+    func _testUnregisterMessageID(_ messageID: String, from id: ConversationID) {
+        conversationIDsByMessageID[messageID]?.remove(id)
+        if conversationIDsByMessageID[messageID]?.isEmpty == true {
+            conversationIDsByMessageID.removeValue(forKey: messageID)
+        }
+    }
+
+    /// Appends past the conversation cap, bypassing trim (map kept exact so
+    /// only the cap invariant is violated).
+    func _testAppendBypassingCap(_ message: BitchatMessage, to id: ConversationID) {
+        let conversation = conversation(for: id)
+        conversation._testAppendBypassingTrim(message)
+        conversationIDsByMessageID[message.id, default: []].insert(id)
+    }
+
+    /// Marks a nonexistent conversation unread without creating it.
+    func _testInsertUnreadConversationID(_ id: ConversationID) {
+        unreadConversations.insert(id)
+    }
+
+    /// Sets the selection directly, without `select(_:)`'s create-on-select.
+    func _testSetSelectedConversationID(_ id: ConversationID?) {
+        selectedConversationID = id
+    }
+}
+
+extension Conversation {
+    fileprivate func _testAppendBypassingTrim(_ message: BitchatMessage) {
+        messages.append(message)
+        indexByMessageID[message.id] = messages.count - 1
+    }
+}
+#endif
+
+// MARK: - Public timeline derived views
+
+extension ConversationStore {
+    /// Removes a message by ID from whichever public (mesh/geohash)
+    /// conversation contains it. Returns the removed message, if any.
+    @discardableResult
+    func removePublicMessage(withID messageID: String) -> BitchatMessage? {
+        for id in conversationIDs(forMessageID: messageID) {
+            switch id {
+            case .mesh, .geohash:
+                return removeMessage(withID: messageID, from: id)
+            case .direct:
+                continue
+            }
+        }
+        return nil
+    }
+}

bitchat/App/ConversationUIModel.swift

@@ -0,0 +1,209 @@
+import BitFoundation
+import Combine
+import SwiftUI
+#if os(iOS)
+import UIKit
+#endif
+
+@MainActor
+final class ConversationUIModel: ObservableObject {
+    @Published private(set) var showAutocomplete = false
+    @Published private(set) var autocompleteSuggestions: [String] = []
+    @Published private(set) var currentNickname: String
+    @Published private(set) var isBatchingPublic = false
+    @Published private(set) var canSendMediaInCurrentContext = true
+
+    private let chatViewModel: ChatViewModel
+    private let privateConversationModel: PrivateConversationModel
+    private let conversations: ConversationStore
+    private var activeChannel: ChannelID
+    private var cancellables = Set<AnyCancellable>()
+
+    init(
+        chatViewModel: ChatViewModel,
+        privateConversationModel: PrivateConversationModel,
+        conversations: ConversationStore
+    ) {
+        self.chatViewModel = chatViewModel
+        self.privateConversationModel = privateConversationModel
+        self.conversations = conversations
+        self.activeChannel = conversations.activeChannel
+        self.currentNickname = chatViewModel.nickname
+        self.isBatchingPublic = chatViewModel.isBatchingPublic
+        self.showAutocomplete = chatViewModel.showAutocomplete
+        self.autocompleteSuggestions = chatViewModel.autocompleteSuggestions
+        self.canSendMediaInCurrentContext = chatViewModel.canSendMediaInCurrentContext
+
+        bind()
+    }
+
+    func setCurrentColorScheme(_ colorScheme: ColorScheme) {
+        chatViewModel.currentColorScheme = colorScheme
+    }
+
+    func setCurrentTheme(_ theme: AppTheme) {
+        chatViewModel.currentTheme = theme
+    }
+
+    func sendMessage(_ message: String) {
+        chatViewModel.sendMessage(message)
+    }
+
+    /// Resends a failed private message through the normal send path,
+    /// removing the failed original so the re-submission replaces it
+    /// instead of stacking a duplicate under the red bubble.
+    func resendFailedPrivateMessage(_ message: BitchatMessage) {
+        chatViewModel.removePrivateMessage(withID: message.id)
+        chatViewModel.sendMessage(message.content)
+    }
+
+    func clearCurrentConversation() {
+        chatViewModel.sendMessage("/clear")
+    }
+
+    func sendHug(to sender: String) {
+        chatViewModel.sendMessage("/hug @\(sender)")
+    }
+
+    func sendSlap(to sender: String) {
+        chatViewModel.sendMessage("/slap @\(sender)")
+    }
+
+    func block(peerID: PeerID?, displayName: String?) {
+        guard let displayName else { return }
+
+        if let peerID, peerID.isGeoChat,
+           let full = chatViewModel.fullNostrHex(forSenderPeerID: peerID) {
+            chatViewModel.blockGeohashUser(pubkeyHexLowercased: full, displayName: displayName)
+        } else if let peerID, !peerID.isGeoDM, !peerID.isGeoChat {
+            // Mesh: block the peer's stable Noise identity resolved from the
+            // tapped peerID rather than re-resolving a display-name string.
+            chatViewModel.blockMeshPeer(peerID: peerID, displayName: displayName)
+        } else {
+            chatViewModel.sendMessage("/block \(displayName)")
+        }
+    }
+
+    /// Mesh counterpart of `block(peerID:displayName:)`. Resolves the unblock by
+    /// the tapped peer's stable identity so the exact row is unblocked — this
+    /// also works for offline peers, which the `/unblock <displayName>` command
+    /// cannot resolve.
+    func unblock(peerID: PeerID, displayName: String) {
+        chatViewModel.unblockMeshPeer(peerID: peerID, displayName: displayName)
+    }
+
+    func updateAutocomplete(for text: String, cursorPosition: Int) {
+        chatViewModel.updateAutocomplete(for: text, cursorPosition: cursorPosition)
+    }
+
+    func completeNickname(_ nickname: String, in text: inout String) -> Int {
+        chatViewModel.completeNickname(nickname, in: &text)
+    }
+
+    func formatMessage(_ message: BitchatMessage, colorScheme: ColorScheme, theme: AppTheme? = nil) -> AttributedString {
+        chatViewModel.formatMessageAsText(message, colorScheme: colorScheme, theme: theme)
+    }
+
+    func formatMessageHeader(_ message: BitchatMessage, colorScheme: ColorScheme, theme: AppTheme? = nil) -> AttributedString {
+        chatViewModel.formatMessageHeader(message, colorScheme: colorScheme, theme: theme)
+    }
+
+    func mediaAttachment(for message: BitchatMessage) -> BitchatMessage.Media? {
+        message.mediaAttachment(for: currentNickname)
+    }
+
+    func isSelfSender(peerID: PeerID?, displayName: String?) -> Bool {
+        chatViewModel.isSelfSender(peerID: peerID, displayName: displayName)
+    }
+
+    func isSentByCurrentUser(_ message: BitchatMessage) -> Bool {
+        message.sender == currentNickname || message.sender.hasPrefix(currentNickname + "#")
+    }
+
+    func isMediaMessageFromCurrentUser(_ message: BitchatMessage) -> Bool {
+        message.sender == currentNickname || message.senderPeerID == chatViewModel.meshService.myPeerID
+    }
+
+    func senderDisplayName(for peerID: PeerID, fallbackMessages: [BitchatMessage]) -> String? {
+        if peerID.isGeoDM || peerID.isGeoChat {
+            return chatViewModel.geohashDisplayName(for: peerID)
+        }
+        if let nickname = chatViewModel.meshService.peerNickname(peerID: peerID) {
+            return nickname
+        }
+        return fallbackMessages.last(where: { $0.senderPeerID == peerID && $0.sender != "system" })?.sender
+    }
+
+    #if os(iOS)
+    func processSelectedImage(_ image: UIImage?) {
+        chatViewModel.processThenSendImage(image)
+    }
+    #endif
+
+    func processSelectedImage(from url: URL?) {
+        #if os(macOS)
+        chatViewModel.processThenSendImage(from: url)
+        #endif
+    }
+
+    func sendVoiceNote(at url: URL) {
+        chatViewModel.sendVoiceNote(at: url)
+    }
+
+    func cancelMediaSend(messageID: String) {
+        chatViewModel.cancelMediaSend(messageID: messageID)
+    }
+
+    func deleteMediaMessage(messageID: String) {
+        chatViewModel.deleteMediaMessage(messageID: messageID)
+    }
+
+    private func bind() {
+        chatViewModel.$nickname
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$currentNickname)
+
+        chatViewModel.$showAutocomplete
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$showAutocomplete)
+
+        chatViewModel.$autocompleteSuggestions
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$autocompleteSuggestions)
+
+        chatViewModel.$isBatchingPublic
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$isBatchingPublic)
+
+        conversations.$activeChannel
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] channel in
+                self?.activeChannel = channel
+                self?.refreshComputedState()
+            }
+            .store(in: &cancellables)
+
+        privateConversationModel.$selectedPeerID
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refreshComputedState()
+            }
+            .store(in: &cancellables)
+    }
+
+    private func refreshComputedState() {
+        if let selectedPeerID = privateConversationModel.selectedPeerID {
+            // Media transfer is not wired for groups in v1; keep it off so the
+            // composer can't strand a media placeholder that never sends.
+            canSendMediaInCurrentContext = !(selectedPeerID.isGeoDM || selectedPeerID.isGeoChat || selectedPeerID.isGroup)
+            return
+        }
+
+        switch activeChannel {
+        case .mesh:
+            canSendMediaInCurrentContext = true
+        case .location:
+            canSendMediaInCurrentContext = false
+        }
+    }
+}

bitchat/App/LocationChannelsModel.swift

@@ -0,0 +1,190 @@
+import BitFoundation
+import Combine
+import Foundation
+
+@MainActor
+final class LocationChannelsModel: ObservableObject {
+    @Published private(set) var permissionState: LocationChannelManager.PermissionState
+    @Published private(set) var availableChannels: [GeohashChannel]
+    @Published private(set) var selectedChannel: ChannelID
+    @Published private(set) var teleported: Bool
+    @Published private(set) var bookmarks: [String]
+    @Published private(set) var bookmarkNames: [String: String]
+    @Published private(set) var locationNames: [GeohashChannelLevel: String]
+    @Published private(set) var userTorEnabled: Bool
+    @Published private(set) var gatewayEnabled: Bool
+
+    private let manager: LocationChannelManager
+    private let network: NetworkActivationService
+    private let gateway: GatewayService
+    private var cancellables = Set<AnyCancellable>()
+
+    init(
+        manager: LocationChannelManager? = nil,
+        network: NetworkActivationService? = nil,
+        gateway: GatewayService? = nil
+    ) {
+        let manager = manager ?? .shared
+        let network = network ?? .shared
+        let gateway = gateway ?? .shared
+
+        self.manager = manager
+        self.network = network
+        self.gateway = gateway
+        self.gatewayEnabled = gateway.isEnabled
+        self.permissionState = manager.permissionState
+        self.availableChannels = manager.availableChannels
+        self.selectedChannel = manager.selectedChannel
+        self.teleported = manager.teleported
+        self.bookmarks = manager.bookmarks
+        self.bookmarkNames = manager.bookmarkNames
+        self.locationNames = manager.locationNames
+        self.userTorEnabled = network.userTorEnabled
+
+        bind()
+    }
+
+    var currentBuildingGeohash: String? {
+        availableChannels.first(where: { $0.level == .building })?.geohash
+    }
+
+    func isSelected(_ channel: GeohashChannel) -> Bool {
+        guard case .location(let selected) = selectedChannel else { return false }
+        return selected == channel
+    }
+
+    func isBookmarked(_ geohash: String) -> Bool {
+        manager.isBookmarked(geohash)
+    }
+
+    func enableLocationChannels() {
+        manager.enableLocationChannels()
+    }
+
+    func refreshChannels() {
+        manager.refreshChannels()
+    }
+
+    func enableAndRefresh() {
+        manager.enableLocationChannels()
+        manager.refreshChannels()
+    }
+
+    func beginLiveRefresh() {
+        manager.beginLiveRefresh()
+    }
+
+    func endLiveRefresh() {
+        manager.endLiveRefresh()
+    }
+
+    func select(_ channel: ChannelID) {
+        manager.select(channel)
+    }
+
+    func markTeleported(for geohash: String, _ flag: Bool) {
+        manager.markTeleported(for: geohash, flag)
+    }
+
+    func toggleBookmark(_ geohash: String) {
+        manager.toggleBookmark(geohash)
+    }
+
+    func resolveBookmarkNameIfNeeded(for geohash: String) {
+        manager.resolveBookmarkNameIfNeeded(for: geohash)
+    }
+
+    func locationName(for level: GeohashChannelLevel) -> String? {
+        locationNames[level]
+    }
+
+    func setUserTorEnabled(_ enabled: Bool) {
+        network.setUserTorEnabled(enabled)
+    }
+
+    func setGatewayEnabled(_ enabled: Bool) {
+        gateway.setEnabled(enabled)
+    }
+
+    func refreshMeshChannelsIfNeeded() {
+        guard case .mesh = selectedChannel,
+              permissionState == .authorized,
+              availableChannels.isEmpty else {
+            return
+        }
+        refreshChannels()
+    }
+
+    func openLocationChannel(for geohash: String) {
+        let normalized = geohash.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
+        let allowed = Set("0123456789bcdefghjkmnpqrstuvwxyz")
+        guard (2...12).contains(normalized.count),
+              normalized.allSatisfy({ allowed.contains($0) }) else {
+            return
+        }
+
+        let channel = GeohashChannel(level: level(forLength: normalized.count), geohash: normalized)
+        let isRegional = availableChannels.contains { $0.geohash == normalized }
+        if !isRegional && !availableChannels.isEmpty {
+            markTeleported(for: normalized, true)
+        }
+        select(.location(channel))
+    }
+
+    func teleport(to geohash: String) {
+        let normalized = geohash.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
+        let channel = GeohashChannel(level: level(forLength: normalized.count), geohash: normalized)
+        markTeleported(for: normalized, true)
+        select(.location(channel))
+    }
+
+    private func bind() {
+        manager.$permissionState
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$permissionState)
+
+        manager.$availableChannels
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$availableChannels)
+
+        manager.$selectedChannel
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$selectedChannel)
+
+        manager.$teleported
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$teleported)
+
+        manager.$bookmarks
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$bookmarks)
+
+        manager.$bookmarkNames
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$bookmarkNames)
+
+        manager.$locationNames
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$locationNames)
+
+        network.$userTorEnabled
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$userTorEnabled)
+
+        gateway.$isEnabled
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$gatewayEnabled)
+    }
+
+    private func level(forLength length: Int) -> GeohashChannelLevel {
+        switch length {
+        case 0...2: return .region
+        case 3...4: return .province
+        case 5: return .city
+        case 6: return .neighborhood
+        case 7: return .block
+        case 8...12: return .building
+        default: return .block
+        }
+    }
+}

bitchat/App/LocationPresenceStore.swift

@@ -0,0 +1,51 @@
+import Combine
+import Foundation
+
+@MainActor
+final class LocationPresenceStore: ObservableObject {
+    @Published private(set) var currentGeohash: String?
+    @Published private(set) var geoNicknames: [String: String] = [:]
+    @Published private(set) var teleportedGeo: Set<String> = []
+
+    func setCurrentGeohash(_ geohash: String?) {
+        currentGeohash = geohash?.lowercased()
+    }
+
+    func setNickname(_ nickname: String, for pubkeyHex: String) {
+        geoNicknames[pubkeyHex.lowercased()] = nickname
+    }
+
+    func replaceGeoNicknames(_ nicknames: [String: String]) {
+        geoNicknames = Dictionary(
+            uniqueKeysWithValues: nicknames.map { key, value in
+                (key.lowercased(), value)
+            }
+        )
+    }
+
+    func clearGeoNicknames() {
+        geoNicknames.removeAll()
+    }
+
+    func markTeleported(_ pubkeyHex: String) {
+        teleportedGeo.insert(pubkeyHex.lowercased())
+    }
+
+    func clearTeleported(_ pubkeyHex: String) {
+        teleportedGeo.remove(pubkeyHex.lowercased())
+    }
+
+    func replaceTeleportedGeo(_ pubkeys: Set<String>) {
+        teleportedGeo = Set(pubkeys.map { $0.lowercased() })
+    }
+
+    func clearTeleportedGeo() {
+        teleportedGeo.removeAll()
+    }
+
+    func reset() {
+        currentGeohash = nil
+        geoNicknames.removeAll()
+        teleportedGeo.removeAll()
+    }
+}

bitchat/App/PeerIdentityStore.swift

@@ -0,0 +1,125 @@
+import BitFoundation
+import Combine
+import Foundation
+
+@MainActor
+final class PeerIdentityStore: ObservableObject {
+    @Published private(set) var encryptionStatuses: [PeerID: EncryptionStatus] = [:]
+    @Published private(set) var verifiedFingerprints: Set<String> = []
+
+    private(set) var peerFingerprintsByPeerID: [PeerID: String] = [:]
+    private(set) var selectedPrivateChatFingerprint: String?
+
+    private var stablePeerIDsByShortID: [PeerID: PeerID] = [:]
+    private var encryptionStatusCache: [PeerID: EncryptionStatus] = [:]
+
+    func stablePeerID(forShortID peerID: PeerID) -> PeerID? {
+        stablePeerIDsByShortID[peerID]
+    }
+
+    func shortPeerID(forStablePeerID stablePeerID: PeerID) -> PeerID? {
+        stablePeerIDsByShortID.first(where: { $0.value == stablePeerID })?.key
+    }
+
+    func setStablePeerID(_ stablePeerID: PeerID, forShortID peerID: PeerID) {
+        stablePeerIDsByShortID[peerID] = stablePeerID
+    }
+
+    func replaceStablePeerIDs(_ mappings: [PeerID: PeerID]) {
+        stablePeerIDsByShortID = mappings
+    }
+
+    func fingerprint(for peerID: PeerID) -> String? {
+        peerFingerprintsByPeerID[peerID]
+    }
+
+    func setFingerprint(_ fingerprint: String?, for peerID: PeerID) {
+        if let fingerprint {
+            peerFingerprintsByPeerID[peerID] = fingerprint
+        } else {
+            peerFingerprintsByPeerID.removeValue(forKey: peerID)
+        }
+    }
+
+    func replaceFingerprintMappings(_ mappings: [PeerID: String]) {
+        peerFingerprintsByPeerID = mappings
+    }
+
+    @discardableResult
+    func migrateFingerprintMapping(
+        from oldPeerID: PeerID,
+        to newPeerID: PeerID,
+        fallback: String? = nil
+    ) -> String? {
+        let fingerprint = peerFingerprintsByPeerID.removeValue(forKey: oldPeerID) ?? fallback
+        if let fingerprint {
+            peerFingerprintsByPeerID[newPeerID] = fingerprint
+            if selectedPrivateChatFingerprint == nil {
+                selectedPrivateChatFingerprint = fingerprint
+            }
+        }
+        return fingerprint
+    }
+
+    func setSelectedPrivateChatFingerprint(_ fingerprint: String?) {
+        selectedPrivateChatFingerprint = fingerprint
+    }
+
+    func cachedEncryptionStatus(for peerID: PeerID) -> EncryptionStatus? {
+        encryptionStatusCache[peerID]
+    }
+
+    func setCachedEncryptionStatus(_ status: EncryptionStatus, for peerID: PeerID) {
+        encryptionStatusCache[peerID] = status
+    }
+
+    func invalidateEncryptionCache(for peerID: PeerID? = nil) {
+        if let peerID {
+            encryptionStatusCache.removeValue(forKey: peerID)
+        } else {
+            encryptionStatusCache.removeAll()
+        }
+    }
+
+    func encryptionStatus(for peerID: PeerID) -> EncryptionStatus? {
+        encryptionStatuses[peerID]
+    }
+
+    func setEncryptionStatus(_ status: EncryptionStatus?, for peerID: PeerID) {
+        if let status {
+            encryptionStatuses[peerID] = status
+        } else {
+            encryptionStatuses.removeValue(forKey: peerID)
+        }
+        invalidateEncryptionCache(for: peerID)
+    }
+
+    func replaceEncryptionStatuses(_ statuses: [PeerID: EncryptionStatus]) {
+        encryptionStatuses = statuses
+    }
+
+    func setVerifiedFingerprints(_ fingerprints: Set<String>) {
+        verifiedFingerprints = fingerprints
+    }
+
+    func setVerified(_ fingerprint: String, verified: Bool) {
+        if verified {
+            verifiedFingerprints.insert(fingerprint)
+        } else {
+            verifiedFingerprints.remove(fingerprint)
+        }
+    }
+
+    func isVerified(_ fingerprint: String) -> Bool {
+        verifiedFingerprints.contains(fingerprint)
+    }
+
+    func clearAll() {
+        encryptionStatuses.removeAll()
+        verifiedFingerprints.removeAll()
+        peerFingerprintsByPeerID.removeAll()
+        selectedPrivateChatFingerprint = nil
+        stablePeerIDsByShortID.removeAll()
+        encryptionStatusCache.removeAll()
+    }
+}

bitchat/App/PeerListModel.swift

@@ -0,0 +1,299 @@
+import BitFoundation
+import Combine
+import SwiftUI
+
+struct MeshPeerRow: Identifiable, Equatable {
+    let peerID: PeerID
+    let displayName: String
+    let isMe: Bool
+    let hasUnread: Bool
+    let isBlocked: Bool
+    let isFavorite: Bool
+    let isConnected: Bool
+    let isReachable: Bool
+    let isMutualFavorite: Bool
+    let encryptionStatus: EncryptionStatus
+    let showsVerifiedBadgeWhenOffline: Bool
+    /// Vouched-for by someone I verified, without an explicit verification of
+    /// mine — rendered as the unfilled seal (verified gets the filled one).
+    let showsVouchedBadge: Bool
+
+    var id: String { peerID.id }
+}
+
+struct GeohashPersonRow: Identifiable, Equatable {
+    let id: String
+    let displayName: String
+    let isMe: Bool
+    let isTeleported: Bool
+    let isBlocked: Bool
+}
+
+struct GroupChatRow: Identifiable, Equatable {
+    let peerID: PeerID
+    let name: String
+    let memberCount: Int
+    let isCreator: Bool
+    let hasUnread: Bool
+
+    var id: String { peerID.id }
+}
+
+@MainActor
+final class PeerListModel: ObservableObject {
+    @Published private(set) var allPeers: [BitchatPeer] = []
+    @Published private(set) var meshRows: [MeshPeerRow] = []
+    @Published private(set) var geohashPeople: [GeohashPersonRow] = []
+    @Published private(set) var groupRows: [GroupChatRow] = []
+    @Published private(set) var reachableMeshPeerCount = 0
+    @Published private(set) var connectedMeshPeerCount = 0
+    @Published private(set) var visibleGeohashPeerCount = 0
+    @Published private(set) var renderID = ""
+
+    private let chatViewModel: ChatViewModel
+    private let conversations: ConversationStore
+    private let locationChannelsModel: LocationChannelsModel
+    private let peerIdentityStore: PeerIdentityStore
+    private let locationPresenceStore: LocationPresenceStore
+    private var cancellables = Set<AnyCancellable>()
+
+    init(
+        chatViewModel: ChatViewModel,
+        conversations: ConversationStore,
+        locationChannelsModel: LocationChannelsModel? = nil,
+        peerIdentityStore: PeerIdentityStore? = nil,
+        locationPresenceStore: LocationPresenceStore? = nil
+    ) {
+        self.chatViewModel = chatViewModel
+        self.conversations = conversations
+        self.locationChannelsModel = locationChannelsModel ?? LocationChannelsModel()
+        self.peerIdentityStore = peerIdentityStore ?? chatViewModel.peerIdentityStore
+        self.locationPresenceStore = locationPresenceStore ?? chatViewModel.locationPresenceStore
+        self.allPeers = chatViewModel.allPeers
+
+        bind()
+        refresh()
+    }
+
+    func colorForMeshPeer(id peerID: PeerID, isDark: Bool) -> Color {
+        chatViewModel.colorForMeshPeer(id: peerID, isDark: isDark)
+    }
+
+    func colorForGeohashPerson(id: String, isDark: Bool) -> Color {
+        chatViewModel.colorForNostrPubkey(id, isDark: isDark)
+    }
+
+    func participantCount(for geohash: String) -> Int {
+        chatViewModel.geohashParticipantCount(for: geohash)
+    }
+
+    func startConversation(with peerID: PeerID) {
+        chatViewModel.startPrivateChat(with: peerID)
+    }
+
+    func toggleFavorite(peerID: PeerID) {
+        chatViewModel.toggleFavorite(peerID: peerID)
+    }
+
+    func openGeohashDirectMessage(with pubkeyHex: String) {
+        chatViewModel.startGeohashDM(withPubkeyHex: pubkeyHex)
+    }
+
+    func blockGeohashUser(pubkeyHexLowercased: String, displayName: String) {
+        chatViewModel.blockGeohashUser(
+            pubkeyHexLowercased: pubkeyHexLowercased,
+            displayName: displayName
+        )
+    }
+
+    func unblockGeohashUser(pubkeyHexLowercased: String, displayName: String) {
+        chatViewModel.unblockGeohashUser(
+            pubkeyHexLowercased: pubkeyHexLowercased,
+            displayName: displayName
+        )
+    }
+
+    private func bind() {
+        chatViewModel.$allPeers
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] peers in
+                self?.allPeers = peers
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+
+        chatViewModel.$nickname
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+
+        locationPresenceStore.$teleportedGeo
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+
+        conversations.$unreadConversations
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+
+        chatViewModel.groupStore.$groups
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+
+        peerIdentityStore.$encryptionStatuses
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+
+        peerIdentityStore.$verifiedFingerprints
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+
+        NotificationCenter.default.publisher(for: Notification.Name("peerStatusUpdated"))
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+
+        chatViewModel.participantTracker.$visiblePeople
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+
+        locationChannelsModel.$selectedChannel
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+
+        locationChannelsModel.$teleported
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+
+        locationChannelsModel.$availableChannels
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refresh()
+            }
+            .store(in: &cancellables)
+    }
+
+    private func refresh() {
+        let myPeerID = chatViewModel.meshService.myPeerID
+        let meshRows = allPeers.map { peer in
+            let isMe = peer.peerID == myPeerID
+            let fingerprint = isMe ? nil : chatViewModel.getFingerprint(for: peer.peerID)
+            let isVerifiedFingerprint = fingerprint.map { peerIdentityStore.isVerified($0) } ?? false
+            let verifiedBadge = !peer.isConnected && isVerifiedFingerprint
+            // Vouched is subordinate to verified: never show both seals.
+            let vouchedBadge = !isVerifiedFingerprint
+                && (fingerprint.map { chatViewModel.isVouchedFingerprint($0) } ?? false)
+
+            return MeshPeerRow(
+                peerID: peer.peerID,
+                displayName: isMe ? chatViewModel.nickname : peer.nickname,
+                isMe: isMe,
+                hasUnread: chatViewModel.hasUnreadMessages(for: peer.peerID),
+                isBlocked: !isMe && chatViewModel.isPeerBlocked(peer.peerID),
+                isFavorite: peer.favoriteStatus?.isFavorite ?? false,
+                isConnected: peer.isConnected,
+                isReachable: peer.isReachable,
+                isMutualFavorite: peer.isMutualFavorite,
+                encryptionStatus: chatViewModel.getEncryptionStatus(for: peer.peerID),
+                showsVerifiedBadgeWhenOffline: verifiedBadge,
+                showsVouchedBadge: vouchedBadge
+            )
+        }
+
+        let meshCounts = meshRows.reduce(into: (reachable: 0, connected: 0)) { counts, row in
+            guard !row.isMe else { return }
+            if row.isConnected {
+                counts.connected += 1
+                counts.reachable += 1
+            } else if row.isReachable {
+                counts.reachable += 1
+            }
+        }
+
+        let geohashPeople = buildGeohashPeople()
+        let groupRows = buildGroupRows()
+
+        self.meshRows = meshRows
+        reachableMeshPeerCount = meshCounts.reachable
+        connectedMeshPeerCount = meshCounts.connected
+        self.geohashPeople = geohashPeople
+        visibleGeohashPeerCount = geohashPeople.count
+        self.groupRows = groupRows
+        renderID = (
+            meshRows.map {
+                "\($0.id)-\($0.isConnected)-\($0.isReachable)-\($0.hasUnread)-\($0.isFavorite)-\($0.isBlocked)"
+            } +
+            geohashPeople.map {
+                "geo:\($0.id)-\($0.isTeleported)-\($0.isBlocked)-\($0.displayName)"
+            } +
+            groupRows.map {
+                "group:\($0.id)-\($0.name)-\($0.memberCount)-\($0.hasUnread)"
+            }
+        ).joined(separator: "|")
+    }
+
+    private func buildGroupRows() -> [GroupChatRow] {
+        let myFingerprint = chatViewModel.meshService.noiseIdentityFingerprint()
+        return chatViewModel.groupStore.groups.map { group in
+            GroupChatRow(
+                peerID: group.peerID,
+                name: group.name,
+                memberCount: group.members.count,
+                isCreator: group.creatorFingerprint == myFingerprint,
+                hasUnread: chatViewModel.hasUnreadMessages(for: group.peerID)
+            )
+        }
+    }
+
+    private func buildGeohashPeople() -> [GeohashPersonRow] {
+        let myHex = currentGeohashIdentityHex()
+        let teleportedSet = Set(locationPresenceStore.teleportedGeo.map { $0.lowercased() })
+
+        return chatViewModel.visibleGeohashPeople().map { person in
+            let isMe = person.id == myHex
+            return GeohashPersonRow(
+                id: person.id,
+                displayName: person.displayName,
+                isMe: isMe,
+                isTeleported: teleportedSet.contains(person.id.lowercased()) || (isMe && locationChannelsModel.teleported),
+                isBlocked: !isMe && chatViewModel.isGeohashUserBlocked(pubkeyHexLowercased: person.id)
+            )
+        }
+    }
+
+    private func currentGeohashIdentityHex() -> String? {
+        guard case .location(let channel) = locationChannelsModel.selectedChannel,
+              let identity = try? chatViewModel.idBridge.deriveIdentity(forGeohash: channel.geohash) else {
+            return nil
+        }
+
+        return identity.publicKeyHex.lowercased()
+    }
+}

bitchat/App/PrivateConversationModels.swift

@@ -0,0 +1,362 @@
+import BitFoundation
+import Combine
+import Foundation
+
+/// Feature model for private (direct) conversations.
+///
+/// Reads the single-writer `ConversationStore` directly: `messages(for:)`
+/// returns the peer's conversation backing array (no mirror dictionary), and
+/// the store's typed `changes` subject drives invalidation — a change in the
+/// SELECTED peer's conversation republishes this model, while appends to
+/// other private chats only surface through the unread set. Direct
+/// conversations are keyed by raw routing peer ID; the coordinators'
+/// ephemeral/stable mirroring guarantees the selected peer's key always
+/// holds the full timeline (see `ConversationID.directPeer`).
+@MainActor
+final class PrivateInboxModel: ObservableObject {
+    @Published private(set) var selectedPeerID: PeerID?
+    @Published private(set) var unreadPeerIDs: Set<PeerID> = []
+
+    private let conversations: ConversationStore
+    private var cancellables = Set<AnyCancellable>()
+
+    init(conversations: ConversationStore) {
+        self.conversations = conversations
+        self.selectedPeerID = conversations.selectedPrivatePeerID
+        self.unreadPeerIDs = conversations.unreadDirectRoutingPeerIDs()
+
+        bind()
+    }
+
+    func messages(for peerID: PeerID?) -> [BitchatMessage] {
+        guard let peerID else { return [] }
+        return conversations.conversationsByID[.directPeer(peerID)]?.messages ?? []
+    }
+
+    private func bind() {
+        conversations.$selectedPrivatePeerID
+            .dropFirst()
+            .sink { [weak self] peerID in
+                guard let self, self.selectedPeerID != peerID else { return }
+                self.selectedPeerID = peerID
+            }
+            .store(in: &cancellables)
+
+        conversations.changes
+            .sink { [weak self] change in
+                self?.apply(change)
+            }
+            .store(in: &cancellables)
+    }
+
+    private func apply(_ change: ConversationChange) {
+        switch change {
+        case .appended(let id, _),
+             .updated(let id, _),
+             .statusChanged(let id, _, _),
+             .messageRemoved(let id, _),
+             .cleared(let id):
+            republishIfSelected(id)
+
+        case .unreadChanged(let id, _):
+            guard isDirect(id) else { return }
+            refreshUnreadPeerIDs()
+
+        case .removed(let id):
+            guard isDirect(id) else { return }
+            refreshUnreadPeerIDs()
+            republishIfSelected(id)
+
+        case .migrated(let source, let destination):
+            guard isDirect(source) || isDirect(destination) else { return }
+            refreshUnreadPeerIDs()
+            republishIfSelected(source)
+            republishIfSelected(destination)
+        }
+    }
+
+    private func republishIfSelected(_ id: ConversationID) {
+        guard let selectedPeerID, id == .directPeer(selectedPeerID) else { return }
+        objectWillChange.send()
+    }
+
+    private func refreshUnreadPeerIDs() {
+        let next = conversations.unreadDirectRoutingPeerIDs()
+        guard unreadPeerIDs != next else { return }
+        unreadPeerIDs = next
+    }
+
+    private func isDirect(_ id: ConversationID) -> Bool {
+        if case .direct = id { return true }
+        return false
+    }
+}
+
+enum PrivateConversationAvailability: Equatable {
+    case bluetoothConnected
+    case meshReachable
+    case nostrAvailable
+    case offline
+}
+
+struct PrivateConversationHeaderState: Equatable {
+    let conversationPeerID: PeerID
+    let headerPeerID: PeerID
+    let displayName: String
+    let availability: PrivateConversationAvailability
+    let isFavorite: Bool
+    let encryptionStatus: EncryptionStatus?
+
+    var supportsFavoriteToggle: Bool {
+        !conversationPeerID.isGeoDM && !conversationPeerID.isGroup
+    }
+
+    /// Group chats have no single peer identity behind the header: no
+    /// fingerprint screen, no per-peer encryption badge.
+    var isGroupConversation: Bool {
+        conversationPeerID.isGroup
+    }
+}
+
+@MainActor
+final class PrivateConversationModel: ObservableObject {
+    @Published private(set) var selectedPeerID: PeerID?
+    @Published private(set) var selectedHeaderState: PrivateConversationHeaderState?
+
+    private let chatViewModel: ChatViewModel
+    private let conversations: ConversationStore
+    private let locationChannelsModel: LocationChannelsModel
+    private let peerIdentityStore: PeerIdentityStore
+    private var cancellables = Set<AnyCancellable>()
+
+    init(
+        chatViewModel: ChatViewModel,
+        conversations: ConversationStore,
+        locationChannelsModel: LocationChannelsModel? = nil,
+        peerIdentityStore: PeerIdentityStore? = nil
+    ) {
+        self.chatViewModel = chatViewModel
+        self.conversations = conversations
+        self.locationChannelsModel = locationChannelsModel ?? LocationChannelsModel()
+        self.peerIdentityStore = peerIdentityStore ?? chatViewModel.peerIdentityStore
+        let initialPeerID = conversations.selectedPrivatePeerID
+        self.selectedPeerID = initialPeerID
+        self.selectedHeaderState = initialPeerID.flatMap { peerID in
+            makeHeaderState(for: peerID)
+        }
+
+        bind()
+    }
+
+    func startConversation(with peerID: PeerID) {
+        chatViewModel.startPrivateChat(with: peerID)
+        refreshSelectedConversation()
+    }
+
+    func openConversation(for peerID: PeerID) {
+        if peerID.isGeoChat {
+            guard let full = chatViewModel.fullNostrHex(forSenderPeerID: peerID) else { return }
+            chatViewModel.startGeohashDM(withPubkeyHex: full)
+        } else {
+            chatViewModel.startPrivateChat(with: peerID)
+        }
+
+        refreshSelectedConversation()
+    }
+
+    func endConversation() {
+        chatViewModel.endPrivateChat()
+        refreshSelectedConversation()
+    }
+
+    func toggleFavorite(peerID: PeerID) {
+        chatViewModel.toggleFavorite(peerID: peerID)
+        refreshSelectedConversation()
+    }
+
+    func toggleFavoriteForSelectedConversation() {
+        guard let headerPeerID = selectedHeaderState?.headerPeerID else { return }
+        toggleFavorite(peerID: headerPeerID)
+    }
+
+    func markMessagesAsRead(from peerID: PeerID) {
+        chatViewModel.markPrivateMessagesAsRead(from: peerID)
+    }
+
+    private func bind() {
+        conversations.$selectedPrivatePeerID
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refreshSelectedConversation()
+            }
+            .store(in: &cancellables)
+
+        chatViewModel.$allPeers
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refreshSelectedConversation()
+            }
+            .store(in: &cancellables)
+
+        peerIdentityStore.$encryptionStatuses
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refreshSelectedConversation()
+            }
+            .store(in: &cancellables)
+
+        NotificationCenter.default.publisher(for: .favoriteStatusChanged)
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refreshSelectedConversation()
+            }
+            .store(in: &cancellables)
+
+        chatViewModel.groupStore.$groups
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refreshSelectedConversation()
+            }
+            .store(in: &cancellables)
+
+        NotificationCenter.default.publisher(for: Notification.Name("peerStatusUpdated"))
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refreshSelectedConversation()
+            }
+            .store(in: &cancellables)
+
+        locationChannelsModel.$selectedChannel
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.refreshSelectedConversation()
+            }
+            .store(in: &cancellables)
+    }
+
+    private func refreshSelectedConversation() {
+        selectedPeerID = conversations.selectedPrivatePeerID
+        selectedHeaderState = selectedPeerID.flatMap { peerID in
+            makeHeaderState(for: peerID)
+        }
+    }
+
+    private func makeHeaderState(for conversationPeerID: PeerID) -> PrivateConversationHeaderState {
+        // Group chats: the "peer" is the whole crew. Name + member count in
+        // the header; availability reads as mesh since group traffic floods
+        // the local mesh, and the per-peer encryption badge does not apply.
+        if conversationPeerID.isGroup {
+            let displayName: String
+            if let group = chatViewModel.groupStore.group(for: conversationPeerID) {
+                displayName = "#\(group.name) (\(group.members.count))"
+            } else {
+                displayName = String(localized: "common.unknown", comment: "Fallback label for unknown peer")
+            }
+            return PrivateConversationHeaderState(
+                conversationPeerID: conversationPeerID,
+                headerPeerID: conversationPeerID,
+                displayName: displayName,
+                availability: .meshReachable,
+                isFavorite: false,
+                encryptionStatus: nil
+            )
+        }
+
+        let headerPeerID = chatViewModel.getShortIDForNoiseKey(conversationPeerID)
+        let peer = chatViewModel.getPeer(byID: headerPeerID)
+        let displayName = resolveDisplayName(for: conversationPeerID, headerPeerID: headerPeerID, peer: peer)
+        // Geo DMs are always routed over Nostr (NIP-17); their nostr_ keys
+        // never resolve to a reachable mesh peer, so resolveAvailability would
+        // report .offline. Report .nostrAvailable so the header shows the
+        // globe instead of a misleading "offline" tag.
+        let availability = conversationPeerID.isGeoDM
+            ? .nostrAvailable
+            : resolveAvailability(for: headerPeerID, peer: peer)
+        let encryptionStatus: EncryptionStatus? = conversationPeerID.isGeoDM
+            ? nil
+            : chatViewModel.getEncryptionStatus(for: headerPeerID)
+
+        return PrivateConversationHeaderState(
+            conversationPeerID: conversationPeerID,
+            headerPeerID: headerPeerID,
+            displayName: displayName,
+            availability: availability,
+            isFavorite: chatViewModel.isFavorite(peerID: headerPeerID),
+            encryptionStatus: encryptionStatus
+        )
+    }
+
+    private func resolveDisplayName(
+        for conversationPeerID: PeerID,
+        headerPeerID: PeerID,
+        peer: BitchatPeer?
+    ) -> String {
+        if conversationPeerID.isGeoDM, case .location(let channel) = locationChannelsModel.selectedChannel {
+            return "#\(channel.geohash)/@\(chatViewModel.geohashDisplayName(for: conversationPeerID))"
+        }
+        if let displayName = peer?.displayName {
+            return displayName
+        }
+        if let nickname = chatViewModel.meshService.peerNickname(peerID: headerPeerID) {
+            return nickname
+        }
+        if let favorite = FavoritesPersistenceService.shared.getFavoriteStatus(
+            for: Data(hexString: headerPeerID.id) ?? Data()
+        ), !favorite.peerNickname.isEmpty {
+            return favorite.peerNickname
+        }
+        if headerPeerID.id.count == 16 {
+            let candidates = chatViewModel.identityManager.getCryptoIdentitiesByPeerIDPrefix(headerPeerID)
+            if let identity = candidates.first,
+               let social = chatViewModel.identityManager.getSocialIdentity(for: identity.fingerprint) {
+                if let pet = social.localPetname, !pet.isEmpty {
+                    return pet
+                }
+                if !social.claimedNickname.isEmpty {
+                    return social.claimedNickname
+                }
+            }
+        } else if let noiseKey = headerPeerID.noiseKey {
+            let fingerprint = noiseKey.sha256Fingerprint()
+            if let social = chatViewModel.identityManager.getSocialIdentity(for: fingerprint) {
+                if let pet = social.localPetname, !pet.isEmpty {
+                    return pet
+                }
+                if !social.claimedNickname.isEmpty {
+                    return social.claimedNickname
+                }
+            }
+        }
+
+        return String(localized: "common.unknown", comment: "Fallback label for unknown peer")
+    }
+
+    private func resolveAvailability(for headerPeerID: PeerID, peer: BitchatPeer?) -> PrivateConversationAvailability {
+        if let connectionState = peer?.connectionState {
+            switch connectionState {
+            case .bluetoothConnected:
+                return .bluetoothConnected
+            case .meshReachable:
+                return .meshReachable
+            case .nostrAvailable:
+                return .nostrAvailable
+            case .offline:
+                return .offline
+            }
+        }
+
+        if chatViewModel.meshService.isPeerReachable(headerPeerID) {
+            return .meshReachable
+        }
+        if let noiseKey = Data(hexString: headerPeerID.id),
+           let favoriteStatus = FavoritesPersistenceService.shared.getFavoriteStatus(for: noiseKey),
+           favoriteStatus.isMutual {
+            return .nostrAvailable
+        }
+        if chatViewModel.meshService.isPeerConnected(headerPeerID) || chatViewModel.connectedPeers.contains(headerPeerID) {
+            return .bluetoothConnected
+        }
+
+        return .offline
+    }
+}

bitchat/App/PublicChatModel.swift

@@ -0,0 +1,77 @@
+import BitFoundation
+import Combine
+import SwiftUI
+
+/// Feature model for the active public (mesh/geohash) timeline.
+///
+/// Observes ONE `Conversation` object in the single-writer
+/// `ConversationStore` — the active channel's — so appends to background
+/// conversations (other geohashes, private chats) never invalidate it.
+/// `messages` reads the observed conversation's backing array directly;
+/// there is no mirror copy.
+@MainActor
+final class PublicChatModel: ObservableObject {
+    @Published private(set) var activeChannel: ChannelID
+
+    /// The active public conversation's timeline.
+    var messages: [BitchatMessage] { activeConversation.messages }
+
+    private let conversations: ConversationStore
+    private var activeConversation: Conversation
+    private var activeConversationCancellable: AnyCancellable?
+    private var cancellables = Set<AnyCancellable>()
+
+    init(conversations: ConversationStore) {
+        let channel = conversations.activeChannel
+        self.conversations = conversations
+        self.activeChannel = channel
+        self.activeConversation = conversations.conversation(for: ConversationID(channelID: channel))
+
+        observeActiveConversation()
+        bind()
+    }
+
+    private func bind() {
+        conversations.$activeChannel
+            .dropFirst()
+            .sink { [weak self] channel in
+                guard let self else { return }
+                self.activeChannel = channel
+                self.retargetActiveConversation(to: channel)
+            }
+            .store(in: &cancellables)
+
+        // The store replaces a conversation's object when it is removed
+        // (panic clear); retarget to the fresh instance so the observation
+        // never goes stale.
+        conversations.changes
+            .sink { [weak self] change in
+                guard let self,
+                      case .removed(let id) = change,
+                      id == self.activeConversation.id else { return }
+                self.retargetActiveConversation(to: self.activeChannel)
+            }
+            .store(in: &cancellables)
+    }
+
+    private func retargetActiveConversation(to channel: ChannelID) {
+        let conversation = conversations.conversation(for: ConversationID(channelID: channel))
+        guard conversation !== activeConversation else {
+            // Same object (e.g. re-selected channel): keep the existing
+            // observation, but `messages` may still differ from what views
+            // last rendered, so republish.
+            objectWillChange.send()
+            return
+        }
+        objectWillChange.send()
+        activeConversation = conversation
+        observeActiveConversation()
+    }
+
+    private func observeActiveConversation() {
+        activeConversationCancellable = activeConversation.objectWillChange
+            .sink { [weak self] _ in
+                self?.objectWillChange.send()
+            }
+    }
+}

bitchat/App/VerificationModel.swift

@@ -0,0 +1,191 @@
+import BitFoundation
+import Combine
+import Foundation
+
+struct FingerprintPresentationState: Equatable {
+    let statusPeerID: PeerID
+    let peerNickname: String
+    let encryptionStatus: EncryptionStatus
+    let theirFingerprint: String?
+    let myFingerprint: String
+    let isVerified: Bool
+    /// Number of currently-valid vouches from peers the user verified
+    /// (0 when the peer is explicitly verified — the stronger badge wins).
+    let voucherCount: Int
+    /// Display names of the (verified) vouchers, where known.
+    let voucherNames: [String]
+
+    /// Vouched for by ≥1 peer the user verified (and not explicitly verified).
+    var isVouched: Bool { voucherCount > 0 }
+
+    var canToggleVerification: Bool {
+        encryptionStatus == .noiseSecured || encryptionStatus == .noiseVerified
+    }
+}
+
+enum VerificationScanOutcome: Equatable {
+    case requested(String)
+    case notFound
+    case invalid
+}
+
+@MainActor
+final class VerificationModel: ObservableObject {
+    @Published private(set) var currentNickname: String
+    @Published private(set) var selectedPeerID: PeerID?
+
+    private let chatViewModel: ChatViewModel
+    private let peerIdentityStore: PeerIdentityStore
+    private var cancellables = Set<AnyCancellable>()
+
+    init(
+        chatViewModel: ChatViewModel,
+        privateConversationModel: PrivateConversationModel,
+        peerIdentityStore: PeerIdentityStore? = nil
+    ) {
+        self.chatViewModel = chatViewModel
+        self.peerIdentityStore = peerIdentityStore ?? chatViewModel.peerIdentityStore
+        self.currentNickname = chatViewModel.nickname
+        self.selectedPeerID = privateConversationModel.selectedPeerID
+
+        bind(privateConversationModel: privateConversationModel)
+    }
+
+    func myQRString() -> String {
+        let npub = try? chatViewModel.idBridge.getCurrentNostrIdentity()?.npub
+        return VerificationService.shared.buildMyQRString(nickname: currentNickname, npub: npub) ?? ""
+    }
+
+    func beginQRVerification(with qr: VerificationService.VerificationQR) -> Bool {
+        chatViewModel.beginQRVerification(with: qr)
+    }
+
+    func verifyScannedPayload(_ payload: String) -> VerificationScanOutcome {
+        guard let qr = VerificationService.shared.verifyScannedQR(payload) else {
+            return .invalid
+        }
+
+        guard chatViewModel.beginQRVerification(with: qr) else {
+            return .notFound
+        }
+
+        return .requested(qr.nickname)
+    }
+
+    func verifyFingerprint(for peerID: PeerID) {
+        chatViewModel.verifyFingerprint(for: peerID)
+    }
+
+    func unverifyFingerprint(for peerID: PeerID) {
+        chatViewModel.unverifyFingerprint(for: peerID)
+    }
+
+    func isVerified(peerID: PeerID) -> Bool {
+        guard let fingerprint = chatViewModel.getFingerprint(for: peerID) else { return false }
+        return peerIdentityStore.isVerified(fingerprint)
+    }
+
+    func fingerprintPresentation(for peerID: PeerID) -> FingerprintPresentationState {
+        let statusPeerID = chatViewModel.getShortIDForNoiseKey(peerID)
+        let encryptionStatus = chatViewModel.getEncryptionStatus(for: statusPeerID)
+        let theirFingerprint = chatViewModel.getFingerprint(for: statusPeerID)
+        let peerNickname = resolveDisplayName(for: peerID, statusPeerID: statusPeerID)
+        let isVerified = theirFingerprint.map { peerIdentityStore.isVerified($0) } ?? false
+
+        // Vouch state is recomputed on read: only vouchers still in the
+        // verified set count, so removing a verification silently retires the
+        // vouches that peer gave.
+        let vouchers: [VouchRecord]
+        if !isVerified, let theirFingerprint {
+            vouchers = chatViewModel.identityManager.validVouchers(for: theirFingerprint)
+        } else {
+            vouchers = []
+        }
+        let voucherNames = vouchers.compactMap { record -> String? in
+            guard let social = chatViewModel.identityManager.getSocialIdentity(for: record.voucherFingerprint) else {
+                return nil
+            }
+            if let petname = social.localPetname, !petname.isEmpty { return petname }
+            return social.claimedNickname.isEmpty ? nil : social.claimedNickname
+        }
+
+        return FingerprintPresentationState(
+            statusPeerID: statusPeerID,
+            peerNickname: peerNickname,
+            encryptionStatus: encryptionStatus,
+            theirFingerprint: theirFingerprint,
+            myFingerprint: chatViewModel.getMyFingerprint(),
+            isVerified: isVerified,
+            voucherCount: vouchers.count,
+            voucherNames: voucherNames
+        )
+    }
+
+    private func bind(privateConversationModel: PrivateConversationModel) {
+        chatViewModel.$nickname
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$currentNickname)
+
+        privateConversationModel.$selectedPeerID
+            .receive(on: DispatchQueue.main)
+            .assign(to: &$selectedPeerID)
+
+        peerIdentityStore.$encryptionStatuses
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.objectWillChange.send()
+            }
+            .store(in: &cancellables)
+
+        peerIdentityStore.$verifiedFingerprints
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.objectWillChange.send()
+            }
+            .store(in: &cancellables)
+
+        chatViewModel.$allPeers
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.objectWillChange.send()
+            }
+            .store(in: &cancellables)
+
+        // Vouch state changes (ChatVouchCoordinator.notifyPeerTrustChanged)
+        // are signalled via this notification rather than a published
+        // property, so an open fingerprint sheet refreshes its vouched badge
+        // live when a vouch batch is accepted.
+        NotificationCenter.default.publisher(for: Notification.Name("peerStatusUpdated"))
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in
+                self?.objectWillChange.send()
+            }
+            .store(in: &cancellables)
+    }
+
+    private func resolveDisplayName(for peerID: PeerID, statusPeerID: PeerID) -> String {
+        if let peer = chatViewModel.getPeer(byID: statusPeerID) {
+            return peer.displayName
+        }
+        if let name = chatViewModel.meshService.peerNickname(peerID: statusPeerID) {
+            return name
+        }
+        if let data = peerID.noiseKey {
+            if let favorite = FavoritesPersistenceService.shared.getFavoriteStatus(for: data),
+               !favorite.peerNickname.isEmpty {
+                return favorite.peerNickname
+            }
+            let fingerprint = data.sha256Fingerprint()
+            if let social = chatViewModel.identityManager.getSocialIdentity(for: fingerprint) {
+                if let pet = social.localPetname, !pet.isEmpty {
+                    return pet
+                }
+                if !social.claimedNickname.isEmpty {
+                    return social.claimedNickname
+                }
+            }
+        }
+
+        return String(localized: "common.unknown", comment: "Label for an unknown peer")
+    }
+}

bitchat/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -1,111 +1,9 @@
 {
   "images" : [
-    {
-      "filename" : "icon_20x20@2x.png",
-      "idiom" : "iphone",
-      "scale" : "2x",
-      "size" : "20x20"
-    },
-    {
-      "filename" : "icon_20x20@3x.png",
-      "idiom" : "iphone",
-      "scale" : "3x",
-      "size" : "20x20"
-    },
-    {
-      "filename" : "icon_29x29@2x.png",
-      "idiom" : "iphone",
-      "scale" : "2x",
-      "size" : "29x29"
-    },
-    {
-      "filename" : "icon_29x29@3x.png",
-      "idiom" : "iphone",
-      "scale" : "3x",
-      "size" : "29x29"
-    },
-    {
-      "filename" : "icon_40x40@2x.png",
-      "idiom" : "iphone",
-      "scale" : "2x",
-      "size" : "40x40"
-    },
-    {
-      "filename" : "icon_40x40@3x.png",
-      "idiom" : "iphone",
-      "scale" : "3x",
-      "size" : "40x40"
-    },
-    {
-      "filename" : "icon_60x60@2x.png",
-      "idiom" : "iphone",
-      "scale" : "2x",
-      "size" : "60x60"
-    },
-    {
-      "filename" : "icon_60x60@3x.png",
-      "idiom" : "iphone",
-      "scale" : "3x",
-      "size" : "60x60"
-    },
-    {
-      "filename" : "icon_20x20.png",
-      "idiom" : "ipad",
-      "scale" : "1x",
-      "size" : "20x20"
-    },
-    {
-      "filename" : "icon_20x20@2x.png",
-      "idiom" : "ipad",
-      "scale" : "2x",
-      "size" : "20x20"
-    },
-    {
-      "filename" : "icon_29x29.png",
-      "idiom" : "ipad",
-      "scale" : "1x",
-      "size" : "29x29"
-    },
-    {
-      "filename" : "icon_29x29@2x.png",
-      "idiom" : "ipad",
-      "scale" : "2x",
-      "size" : "29x29"
-    },
-    {
-      "filename" : "icon_40x40.png",
-      "idiom" : "ipad",
-      "scale" : "1x",
-      "size" : "40x40"
-    },
-    {
-      "filename" : "icon_40x40@2x.png",
-      "idiom" : "ipad",
-      "scale" : "2x",
-      "size" : "40x40"
-    },
-    {
-      "filename" : "icon_76x76.png",
-      "idiom" : "ipad",
-      "scale" : "1x",
-      "size" : "76x76"
-    },
-    {
-      "filename" : "icon_76x76@2x.png",
-      "idiom" : "ipad",
-      "scale" : "2x",
-      "size" : "76x76"
-    },
-    {
-      "filename" : "icon_83.5x83.5@2x.png",
-      "idiom" : "ipad",
-      "scale" : "2x",
-      "size" : "83.5x83.5"
-    },
     {
       "filename" : "icon_1024x1024.png",
-      "idiom" : "ios-marketing",
-      "scale" : "1x",
+      "idiom" : "universal",
+      "platform" : "ios",
       "size" : "1024x1024"
     },
     {

bitchat/Assets.xcassets/AppIconDebug.appiconset/Contents.json

@@ -0,0 +1,36 @@
+{
+  "images" : [
+    {
+      "filename" : "image-1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "tinted"
+        }
+      ],
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

bitchat/Assets.xcassets/Contents.json

@@ -3,4 +3,4 @@
     "author" : "xcode",
     "version" : 1
   }
-}
+}

bitchat/BitchatApp.swift

@@ -8,48 +8,63 @@
 
 import SwiftUI
 import UserNotifications
+#if DEBUG
+import BitLogger
+#endif
 
 @main
 struct BitchatApp: App {
-    @StateObject private var chatViewModel = ChatViewModel()
+    static let bundleID = Bundle.main.bundleIdentifier ?? "chat.bitchat"
+    static let groupID = "group.\(bundleID)"
+
+    @StateObject private var runtime: AppRuntime
+    @AppStorage(AppTheme.storageKey) private var appThemeRawValue = AppTheme.matrix.rawValue
     #if os(iOS)
+    @Environment(\.scenePhase) var scenePhase
     @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
     #elseif os(macOS)
     @NSApplicationDelegateAdaptor(MacAppDelegate.self) var appDelegate
     #endif
-    
+
     init() {
+        _runtime = StateObject(wrappedValue: AppRuntime())
         UNUserNotificationCenter.current().delegate = NotificationDelegate.shared
     }
-    
+
     var body: some Scene {
         WindowGroup {
             ContentView()
-                .environmentObject(chatViewModel)
+                .environment(\.appTheme, AppTheme(rawValue: appThemeRawValue) ?? .matrix)
+                .environmentObject(runtime.publicChatModel)
+                .environmentObject(runtime.privateInboxModel)
+                .environmentObject(runtime.privateConversationModel)
+                .environmentObject(runtime.verificationModel)
+                .environmentObject(runtime.conversationUIModel)
+                .environmentObject(runtime.locationChannelsModel)
+                .environmentObject(runtime.peerListModel)
+                .environmentObject(runtime.appChromeModel)
                 .onAppear {
-                    NotificationDelegate.shared.chatViewModel = chatViewModel
-                    #if os(iOS)
-                    appDelegate.chatViewModel = chatViewModel
-                    #elseif os(macOS)
-                    appDelegate.chatViewModel = chatViewModel
+                    appDelegate.runtime = runtime
+                    runtime.start()
+                    #if DEBUG
+                    // Arm the opt-in UDP log sink from persisted config (no-op
+                    // until a collector host is set in the App Info sheet).
+                    LogNetworkSink.shared.reloadConfiguration()
                     #endif
-                    // Check for shared content
-                    checkForSharedContent()
                 }
                 .onOpenURL { url in
-                    handleURL(url)
+                    runtime.handleOpenURL(url)
                 }
                 #if os(iOS)
+                .onChange(of: scenePhase) { newPhase in
+                    runtime.handleScenePhaseChange(newPhase)
+                }
                 .onReceive(NotificationCenter.default.publisher(for: UIApplication.didBecomeActiveNotification)) { _ in
-                    // Check for shared content when app becomes active
-                    checkForSharedContent()
-                    // Notify MessageRouter to check for Nostr messages
-                    NotificationCenter.default.post(name: .appDidBecomeActive, object: nil)
+                    runtime.handleDidBecomeActiveNotification()
                 }
                 #elseif os(macOS)
                 .onReceive(NotificationCenter.default.publisher(for: NSApplication.didBecomeActiveNotification)) { _ in
-                    // Notify MessageRouter to check for Nostr messages
-                    NotificationCenter.default.post(name: .appDidBecomeActive, object: nil)
+                    runtime.handleMacDidBecomeActiveNotification()
                 }
                 #endif
         }
@@ -58,74 +73,18 @@ struct BitchatApp: App {
         .windowResizability(.contentSize)
         #endif
     }
-    
-    private func handleURL(_ url: URL) {
-        if url.scheme == "bitchat" && url.host == "share" {
-            // Handle shared content
-            checkForSharedContent()
-        }
-    }
-    
-    private func checkForSharedContent() {
-        // Check app group for shared content from extension
-        guard let userDefaults = UserDefaults(suiteName: "group.chat.bitchat") else {
-            return
-        }
-        
-        guard let sharedContent = userDefaults.string(forKey: "sharedContent"),
-              let sharedDate = userDefaults.object(forKey: "sharedContentDate") as? Date else {
-            return
-        }
-        
-        // Only process if shared within last 30 seconds
-        if Date().timeIntervalSince(sharedDate) < 30 {
-            let contentType = userDefaults.string(forKey: "sharedContentType") ?? "text"
-            
-            // Clear the shared content
-            userDefaults.removeObject(forKey: "sharedContent")
-            userDefaults.removeObject(forKey: "sharedContentType")
-            userDefaults.removeObject(forKey: "sharedContentDate")
-            userDefaults.synchronize()
-            
-            // Show notification about shared content
-            DispatchQueue.main.async {
-                // Add system message about sharing
-                let systemMessage = BitchatMessage(
-                    sender: "system",
-                    content: "preparing to share \(contentType)...",
-                    timestamp: Date(),
-                    isRelay: false
-                )
-                self.chatViewModel.messages.append(systemMessage)
-            }
-            
-            // Send the shared content after a short delay
-            DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
-                if contentType == "url" {
-                    // Try to parse as JSON first
-                    if let data = sharedContent.data(using: .utf8),
-                       let urlData = try? JSONSerialization.jsonObject(with: data) as? [String: String],
-                       let url = urlData["url"] {
-                        // Send plain URL
-                        self.chatViewModel.sendMessage(url)
-                    } else {
-                        // Fallback to simple URL
-                        self.chatViewModel.sendMessage(sharedContent)
-                    }
-                } else {
-                    self.chatViewModel.sendMessage(sharedContent)
-                }
-            }
-        }
-    }
 }
 
 #if os(iOS)
-class AppDelegate: NSObject, UIApplicationDelegate {
-    weak var chatViewModel: ChatViewModel?
-    
-    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
-        return true
+final class AppDelegate: NSObject, UIApplicationDelegate {
+    weak var runtime: AppRuntime?
+
+    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? = nil) -> Bool {
+        true
+    }
+
+    func applicationWillTerminate(_ application: UIApplication) {
+        runtime?.applicationWillTerminate()
     }
 }
 #endif
@@ -133,63 +92,43 @@ class AppDelegate: NSObject, UIApplicationDelegate {
 #if os(macOS)
 import AppKit
 
-class MacAppDelegate: NSObject, NSApplicationDelegate {
-    weak var chatViewModel: ChatViewModel?
-    
+final class MacAppDelegate: NSObject, NSApplicationDelegate {
+    weak var runtime: AppRuntime?
+
     func applicationWillTerminate(_ notification: Notification) {
-        chatViewModel?.applicationWillTerminate()
+        runtime?.applicationWillTerminate()
     }
-    
+
     func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
-        return true
+        true
     }
 }
 #endif
 
-class NotificationDelegate: NSObject, UNUserNotificationCenterDelegate {
+final class NotificationDelegate: NSObject, UNUserNotificationCenterDelegate {
     static let shared = NotificationDelegate()
-    weak var chatViewModel: ChatViewModel?
-    
+    weak var runtime: AppRuntime?
+
     func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
         let identifier = response.notification.request.identifier
         let userInfo = response.notification.request.content.userInfo
-        
-        // Check if this is a private message notification
-        if identifier.hasPrefix("private-") {
-            // Get peer ID from userInfo
-            if let peerID = userInfo["peerID"] as? String {
-                DispatchQueue.main.async {
-                    self.chatViewModel?.startPrivateChat(with: peerID)
-                }
-            }
+
+        Task { @MainActor in
+            self.runtime?.handleNotificationResponse(identifier: identifier, userInfo: userInfo)
         }
-        
         completionHandler()
     }
-    
+
     func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
         let identifier = notification.request.identifier
         let userInfo = notification.request.content.userInfo
-        
-        // Check if this is a private message notification
-        if identifier.hasPrefix("private-") {
-            // Get peer ID from userInfo
-            if let peerID = userInfo["peerID"] as? String {
-                // Don't show notification if the private chat is already open
-                if chatViewModel?.selectedPrivateChatPeer == peerID {
-                    completionHandler([])
-                    return
-                }
-            }
+
+        Task {
+            let options = await self.runtime?.presentationOptions(
+                forNotificationIdentifier: identifier,
+                userInfo: userInfo
+            ) ?? [.banner, .sound]
+            completionHandler(options)
         }
-        
-        // Show notification in all other cases
-        completionHandler([.banner, .sound])
     }
 }
-
-extension String {
-    var nilIfEmpty: String? {
-        self.isEmpty ? nil : self
-    }
-}

bitchat/Features/media/ImageUtils.swift

@@ -0,0 +1,217 @@
+import Foundation
+import ImageIO
+import UniformTypeIdentifiers
+#if os(iOS)
+import UIKit
+#else
+import AppKit
+#endif
+
+enum ImageUtilsError: Error {
+    case invalidImage
+    case encodingFailed
+}
+
+enum ImageUtils {
+    private static let compressionQuality: CGFloat = 0.82
+    private static let targetImageBytes: Int = 45_000
+    private static let maxSourceImageBytes: Int = 10 * 1024 * 1024
+
+    static func processImage(at url: URL, maxDimension: CGFloat = 448, outputDirectory: URL? = nil) throws -> URL {
+        try validateImageSource(at: url)
+
+        let data = try Data(contentsOf: url)
+        #if os(iOS)
+        guard let image = UIImage(data: data) else { throw ImageUtilsError.invalidImage }
+        return try processImage(image, maxDimension: maxDimension, outputDirectory: outputDirectory)
+        #else
+        guard let image = NSImage(data: data) else { throw ImageUtilsError.invalidImage }
+        return try processImage(image, maxDimension: maxDimension, outputDirectory: outputDirectory)
+        #endif
+    }
+
+    static func validateImageSource(at url: URL) throws {
+        // Security H1: Check file size BEFORE reading into memory.
+        let attrs = try FileManager.default.attributesOfItem(atPath: url.path)
+        guard let fileSize = attrs[.size] as? Int,
+              fileSize > 0,
+              fileSize <= maxSourceImageBytes else {
+            throw ImageUtilsError.invalidImage
+        }
+
+        let options = [kCGImageSourceShouldCache: false] as CFDictionary
+        guard let source = CGImageSourceCreateWithURL(url as CFURL, options),
+              CGImageSourceGetType(source) != nil else {
+            throw ImageUtilsError.invalidImage
+        }
+    }
+
+    #if os(iOS)
+    static func processImage(_ image: UIImage, maxDimension: CGFloat = 448, outputDirectory: URL? = nil) throws -> URL {
+        return try autoreleasepool {
+            // Scale the image first
+            let scaled = scaledImage(image, maxDimension: maxDimension)
+
+            // Get CGImage from UIImage - this is the key to stripping metadata
+            guard let cgImage = scaled.cgImage else {
+                throw ImageUtilsError.encodingFailed
+            }
+
+            // Use CGImageDestination to encode without metadata (same as macOS)
+            var quality = compressionQuality
+            guard var jpegData = encodeJPEG(from: cgImage, quality: quality) else {
+                throw ImageUtilsError.encodingFailed
+            }
+
+            // Compress to target size
+            while jpegData.count > targetImageBytes && quality > 0.3 {
+                quality -= 0.1
+                autoreleasepool {
+                    if let next = encodeJPEG(from: cgImage, quality: quality) {
+                        jpegData = next
+                    }
+                }
+            }
+
+            let outputURL = try makeOutputURL(outputDirectory: outputDirectory)
+            try jpegData.write(to: outputURL, options: .atomic)
+            return outputURL
+        }
+    }
+
+    private static func scaledImage(_ image: UIImage, maxDimension: CGFloat) -> UIImage {
+        let size = image.size
+        let maxSide = max(size.width, size.height)
+        guard maxSide > maxDimension else { return image }
+        let scale = maxDimension / maxSide
+        let newSize = CGSize(width: size.width * scale, height: size.height * scale)
+
+        // Draw into a new context to get a clean CGImage without metadata
+        UIGraphicsBeginImageContextWithOptions(newSize, true, 1.0)
+        image.draw(in: CGRect(origin: .zero, size: newSize))
+        let rendered = UIGraphicsGetImageFromCurrentImageContext()
+        UIGraphicsEndImageContext()
+        return rendered ?? image
+    }
+
+    // Shared EXIF-stripping JPEG encoder for both iOS and macOS
+    private static func encodeJPEG(from cgImage: CGImage, quality: CGFloat) -> Data? {
+        guard let data = CFDataCreateMutable(nil, 0) else {
+            return nil
+        }
+        guard let destination = CGImageDestinationCreateWithData(data, UTType.jpeg.identifier as CFString, 1, nil) else {
+            return nil
+        }
+        // Security: Strip ALL metadata (EXIF, GPS, TIFF, IPTC, XMP)
+        // By only specifying compression quality and no metadata keys,
+        // we ensure a clean JPEG with no privacy-leaking information
+        let options: [CFString: Any] = [
+            kCGImageDestinationLossyCompressionQuality: quality
+        ]
+        CGImageDestinationAddImage(destination, cgImage, options as CFDictionary)
+        guard CGImageDestinationFinalize(destination) else {
+            return nil
+        }
+        return data as Data
+    }
+    #else
+    static func processImage(_ image: NSImage, maxDimension: CGFloat = 448, outputDirectory: URL? = nil) throws -> URL {
+        return try autoreleasepool {
+            let scaled = scaledImage(image, maxDimension: maxDimension)
+            guard let inputCG = scaled.cgImage(forProposedRect: nil, context: nil, hints: nil) else {
+                throw ImageUtilsError.encodingFailed
+            }
+            let width = inputCG.width
+            let height = inputCG.height
+            let colorSpace = CGColorSpace(name: CGColorSpace.sRGB) ?? CGColorSpaceCreateDeviceRGB()
+            guard let context = CGContext(
+                data: nil,
+                width: width,
+                height: height,
+                bitsPerComponent: 8,
+                bytesPerRow: 0,
+                space: colorSpace,
+                bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue
+            ) else {
+                throw ImageUtilsError.encodingFailed
+            }
+            context.draw(inputCG, in: CGRect(x: 0, y: 0, width: width, height: height))
+            guard let cgImage = context.makeImage() else {
+                throw ImageUtilsError.encodingFailed
+            }
+            var quality = compressionQuality
+            guard var jpegData = encodeJPEG(from: cgImage, quality: quality) else {
+                throw ImageUtilsError.encodingFailed
+            }
+            while jpegData.count > targetImageBytes && quality > 0.3 {
+                quality -= 0.1
+                autoreleasepool {
+                    if let next = encodeJPEG(from: cgImage, quality: quality) {
+                        jpegData = next
+                    }
+                }
+            }
+            let outputURL = try makeOutputURL(outputDirectory: outputDirectory)
+            try jpegData.write(to: outputURL, options: .atomic)
+            return outputURL
+        }
+    }
+
+    private static func scaledImage(_ image: NSImage, maxDimension: CGFloat) -> NSImage {
+        let size = image.size
+        let maxSide = max(size.width, size.height)
+        guard maxSide > maxDimension else { return image }
+        let scale = maxDimension / maxSide
+        let newSize = NSSize(width: size.width * scale, height: size.height * scale)
+        let scaledImage = NSImage(size: newSize)
+        scaledImage.lockFocus()
+        image.draw(in: NSRect(origin: .zero, size: newSize),
+                   from: NSRect(origin: .zero, size: size),
+                   operation: .copy,
+                   fraction: 1.0)
+        scaledImage.unlockFocus()
+        return scaledImage
+    }
+
+    // Shared EXIF-stripping JPEG encoder for both iOS and macOS
+    private static func encodeJPEG(from cgImage: CGImage, quality: CGFloat) -> Data? {
+        guard let data = CFDataCreateMutable(nil, 0) else {
+            return nil
+        }
+        guard let destination = CGImageDestinationCreateWithData(data, UTType.jpeg.identifier as CFString, 1, nil) else {
+            return nil
+        }
+        // Security: Strip ALL metadata (EXIF, GPS, TIFF, IPTC, XMP)
+        // By only specifying compression quality and no metadata keys,
+        // we ensure a clean JPEG with no privacy-leaking information
+        let options: [CFString: Any] = [
+            kCGImageDestinationLossyCompressionQuality: quality
+        ]
+        CGImageDestinationAddImage(destination, cgImage, options as CFDictionary)
+        guard CGImageDestinationFinalize(destination) else {
+            return nil
+        }
+        return data as Data
+    }
+    #endif
+
+    private static func makeOutputURL(outputDirectory: URL? = nil) throws -> URL {
+        let formatter = DateFormatter()
+        formatter.dateFormat = "yyyyMMdd_HHmmss"
+        let fileName = "img_\(formatter.string(from: Date()))_\(UUID().uuidString).jpg"
+
+        let directory: URL
+        if let outputDirectory {
+            directory = outputDirectory
+        } else {
+            directory = try applicationFilesDirectory().appendingPathComponent("images/outgoing", isDirectory: true)
+        }
+        try FileManager.default.createDirectory(at: directory, withIntermediateDirectories: true, attributes: nil)
+        return directory.appendingPathComponent(fileName)
+    }
+
+    private static func applicationFilesDirectory() throws -> URL {
+        let base = try FileManager.default.url(for: .applicationSupportDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
+        return base.appendingPathComponent("files", isDirectory: true)
+    }
+}

bitchat/Features/voice/VoiceNotePlaybackController.swift

@@ -0,0 +1,205 @@
+import Foundation
+import AVFoundation
+import BitLogger
+
+/// Controls playback for a single voice note and coordinates exclusive playback across the app.
+final class VoiceNotePlaybackController: NSObject, ObservableObject, AVAudioPlayerDelegate {
+    @Published private(set) var isPlaying: Bool = false
+    @Published private(set) var currentTime: TimeInterval = 0
+    @Published private(set) var duration: TimeInterval = 0
+    @Published private(set) var progress: Double = 0
+
+    /// rounded so 4.9s shows "00:05"
+    var roundedDuration: Int {
+        guard duration.isFinite else { return 0 }
+        return Int(duration.rounded())
+    }
+
+    /// ceil so "00:01" stays visible until playback ends, capped to rounded duration
+    var remainingSeconds: Int {
+        let remaining = max(0, duration - currentTime)
+        return min(roundedDuration, Int(ceil(remaining)))
+    }
+
+    private var player: AVAudioPlayer?
+    private var timer: Timer?
+    private var url: URL
+
+    init(url: URL) {
+        self.url = url
+        super.init()
+        // Don't load anything eagerly - wait until user interaction or view is fully displayed
+    }
+
+    func loadDuration() {
+        guard duration == 0 else { return }
+
+        DispatchQueue.global(qos: .utility).async { [weak self] in
+            guard let self = self else { return }
+            do {
+                let player = try AVAudioPlayer(contentsOf: self.url)
+                let loadedDuration = player.duration
+                DispatchQueue.main.async { [weak self] in
+                    guard let self = self, self.duration == 0 else { return }
+                    self.duration = loadedDuration
+                }
+            } catch {
+                SecureLogger.error("Failed to load audio duration: \(error)", category: .session)
+            }
+        }
+    }
+
+    deinit {
+        timer?.invalidate()
+    }
+
+    func replaceURL(_ url: URL) {
+        guard url != self.url else { return }
+        stop()
+        self.url = url
+        player = nil
+        duration = 0
+        // Duration will be loaded on demand when needed
+    }
+
+    func togglePlayback() {
+        isPlaying ? pause() : play()
+    }
+
+    func play() {
+        guard ensurePlayerReady() else { return }
+        VoiceNotePlaybackCoordinator.shared.activate(self)
+        player?.play()
+        startTimer()
+        updateProgress()
+        isPlaying = true
+    }
+
+    func pause() {
+        player?.pause()
+        stopTimer()
+        updateProgress()
+        isPlaying = false
+    }
+
+    func stop() {
+        player?.stop()
+        player?.currentTime = 0
+        stopTimer()
+        updateProgress()
+        isPlaying = false
+        VoiceNotePlaybackCoordinator.shared.deactivate(self)
+    }
+
+    func seek(to fraction: Double) {
+        guard ensurePlayerReady() else { return }
+        let clamped = max(0, min(1, fraction))
+        if let player = player {
+            player.currentTime = clamped * player.duration
+            if isPlaying {
+                player.play()
+            }
+            updateProgress()
+        }
+    }
+
+    // MARK: - AVAudioPlayerDelegate
+
+    func audioPlayerDidFinishPlaying(_ player: AVAudioPlayer, successfully flag: Bool) {
+        // Delegate callback may be on background thread - ensure main thread for UI updates
+        DispatchQueue.main.async { [weak self] in
+            guard let self = self else { return }
+            self.stopTimer()
+            self.updateProgress()
+            self.isPlaying = false
+            VoiceNotePlaybackCoordinator.shared.deactivate(self)
+        }
+    }
+
+    // MARK: - Private Helpers
+
+    private func preparePlayer(for url: URL) {
+        // Prepare player synchronously (only called when playback is requested)
+        do {
+            let player = try AVAudioPlayer(contentsOf: url)
+            player.delegate = self
+            player.prepareToPlay()
+            self.player = player
+            duration = player.duration
+            currentTime = player.currentTime
+            progress = duration > 0 ? currentTime / duration : 0
+        } catch {
+            SecureLogger.error("Voice note playback failed for \(url.lastPathComponent): \(error)", category: .session)
+            player = nil
+            duration = 0
+            currentTime = 0
+            progress = 0
+        }
+    }
+
+    private func ensurePlayerReady() -> Bool {
+        if player == nil {
+            preparePlayer(for: url)
+        }
+        #if os(iOS)
+        let session = AVAudioSession.sharedInstance()
+        do {
+            try session.setCategory(.playback, mode: .spokenAudio, options: [.mixWithOthers])
+            try session.setActive(true, options: [])
+        } catch {
+            SecureLogger.error("Failed to activate audio session: \(error)", category: .session)
+        }
+        #endif
+        return player != nil
+    }
+
+    private func startTimer() {
+        if timer != nil { return }
+        timer = Timer.scheduledTimer(withTimeInterval: 0.05, repeats: true) { [weak self] _ in
+            self?.updateProgress()
+        }
+        if let timer = timer {
+            RunLoop.main.add(timer, forMode: .common)
+        }
+    }
+
+    private func stopTimer() {
+        timer?.invalidate()
+        timer = nil
+    }
+
+    private func updateProgress() {
+        guard let player = player else {
+            currentTime = 0
+            duration = 0
+            progress = 0
+            return
+        }
+        currentTime = player.currentTime
+        duration = player.duration
+        progress = duration > 0 ? currentTime / duration : 0
+    }
+}
+
+/// Ensures only one voice note plays at a time.
+final class VoiceNotePlaybackCoordinator {
+    static let shared = VoiceNotePlaybackCoordinator()
+
+    private weak var activeController: VoiceNotePlaybackController?
+
+    private init() {}
+
+    func activate(_ controller: VoiceNotePlaybackController) {
+        if activeController === controller {
+            return
+        }
+        activeController?.pause()
+        activeController = controller
+    }
+
+    func deactivate(_ controller: VoiceNotePlaybackController) {
+        if activeController === controller {
+            activeController = nil
+        }
+    }
+}

bitchat/Features/voice/VoiceRecorder.swift

@@ -0,0 +1,155 @@
+import Foundation
+import AVFoundation
+
+/// Manages audio capture for mesh voice notes with predictable encoding settings.
+actor VoiceRecorder {
+    enum RecorderError: Error {
+        case microphoneAccessDenied
+        case recorderInitializationFailed
+        case recordingInProgress
+    }
+
+    static let shared = VoiceRecorder()
+
+    private let paddingInterval: TimeInterval = 0.5
+    private let maxRecordingDuration: TimeInterval = 120
+    static let minRecordingDuration: TimeInterval = 1
+
+    private var recorder: AVAudioRecorder?
+    private var currentURL: URL?
+
+    // MARK: - Permissions
+
+    nonisolated
+    func requestPermission() async -> Bool {
+        #if os(iOS)
+        return await withCheckedContinuation { continuation in
+            AVAudioSession.sharedInstance().requestRecordPermission { granted in
+                continuation.resume(returning: granted)
+            }
+        }
+        #elseif os(macOS)
+        return await withCheckedContinuation { continuation in
+            AVCaptureDevice.requestAccess(for: .audio) { granted in
+                continuation.resume(returning: granted)
+            }
+        }
+        #else
+        return true
+        #endif
+    }
+
+    // MARK: - Recording Lifecycle
+
+    @discardableResult
+    func startRecording() throws -> URL {
+        if recorder?.isRecording == true {
+            throw RecorderError.recordingInProgress
+        }
+
+        #if os(iOS)
+        let session = AVAudioSession.sharedInstance()
+        guard session.recordPermission == .granted else {
+            throw RecorderError.microphoneAccessDenied
+        }
+        #if targetEnvironment(simulator)
+        // allowBluetoothHFP is not available on iOS Simulator
+        try session.setCategory(
+            .playAndRecord,
+            mode: .default,
+            options: [.defaultToSpeaker, .allowBluetoothA2DP]
+        )
+        #else
+        try session.setCategory(
+            .playAndRecord,
+            mode: .default,
+            options: [.defaultToSpeaker, .allowBluetoothA2DP, .allowBluetoothHFP]
+        )
+        #endif
+        try session.setActive(true, options: .notifyOthersOnDeactivation)
+        #endif
+        #if os(macOS)
+        guard AVCaptureDevice.authorizationStatus(for: .audio) == .authorized else {
+            throw RecorderError.microphoneAccessDenied
+        }
+        #endif
+
+        let outputURL = try makeOutputURL()
+        let settings: [String: Any] = [
+            AVFormatIDKey: kAudioFormatMPEG4AAC,
+            AVSampleRateKey: 16_000,
+            AVNumberOfChannelsKey: 1,
+            AVEncoderBitRateKey: 16_000
+        ]
+
+        let audioRecorder = try AVAudioRecorder(url: outputURL, settings: settings)
+        audioRecorder.isMeteringEnabled = true
+        audioRecorder.prepareToRecord()
+        audioRecorder.record(forDuration: maxRecordingDuration)
+
+        recorder = audioRecorder
+        currentURL = outputURL
+        return outputURL
+    }
+
+    func stopRecording() async -> URL? {
+        guard let recorder, recorder.isRecording else {
+            return currentURL
+        }
+
+        let sessionURL = currentURL
+
+        try? await Task.sleep(nanoseconds: UInt64(paddingInterval * 1_000_000_000))
+
+        recorder.stop()
+
+        // A new session may have started during the sleep — don't touch its state
+        if self.recorder === recorder {
+            cleanupSession()
+            self.recorder = nil
+            currentURL = nil
+        }
+
+        return sessionURL
+    }
+
+    func cancelRecording() {
+        if let recorder, recorder.isRecording {
+            recorder.stop()
+        }
+        cleanupSession()
+        if let currentURL {
+            try? FileManager.default.removeItem(at: currentURL)
+        }
+        recorder = nil
+        currentURL = nil
+    }
+
+    // MARK: - Helpers
+
+    private func makeOutputURL() throws -> URL {
+        let formatter = DateFormatter()
+        formatter.dateFormat = "yyyyMMdd_HHmmss"
+        let fileName = "voice_\(formatter.string(from: Date())).m4a"
+
+        let baseDirectory = try applicationFilesDirectory().appendingPathComponent("voicenotes/outgoing", isDirectory: true)
+        try FileManager.default.createDirectory(at: baseDirectory, withIntermediateDirectories: true, attributes: nil)
+        return baseDirectory.appendingPathComponent(fileName)
+    }
+
+    private func applicationFilesDirectory() throws -> URL {
+        #if os(iOS)
+        return try FileManager.default.url(for: .applicationSupportDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
+            .appendingPathComponent("files", isDirectory: true)
+        #else
+        let base = try FileManager.default.url(for: .applicationSupportDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
+        return base.appendingPathComponent("files", isDirectory: true)
+        #endif
+    }
+
+    private func cleanupSession() {
+        #if os(iOS)
+        try? AVAudioSession.sharedInstance().setActive(false, options: .notifyOthersOnDeactivation)
+        #endif
+    }
+}

bitchat/Features/voice/Waveform.swift

@@ -0,0 +1,113 @@
+import AVFoundation
+import Foundation
+import BitLogger
+
+/// Generates and caches downsampled waveforms for audio files so UI rendering is cheap.
+final class WaveformCache {
+    static let shared = WaveformCache()
+
+    private let queue = DispatchQueue(label: "com.bitchat.waveform-cache", attributes: .concurrent)
+    private var cache: [URL: (waveform: [Float], lastAccess: Date)] = [:]
+    private let maxCacheSize = 20  // Limit cache to prevent unbounded memory growth
+
+    private init() {}
+
+    func cachedWaveform(for url: URL) -> [Float]? {
+        queue.sync {
+            guard let entry = cache[url] else { return nil }
+            return entry.waveform
+        }
+    }
+
+    func waveform(for url: URL, bins: Int = 120, completion: @escaping ([Float]) -> Void) {
+        queue.async { [weak self] in
+            guard let self = self else { return }
+
+            // Check cache (read-only, no update needed on cache hit for performance)
+            if let entry = self.cache[url] {
+                DispatchQueue.main.async { completion(entry.waveform) }
+                return
+            }
+
+            guard let computed = self.computeWaveform(url: url, bins: bins) else {
+                DispatchQueue.main.async { completion([]) }
+                return
+            }
+
+            self.queue.async(flags: .barrier) { [weak self] in
+                guard let self = self else { return }
+
+                // Evict oldest entry if cache is full
+                if self.cache.count >= self.maxCacheSize {
+                    if let oldest = self.cache.min(by: { $0.value.lastAccess < $1.value.lastAccess }) {
+                        self.cache.removeValue(forKey: oldest.key)
+                    }
+                }
+
+                self.cache[url] = (computed, Date())
+            }
+            DispatchQueue.main.async { completion(computed) }
+        }
+    }
+
+    func purge(url: URL) {
+        queue.async(flags: .barrier) { [weak self] in
+            self?.cache.removeValue(forKey: url)
+        }
+    }
+
+    func purgeAll() {
+        queue.async(flags: .barrier) { [weak self] in
+            self?.cache.removeAll()
+        }
+    }
+
+    private func computeWaveform(url: URL, bins: Int) -> [Float]? {
+        guard bins > 0 else { return nil }
+        // Use autoreleasepool to manage memory from audio buffer allocations
+        return autoreleasepool {
+            do {
+                let audioFile = try AVAudioFile(forReading: url)
+                let length = Int(audioFile.length)
+                guard length > 0 else { return nil }
+
+                guard let buffer = AVAudioPCMBuffer(pcmFormat: audioFile.processingFormat, frameCapacity: AVAudioFrameCount(length)) else {
+                    return nil
+                }
+                try audioFile.read(into: buffer, frameCount: AVAudioFrameCount(length))
+                guard let channelData = buffer.floatChannelData else { return nil }
+
+                let channelCount = Int(audioFile.processingFormat.channelCount)
+                let frameLength = Int(buffer.frameLength)
+                let samplesPerBin = max(1, frameLength / bins)
+
+                var magnitudes: [Float] = Array(repeating: 0, count: bins)
+                for bin in 0..<bins {
+                    let start = bin * samplesPerBin
+                    let end = min(frameLength, start + samplesPerBin)
+                    if start >= end { break }
+
+                    var sum: Float = 0
+                    var sampleCount = 0
+                    for frame in start..<end {
+                        var sampleValue: Float = 0
+                        for channel in 0..<channelCount {
+                            sampleValue += fabsf(channelData[channel][frame])
+                        }
+                        sum += sampleValue / Float(channelCount)
+                        sampleCount += 1
+                    }
+                    magnitudes[bin] = sampleCount > 0 ? sum / Float(sampleCount) : 0
+                }
+
+                if let maxMagnitude = magnitudes.max(), maxMagnitude > 0 {
+                    magnitudes = magnitudes.map { min($0 / maxMagnitude, 1.0) }
+                }
+                return magnitudes
+            } catch {
+                SecureLogger.error("Waveform extraction failed for \(url.lastPathComponent): \(error)", category: .session)
+                return nil
+            }
+        }
+    }
+}

bitchat/Identity/IdentityModels.swift

@@ -81,13 +81,14 @@
 ///
 
 import Foundation
+import BitFoundation
 
 // MARK: - Three-Layer Identity Model
 
 /// Represents the ephemeral layer of identity - short-lived peer IDs that provide network privacy.
 /// These IDs rotate periodically to prevent tracking while maintaining cryptographic relationships.
 struct EphemeralIdentity {
-    let peerID: String          // 8 random bytes
+    let peerID: PeerID          // 8 random bytes
     let sessionStart: Date
     var handshakeState: HandshakeState
 }
@@ -106,6 +107,8 @@ enum HandshakeState {
 struct CryptographicIdentity: Codable {
     let fingerprint: String     // SHA256 of public key
     let publicKey: Data         // Noise static public key
+    // Optional Ed25519 signing public key (used to authenticate public messages)
+    var signingPublicKey: Data? = nil
     let firstSeen: Date
     let lastHandshake: Date?
 }
@@ -123,11 +126,35 @@ struct SocialIdentity: Codable {
     var notes: String?
 }
 
+/// Trust ladder: unknown → casual → vouched → trusted → verified.
+///
+/// Persistence compatibility: `TrustLevel` is stored by its *String* raw
+/// value ("unknown", "casual", …), not by ordinal position, so inserting
+/// `vouched` mid-ladder cannot corrupt previously persisted values — every
+/// pre-existing case keeps the exact raw value it was written with. The
+/// `vouched` tier is additionally never persisted into `SocialIdentity`
+/// (it's recomputed on read from stored vouches), so downgraded builds never
+/// encounter the unfamiliar raw value.
 enum TrustLevel: String, Codable {
-    case unknown = "unknown"
-    case casual = "casual"
-    case trusted = "trusted"
-    case verified = "verified"
+    case unknown
+    case casual
+    /// Transitively trusted: vouched for by at least one peer *I* verified.
+    /// Derived at read time — never written to persistent storage.
+    case vouched
+    case trusted
+    case verified
+}
+
+// MARK: - Vouching (transitive verification)
+
+/// One accepted vouch: a peer I verified (the voucher) attested that they
+/// verified the vouchee. Validity is recomputed on read — a record only
+/// counts while its voucher remains in `verifiedFingerprints` and its
+/// timestamp is within `VouchAttestation.maxAge` — so unverifying a voucher
+/// silently invalidates the vouches they gave without a cascade delete.
+struct VouchRecord: Codable, Equatable {
+    let voucherFingerprint: String
+    let timestamp: Date
 }
 
 // MARK: - Identity Cache
@@ -149,77 +176,29 @@ struct IdentityCache: Codable {
     // Last interaction timestamps (privacy: optional)
     var lastInteractions: [String: Date] = [:] 
     
+    // Blocked Nostr pubkeys (lowercased hex) for geohash chats
+    var blockedNostrPubkeys: Set<String> = []
+
+    // Vouching (transitive verification). All three fields are Optional so
+    // caches persisted before this feature decode cleanly — the synthesized
+    // decoder uses decodeIfPresent for optionals, and a missing key must not
+    // trip the "unreadable cache" recovery path that discards everything.
+
+    // Vouchee fingerprint -> accepted vouches (capped per vouchee)
+    var vouchesByVouchee: [String: [VouchRecord]]? = nil
+
+    // Peer fingerprint -> when we last sent them a vouch batch (rate limit)
+    var vouchBatchSentAt: [String: Date]? = nil
+
+    // Fingerprint -> when we verified it (orders outgoing vouch batches;
+    // entries verified before this field exists sort as oldest)
+    var verifiedAt: [String: Date]? = nil
+
     // Schema version for future migrations
     var version: Int = 1
 }
 
-// MARK: - Identity Resolution
-
-enum IdentityHint {
-    case unknown
-    case likelyKnown(fingerprint: String)
-    case ambiguous(candidates: Set<String>)
-    case verified(fingerprint: String)
-}
-
-// MARK: - Pending Actions
-
-struct PendingActions {
-    var toggleFavorite: Bool?
-    var setTrustLevel: TrustLevel?
-    var setPetname: String?
-}
-
-// MARK: - Privacy Settings
-
-struct PrivacySettings: Codable {
-    // Level 1: Maximum privacy (default)
-    var persistIdentityCache = false
-    var showLastSeen = false
-    
-    // Level 2: Convenience
-    var autoAcceptKnownFingerprints = false
-    var rememberNicknameHistory = false
-    
-    // Level 3: Social
-    var shareTrustNetworkHints = false  // "3 mutual contacts trust this person"
-}
-
-// MARK: - Conflict Resolution
-
-/// Strategies for resolving identity conflicts in the decentralized network.
-/// Handles cases where multiple peers claim the same nickname or when
-/// identity mappings become ambiguous due to network partitions.
-enum ConflictResolution {
-    case acceptNew(petname: String)      // "John (2)"
-    case rejectNew
-    case blockFingerprint(String)
-    case alertUser(message: String)
-}
-
-// MARK: - UI State
-
-struct PeerUIState {
-    let peerID: String
-    let nickname: String
-    var identityState: IdentityState
-    var connectionQuality: ConnectionQuality
-    
-    enum IdentityState {
-        case unknown                    // Gray - No identity info
-        case unverifiedKnown(String)   // Blue - Handshake done, matches cache
-        case verified(String)          // Green - Cryptographically verified
-        case conflict(String, String)  // Red - Nickname doesn't match fingerprint
-        case pending                   // Yellow - Handshake in progress
-    }
-}
-
-enum ConnectionQuality {
-    case excellent
-    case good
-    case poor
-    case disconnected
-}
+//
 
 // MARK: - Migration Support
-// Removed LegacyFavorite - no longer needed
+//

bitchat/Identity/SecureIdentityStateManager.swift

@@ -90,65 +90,149 @@
 /// - Advanced conflict resolution
 ///
 
+import BitLogger
+import BitFoundation
 import Foundation
 import CryptoKit
 
+protocol SecureIdentityStateManagerProtocol {
+    // MARK: Secure Loading/Saving
+    func forceSave()
+    
+    // MARK: Social Identity Management
+    func getSocialIdentity(for fingerprint: String) -> SocialIdentity?
+    
+    // MARK: Cryptographic Identities
+    func upsertCryptographicIdentity(fingerprint: String, noisePublicKey: Data, signingPublicKey: Data?, claimedNickname: String?)
+    func getCryptoIdentitiesByPeerIDPrefix(_ peerID: PeerID) -> [CryptographicIdentity]
+    func updateSocialIdentity(_ identity: SocialIdentity)
+    
+    // MARK: Favorites Management
+    func getFavorites() -> Set<String>
+    func setFavorite(_ fingerprint: String, isFavorite: Bool)
+    func isFavorite(fingerprint: String) -> Bool
+    
+    // MARK: Blocked Users Management
+    func isBlocked(fingerprint: String) -> Bool
+    func setBlocked(_ fingerprint: String, isBlocked: Bool)
+    
+    // MARK: Geohash (Nostr) Blocking
+    func isNostrBlocked(pubkeyHexLowercased: String) -> Bool
+    func setNostrBlocked(_ pubkeyHexLowercased: String, isBlocked: Bool)
+    func getBlockedNostrPubkeys() -> Set<String>
+    
+    // MARK: Ephemeral Session Management
+    func registerEphemeralSession(peerID: PeerID, handshakeState: HandshakeState)
+    func updateHandshakeState(peerID: PeerID, state: HandshakeState)
+    
+    // MARK: Cleanup
+    func clearAllIdentityData()
+    func removeEphemeralSession(peerID: PeerID)
+    
+    // MARK: Verification
+    func setVerified(fingerprint: String, verified: Bool)
+    func isVerified(fingerprint: String) -> Bool
+    func getVerifiedFingerprints() -> Set<String>
+
+    // MARK: Vouching (transitive verification)
+    @discardableResult
+    func recordVouch(voucheeFingerprint: String, voucherFingerprint: String, timestamp: Date) -> Bool
+    func validVouchers(for fingerprint: String) -> [VouchRecord]
+    func isVouched(fingerprint: String) -> Bool
+    func effectiveTrustLevel(for fingerprint: String) -> TrustLevel
+    func lastVouchBatchSent(to fingerprint: String) -> Date?
+    func markVouchBatchSent(to fingerprint: String, at date: Date)
+    func signingPublicKey(forFingerprint fingerprint: String) -> Data?
+    func mostRecentlyVerifiedFingerprints(limit: Int, excluding fingerprint: String) -> [String]
+}
+
 /// Singleton manager for secure identity state persistence and retrieval.
 /// Provides thread-safe access to identity mappings with encryption at rest.
 /// All identity data is stored encrypted in the device Keychain for security.
-class SecureIdentityStateManager {
-    static let shared = SecureIdentityStateManager()
-    
-    private let keychain = KeychainManager.shared
+final class SecureIdentityStateManager: SecureIdentityStateManagerProtocol {
+    private let keychain: KeychainManagerProtocol
     private let cacheKey = "bitchat.identityCache.v2"
     private let encryptionKeyName = "identityCacheEncryptionKey"
     
     // In-memory state
-    private var ephemeralSessions: [String: EphemeralIdentity] = [:]
+    private var ephemeralSessions: [PeerID: EphemeralIdentity] = [:]
     private var cryptographicIdentities: [String: CryptographicIdentity] = [:]
     private var cache: IdentityCache = IdentityCache()
     
-    // Pending actions before handshake
-    private var pendingActions: [String: PendingActions] = [:]
-    
     // Thread safety
     private let queue = DispatchQueue(label: "bitchat.identity.state", attributes: .concurrent)
     
-    // Debouncing for keychain saves
-    private var saveTimer: Timer?
-    private let saveDebounceInterval: TimeInterval = 2.0  // Save at most once every 2 seconds
+    // Pending-save coalescing flag. Reads/writes are serialized on `queue`.
+    // Persistence is done with a fire-and-forget `queue.async(.barrier)` rather
+    // than a retained DispatchSourceTimer: a lingering, never-cancelled timer
+    // keeps the dispatch machinery alive and prevents the unit-test process from
+    // exiting. (The original code used Timer.scheduledTimer on a GCD queue with
+    // no run loop, so saves never actually fired.)
     private var pendingSave = false
-    
+
     // Encryption key
     private let encryptionKey: SymmetricKey
+    /// True when `encryptionKey` is a throwaway generated this session because the
+    /// persisted key could not be read (device locked / access denied). In that
+    /// state we must NOT persist (it would overwrite the real cache with data the
+    /// next launch can't decrypt) and must NOT delete the existing cache.
+    private let encryptionKeyIsEphemeral: Bool
     
-    private init() {
-        // Generate or retrieve encryption key from keychain
+    init(_ keychain: KeychainManagerProtocol) {
+        self.keychain = keychain
+
+        // Retrieve (or, only on genuine first run, generate) the cache
+        // encryption key. We MUST distinguish "key doesn't exist yet" from a
+        // transient failure (device locked / access denied): the legacy
+        // getIdentityKey(forKey:) collapses both to nil, and generating+saving a
+        // new key deletes the existing one first — permanently orphaning the
+        // encrypted cache on a launch that merely couldn't read the key.
         let loadedKey: SymmetricKey
-        
-        // Try to load from keychain
-        if let keyData = keychain.getIdentityKey(forKey: encryptionKeyName) {
+        let keyIsEphemeral: Bool
+
+        switch keychain.getIdentityKeyWithResult(forKey: encryptionKeyName) {
+        case .success(let keyData):
             loadedKey = SymmetricKey(data: keyData)
-            SecureLogger.logKeyOperation("load", keyType: "identity cache encryption key", success: true)
-        }
-        // Generate new key if needed
-        else {
-            loadedKey = SymmetricKey(size: .bits256)
-            let keyData = loadedKey.withUnsafeBytes { Data($0) }
-            // Save to keychain
+            keyIsEphemeral = false
+            SecureLogger.logKeyOperation(.load, keyType: "identity cache encryption key", success: true)
+
+        case .itemNotFound:
+            // Genuine first run: generate and persist a new key.
+            let newKey = SymmetricKey(size: .bits256)
+            let keyData = newKey.withUnsafeBytes { Data($0) }
             let saved = keychain.saveIdentityKey(keyData, forKey: encryptionKeyName)
-            SecureLogger.logKeyOperation("generate", keyType: "identity cache encryption key", success: saved)
+            loadedKey = newKey
+            // If even the save failed, treat the key as ephemeral so we don't
+            // later try to persist a cache the next launch can't read.
+            keyIsEphemeral = !saved
+            SecureLogger.logKeyOperation(.generate, keyType: "identity cache encryption key", success: saved)
+
+        case .deviceLocked, .authenticationFailed, .accessDenied, .otherError:
+            // Transient/critical read failure. Do NOT overwrite the persisted
+            // key. Use a session-only ephemeral key; the real key and cache are
+            // left intact for a healthy launch.
+            SecureLogger.warning("Identity cache key unavailable; using ephemeral key for this session (not persisting)", category: .security)
+            loadedKey = SymmetricKey(size: .bits256)
+            keyIsEphemeral = true
         }
-        
+
         self.encryptionKey = loadedKey
-        
-        // Load identity cache on init
-        loadIdentityCache()
+        self.encryptionKeyIsEphemeral = keyIsEphemeral
+
+        // Only read the persisted cache when we hold the real key; with an
+        // ephemeral key the decrypt would fail and discard the real cache.
+        if !keyIsEphemeral {
+            loadIdentityCache()
+        }
+    }
+    
+    deinit {
+        forceSave()
     }
     
     // MARK: - Secure Loading/Saving
     
-    func loadIdentityCache() {
+    private func loadIdentityCache() {
         guard let encryptedData = keychain.getIdentityKey(forKey: cacheKey) else {
             // No existing cache, start fresh
             return
@@ -159,67 +243,57 @@ class SecureIdentityStateManager {
             let decryptedData = try AES.GCM.open(sealedBox, using: encryptionKey)
             cache = try JSONDecoder().decode(IdentityCache.self, from: decryptedData)
         } catch {
-            // Log error but continue with empty cache
-            SecureLogger.logError(error, context: "Failed to load identity cache", category: SecureLogger.security)
+            cache = IdentityCache()
+            let deleted = keychain.deleteIdentityKey(forKey: cacheKey)
+            SecureLogger.warning(
+                "Discarded unreadable identity cache; starting fresh (deleted=\(deleted), error=\(error.localizedDescription))",
+                category: .security
+            )
         }
     }
     
-    deinit {
-        // Force save any pending changes
-        forceSave()
-    }
-    
-    func saveIdentityCache() {
-        // Mark that we need to save
+    /// Persists the cache. Always invoked on `queue` under a barrier (its callers
+    /// run inside `queue.async(.barrier)`), so it simply marks the cache dirty
+    /// and persists it on the same serialized context — no timer, nothing left
+    /// scheduled to keep the process alive.
+    private func saveIdentityCache() {
         pendingSave = true
-        
-        // Cancel any existing timer
-        saveTimer?.invalidate()
-        
-        // Schedule a new save after the debounce interval
-        saveTimer = Timer.scheduledTimer(withTimeInterval: saveDebounceInterval, repeats: false) { [weak self] _ in
-            self?.performSave()
-        }
+        performSave()
     }
-    
+
+    /// Writes the cache to the keychain. Must run on `queue` with exclusive
+    /// (barrier) access.
     private func performSave() {
         guard pendingSave else { return }
         pendingSave = false
-        
+
+        // Never persist under an ephemeral key — it would overwrite the real
+        // cache with data the next launch cannot decrypt.
+        guard !encryptionKeyIsEphemeral else {
+            SecureLogger.debug("Skipping identity cache save (ephemeral key this session)", category: .security)
+            return
+        }
+
         do {
             let data = try JSONEncoder().encode(cache)
             let sealedBox = try AES.GCM.seal(data, using: encryptionKey)
             let saved = keychain.saveIdentityKey(sealedBox.combined!, forKey: cacheKey)
             if saved {
-                SecureLogger.log("Identity cache saved to keychain", category: SecureLogger.security, level: .debug)
+                SecureLogger.debug("Identity cache saved to keychain", category: .security)
             }
         } catch {
-            SecureLogger.logError(error, context: "Failed to save identity cache", category: SecureLogger.security)
+            SecureLogger.error(error, context: "Failed to save identity cache", category: .security)
         }
     }
-    
-    // Force immediate save (for app termination)
+
+    // Force immediate save (for app termination / lifecycle events). Mutations
+    // already persist synchronously via saveIdentityCache, so this is normally a
+    // no-op (performSave early-returns when nothing is pending). Runs directly on
+    // the caller's thread — deliberately NOT a `queue.sync(barrier)`, which is
+    // reachable from `deinit` and from async tests on the swift-concurrency
+    // cooperative pool where a blocking barrier-sync can starve/deadlock it.
     func forceSave() {
-        saveTimer?.invalidate()
-        if pendingSave {
-            performSave()
-        }
-    }
-    
-    // MARK: - Identity Resolution
-    
-    func resolveIdentity(peerID: String, claimedNickname: String) -> IdentityHint {
-        queue.sync {
-            // Check if we have candidates based on nickname
-            if let fingerprints = cache.nicknameIndex[claimedNickname] {
-                if fingerprints.count == 1 {
-                    return .likelyKnown(fingerprint: fingerprints.first!)
-                } else {
-                    return .ambiguous(candidates: fingerprints)
-                }
-            }
-            return .unknown
-        }
+        performSave()
     }
     
     // MARK: - Social Identity Management
@@ -229,25 +303,98 @@ class SecureIdentityStateManager {
             return cache.socialIdentities[fingerprint]
         }
     }
-    
-    func getAllSocialIdentities() -> [SocialIdentity] {
+
+    // MARK: - Cryptographic Identities
+
+    /// Insert or update a cryptographic identity and optionally persist its signing key and claimed nickname.
+    /// - Parameters:
+    ///   - fingerprint: SHA-256 hex of the Noise static public key
+    ///   - noisePublicKey: Noise static public key data
+    ///   - signingPublicKey: Optional Ed25519 signing public key for authenticating public messages
+    ///   - claimedNickname: Optional latest claimed nickname to persist into social identity
+    func upsertCryptographicIdentity(fingerprint: String, noisePublicKey: Data, signingPublicKey: Data?, claimedNickname: String? = nil) {
+        queue.async(flags: .barrier) {
+            let now = Date()
+            if var existing = self.cryptographicIdentities[fingerprint] {
+                // Update keys if changed
+                if existing.publicKey != noisePublicKey {
+                    existing = CryptographicIdentity(
+                        fingerprint: fingerprint,
+                        publicKey: noisePublicKey,
+                        signingPublicKey: signingPublicKey ?? existing.signingPublicKey,
+                        firstSeen: existing.firstSeen,
+                        lastHandshake: now
+                    )
+                    self.cryptographicIdentities[fingerprint] = existing
+                } else {
+                    // Update signing key and lastHandshake
+                    existing.signingPublicKey = signingPublicKey ?? existing.signingPublicKey
+                    let updated = CryptographicIdentity(
+                        fingerprint: existing.fingerprint,
+                        publicKey: existing.publicKey,
+                        signingPublicKey: existing.signingPublicKey,
+                        firstSeen: existing.firstSeen,
+                        lastHandshake: now
+                    )
+                    self.cryptographicIdentities[fingerprint] = updated
+                }
+                // Persist updated state (already assigned in branches above)
+            } else {
+                // New entry
+                let entry = CryptographicIdentity(
+                    fingerprint: fingerprint,
+                    publicKey: noisePublicKey,
+                    signingPublicKey: signingPublicKey,
+                    firstSeen: now,
+                    lastHandshake: now
+                )
+                self.cryptographicIdentities[fingerprint] = entry
+            }
+
+            // Optionally persist claimed nickname into social identity
+            if let claimed = claimedNickname {
+                var identity = self.cache.socialIdentities[fingerprint] ?? SocialIdentity(
+                    fingerprint: fingerprint,
+                    localPetname: nil,
+                    claimedNickname: claimed,
+                    trustLevel: .unknown,
+                    isFavorite: false,
+                    isBlocked: false,
+                    notes: nil
+                )
+                // Update claimed nickname if changed
+                if identity.claimedNickname != claimed {
+                    identity.claimedNickname = claimed
+                    self.cache.socialIdentities[fingerprint] = identity
+                } else if self.cache.socialIdentities[fingerprint] == nil {
+                    self.cache.socialIdentities[fingerprint] = identity
+                }
+            }
+
+            self.saveIdentityCache()
+        }
+    }
+
+    /// Find cryptographic identities whose fingerprint prefix matches a peerID (16-hex) short ID
+    func getCryptoIdentitiesByPeerIDPrefix(_ peerID: PeerID) -> [CryptographicIdentity] {
         queue.sync {
-            return Array(cache.socialIdentities.values)
+            // Defensive: ensure hex and correct length
+            guard peerID.isShort else { return [] }
+            return cryptographicIdentities.values.filter { $0.fingerprint.hasPrefix(peerID.id) }
         }
     }
     
     func updateSocialIdentity(_ identity: SocialIdentity) {
         queue.async(flags: .barrier) {
+            let previousClaimedNickname = self.cache.socialIdentities[identity.fingerprint]?.claimedNickname
             self.cache.socialIdentities[identity.fingerprint] = identity
             
             // Update nickname index
-            if let existingIdentity = self.cache.socialIdentities[identity.fingerprint] {
-                // Remove old nickname from index if changed
-                if existingIdentity.claimedNickname != identity.claimedNickname {
-                    self.cache.nicknameIndex[existingIdentity.claimedNickname]?.remove(identity.fingerprint)
-                    if self.cache.nicknameIndex[existingIdentity.claimedNickname]?.isEmpty == true {
-                        self.cache.nicknameIndex.removeValue(forKey: existingIdentity.claimedNickname)
-                    }
+            if let previousClaimedNickname,
+               previousClaimedNickname != identity.claimedNickname {
+                self.cache.nicknameIndex[previousClaimedNickname]?.remove(identity.fingerprint)
+                if self.cache.nicknameIndex[previousClaimedNickname]?.isEmpty == true {
+                    self.cache.nicknameIndex.removeValue(forKey: previousClaimedNickname)
                 }
             }
             
@@ -310,7 +457,7 @@ class SecureIdentityStateManager {
     }
     
     func setBlocked(_ fingerprint: String, isBlocked: Bool) {
-        SecureLogger.log("User \(isBlocked ? "blocked" : "unblocked"): \(fingerprint)", category: SecureLogger.security, level: .info)
+        SecureLogger.info("User \(isBlocked ? "blocked" : "unblocked"): \(fingerprint)", category: .security)
         
         queue.async(flags: .barrier) {
             if var identity = self.cache.socialIdentities[fingerprint] {
@@ -335,10 +482,34 @@ class SecureIdentityStateManager {
             self.saveIdentityCache()
         }
     }
+
+    // MARK: - Geohash (Nostr) Blocking
+    
+    func isNostrBlocked(pubkeyHexLowercased: String) -> Bool {
+        queue.sync {
+            return cache.blockedNostrPubkeys.contains(pubkeyHexLowercased.lowercased())
+        }
+    }
+    
+    func setNostrBlocked(_ pubkeyHexLowercased: String, isBlocked: Bool) {
+        let key = pubkeyHexLowercased.lowercased()
+        queue.async(flags: .barrier) {
+            if isBlocked {
+                self.cache.blockedNostrPubkeys.insert(key)
+            } else {
+                self.cache.blockedNostrPubkeys.remove(key)
+            }
+            self.saveIdentityCache()
+        }
+    }
+    
+    func getBlockedNostrPubkeys() -> Set<String> {
+        queue.sync { cache.blockedNostrPubkeys }
+    }
     
     // MARK: - Ephemeral Session Management
     
-    func registerEphemeralSession(peerID: String, handshakeState: HandshakeState = .none) {
+    func registerEphemeralSession(peerID: PeerID, handshakeState: HandshakeState = .none) {
         queue.async(flags: .barrier) {
             self.ephemeralSessions[peerID] = EphemeralIdentity(
                 peerID: peerID,
@@ -348,7 +519,7 @@ class SecureIdentityStateManager {
         }
     }
     
-    func updateHandshakeState(peerID: String, state: HandshakeState) {
+    func updateHandshakeState(peerID: PeerID, state: HandshakeState) {
         queue.async(flags: .barrier) {
             self.ephemeralSessions[peerID]?.handshakeState = state
             
@@ -360,95 +531,50 @@ class SecureIdentityStateManager {
         }
     }
     
-    func getHandshakeState(peerID: String) -> HandshakeState? {
-        queue.sync {
-            return ephemeralSessions[peerID]?.handshakeState
-        }
-    }
-    
-    // MARK: - Pending Actions
-    
-    func setPendingAction(peerID: String, action: PendingActions) {
-        queue.async(flags: .barrier) {
-            self.pendingActions[peerID] = action
-        }
-    }
-    
-    func applyPendingActions(peerID: String, fingerprint: String) {
-        queue.async(flags: .barrier) {
-            guard let actions = self.pendingActions[peerID] else { return }
-            
-            // Get or create social identity
-            var identity = self.cache.socialIdentities[fingerprint] ?? SocialIdentity(
-                fingerprint: fingerprint,
-                localPetname: nil,
-                claimedNickname: "Unknown",
-                trustLevel: .unknown,
-                isFavorite: false,
-                isBlocked: false,
-                notes: nil
-            )
-            
-            // Apply pending actions
-            if let toggleFavorite = actions.toggleFavorite {
-                identity.isFavorite = toggleFavorite
-            }
-            if let trustLevel = actions.setTrustLevel {
-                identity.trustLevel = trustLevel
-            }
-            if let petname = actions.setPetname {
-                identity.localPetname = petname
-            }
-            
-            // Save updated identity
-            self.cache.socialIdentities[fingerprint] = identity
-            self.pendingActions.removeValue(forKey: peerID)
-            self.saveIdentityCache()
-        }
-    }
-    
     // MARK: - Cleanup
     
     func clearAllIdentityData() {
-        SecureLogger.log("Clearing all identity data", category: SecureLogger.security, level: .warning)
+        SecureLogger.warning("Clearing all identity data", category: .security)
         
         queue.async(flags: .barrier) {
             self.cache = IdentityCache()
             self.ephemeralSessions.removeAll()
             self.cryptographicIdentities.removeAll()
-            self.pendingActions.removeAll()
             
             // Delete from keychain
             let deleted = self.keychain.deleteIdentityKey(forKey: self.cacheKey)
-            SecureLogger.logKeyOperation("delete", keyType: "identity cache", success: deleted)
+            SecureLogger.logKeyOperation(.delete, keyType: "identity cache", success: deleted)
         }
     }
     
-    func removeEphemeralSession(peerID: String) {
+    func removeEphemeralSession(peerID: PeerID) {
         queue.async(flags: .barrier) {
             self.ephemeralSessions.removeValue(forKey: peerID)
-            self.pendingActions.removeValue(forKey: peerID)
         }
     }
     
     // MARK: - Verification
     
     func setVerified(fingerprint: String, verified: Bool) {
-        SecureLogger.log("Fingerprint \(verified ? "verified" : "unverified"): \(fingerprint)", category: SecureLogger.security, level: .info)
+        SecureLogger.info("Fingerprint \(verified ? "verified" : "unverified"): \(fingerprint)", category: .security)
         
         queue.async(flags: .barrier) {
             if verified {
                 self.cache.verifiedFingerprints.insert(fingerprint)
+                var verifiedAt = self.cache.verifiedAt ?? [:]
+                verifiedAt[fingerprint] = Date()
+                self.cache.verifiedAt = verifiedAt
             } else {
                 self.cache.verifiedFingerprints.remove(fingerprint)
+                self.cache.verifiedAt?.removeValue(forKey: fingerprint)
             }
-            
+
             // Update trust level if social identity exists
             if var identity = self.cache.socialIdentities[fingerprint] {
                 identity.trustLevel = verified ? .verified : .casual
                 self.cache.socialIdentities[fingerprint] = identity
             }
-            
+
             self.saveIdentityCache()
         }
     }
@@ -464,4 +590,169 @@ class SecureIdentityStateManager {
             return cache.verifiedFingerprints
         }
     }
-}
+
+    // MARK: - Vouching (transitive verification)
+
+    /// Maximum vouchers retained per vouchee (most recent kept).
+    static let maxVouchersPerVouchee = 8
+
+    /// Records an accepted vouch, enforcing every accept-policy gate that can
+    /// be evaluated against stored state (signature verification is the
+    /// caller's job — it needs the sender's announce-bound signing key):
+    /// - the voucher must be a fingerprint *I* verified
+    /// - self-vouches are ignored
+    /// - vouches for peers I already verified are ignored (nothing to add)
+    /// - attestations outside the validity window are ignored
+    /// - at most `maxVouchersPerVouchee` vouchers are kept per vouchee
+    ///
+    /// Returns true when the vouch was stored (or refreshed).
+    @discardableResult
+    func recordVouch(voucheeFingerprint: String, voucherFingerprint: String, timestamp: Date) -> Bool {
+        recordVouch(
+            voucheeFingerprint: voucheeFingerprint,
+            voucherFingerprint: voucherFingerprint,
+            timestamp: timestamp,
+            now: Date()
+        )
+    }
+
+    @discardableResult
+    func recordVouch(voucheeFingerprint: String, voucherFingerprint: String, timestamp: Date, now: Date) -> Bool {
+        queue.sync(flags: .barrier) {
+            guard voucheeFingerprint != voucherFingerprint,
+                  self.cache.verifiedFingerprints.contains(voucherFingerprint),
+                  !self.cache.verifiedFingerprints.contains(voucheeFingerprint) else {
+                return false
+            }
+            let age = now.timeIntervalSince(timestamp)
+            guard age <= VouchAttestation.maxAge, age >= -VouchAttestation.maxClockSkew else {
+                return false
+            }
+
+            var records = self.cache.vouchesByVouchee?[voucheeFingerprint] ?? []
+            if let index = records.firstIndex(where: { $0.voucherFingerprint == voucherFingerprint }) {
+                let newest = max(records[index].timestamp, timestamp)
+                records[index] = VouchRecord(voucherFingerprint: voucherFingerprint, timestamp: newest)
+            } else {
+                records.append(VouchRecord(voucherFingerprint: voucherFingerprint, timestamp: timestamp))
+            }
+            // Keep the most recent vouchers up to the cap.
+            records.sort { $0.timestamp > $1.timestamp }
+            let capped = Array(records.prefix(Self.maxVouchersPerVouchee))
+            guard capped.contains(where: { $0.voucherFingerprint == voucherFingerprint }) else {
+                return false // Full of fresher vouches; nothing changed.
+            }
+
+            var vouches = self.cache.vouchesByVouchee ?? [:]
+            vouches[voucheeFingerprint] = capped
+            self.cache.vouchesByVouchee = vouches
+            self.saveIdentityCache()
+            return true
+        }
+    }
+
+    /// The vouches that currently count for `fingerprint`. Validity is
+    /// recomputed here rather than maintained by cascade deletes: a record
+    /// only counts while its voucher is still verified-by-me and its
+    /// timestamp is within the expiry window.
+    func validVouchers(for fingerprint: String) -> [VouchRecord] {
+        validVouchers(for: fingerprint, now: Date())
+    }
+
+    func validVouchers(for fingerprint: String, now: Date) -> [VouchRecord] {
+        queue.sync {
+            self.validVouchersLocked(for: fingerprint, now: now)
+        }
+    }
+
+    /// Requires `queue`.
+    private func validVouchersLocked(for fingerprint: String, now: Date) -> [VouchRecord] {
+        guard let records = cache.vouchesByVouchee?[fingerprint] else { return [] }
+        return records.filter { record in
+            record.voucherFingerprint != fingerprint
+                && cache.verifiedFingerprints.contains(record.voucherFingerprint)
+                && now.timeIntervalSince(record.timestamp) <= VouchAttestation.maxAge
+        }
+    }
+
+    /// True when the peer has at least one valid vouch and no explicit
+    /// verification of ours.
+    func isVouched(fingerprint: String) -> Bool {
+        isVouched(fingerprint: fingerprint, now: Date())
+    }
+
+    func isVouched(fingerprint: String, now: Date) -> Bool {
+        queue.sync {
+            guard !self.cache.verifiedFingerprints.contains(fingerprint) else { return false }
+            return !self.validVouchersLocked(for: fingerprint, now: now).isEmpty
+        }
+    }
+
+    /// The trust level to display: explicit verification wins, then the
+    /// persisted level, with `vouched` layered in (derived, never persisted)
+    /// between `casual` and `trusted`.
+    func effectiveTrustLevel(for fingerprint: String) -> TrustLevel {
+        effectiveTrustLevel(for: fingerprint, now: Date())
+    }
+
+    func effectiveTrustLevel(for fingerprint: String, now: Date) -> TrustLevel {
+        queue.sync {
+            if self.cache.verifiedFingerprints.contains(fingerprint) { return .verified }
+            let stored = self.cache.socialIdentities[fingerprint]?.trustLevel ?? .unknown
+            let vouched = !self.validVouchersLocked(for: fingerprint, now: now).isEmpty
+            switch stored {
+            case .verified, .trusted:
+                return stored
+            case .vouched, .casual, .unknown:
+                if vouched { return .vouched }
+                // `.vouched` should never be persisted; degrade defensively.
+                return stored == .vouched ? .casual : stored
+            }
+        }
+    }
+
+    func lastVouchBatchSent(to fingerprint: String) -> Date? {
+        queue.sync { cache.vouchBatchSentAt?[fingerprint] }
+    }
+
+    func markVouchBatchSent(to fingerprint: String, at date: Date) {
+        queue.async(flags: .barrier) {
+            var sentAt = self.cache.vouchBatchSentAt ?? [:]
+            sentAt[fingerprint] = date
+            self.cache.vouchBatchSentAt = sentAt
+            self.saveIdentityCache()
+        }
+    }
+
+    /// The peer's announce-bound Ed25519 signing key, if seen this session.
+    func signingPublicKey(forFingerprint fingerprint: String) -> Data? {
+        queue.sync { cryptographicIdentities[fingerprint]?.signingPublicKey }
+    }
+
+    /// Verified fingerprints ordered most recently verified first (entries
+    /// without a recorded verification time sort last), excluding the given
+    /// fingerprint. Feeds the outgoing vouch batch.
+    func mostRecentlyVerifiedFingerprints(limit: Int, excluding fingerprint: String) -> [String] {
+        queue.sync {
+            let verifiedAt = cache.verifiedAt ?? [:]
+            let ordered = cache.verifiedFingerprints
+                .filter { $0 != fingerprint }
+                .sorted {
+                    (verifiedAt[$0] ?? .distantPast, $0) > (verifiedAt[$1] ?? .distantPast, $1)
+                }
+            return Array(ordered.prefix(limit))
+        }
+    }
+
+    var debugNicknameIndex: [String: Set<String>] {
+        queue.sync { cache.nicknameIndex }
+    }
+
+    func debugEphemeralSession(for peerID: PeerID) -> EphemeralIdentity? {
+        queue.sync { ephemeralSessions[peerID] }
+    }
+
+    func debugLastInteraction(for fingerprint: String) -> Date? {
+        queue.sync { cache.lastInteractions[fingerprint] }
+    }
+}

bitchat/Info.plist

@@ -2,6 +2,8 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
+	<key>AppGroupID</key>
+	<string>$(APP_GROUP_ID)</string>
 	<key>CFBundleDevelopmentRegion</key>
 	<string>$(DEVELOPMENT_LANGUAGE)</string>
 	<key>CFBundleDisplayName</key>
@@ -31,41 +33,36 @@
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 	<key>LSMinimumSystemVersion</key>
 	<string>$(MACOSX_DEPLOYMENT_TARGET)</string>
+	<key>NSBonjourServices</key>
+	<array>
+		<string>_bitchat-bulk._tcp</string>
+	</array>
 	<key>NSBluetoothAlwaysUsageDescription</key>
 	<string>bitchat uses Bluetooth to create a secure mesh network for chatting with nearby users.</string>
 	<key>NSBluetoothPeripheralUsageDescription</key>
 	<string>bitchat uses Bluetooth to discover and connect with other bitchat users nearby.</string>
+	<key>NSCameraUsageDescription</key>
+	<string>bitchat uses the camera to scan QR codes to verify peers.</string>
+	<key>NSLocalNetworkUsageDescription</key>
+	<string>bitchat uses peer-to-peer Wi-Fi to transfer large photos and voice notes directly between nearby devices.</string>
+	<key>NSLocationWhenInUseUsageDescription</key>
+	<string>bitchat uses your approximate location to compute local geohash channels for optional public chats. Exact GPS is never shared.</string>
+	<key>NSMicrophoneUsageDescription</key>
+	<string>bitchat uses the microphone to record voice notes that relay across the mesh.</string>
+	<key>NSPhotoLibraryUsageDescription</key>
+	<string>bitchat lets you pick images from your photo library to share with nearby peers.</string>
 	<key>UIBackgroundModes</key>
 	<array>
 		<string>bluetooth-central</string>
 		<string>bluetooth-peripheral</string>
-		<string>remote-notification</string>
 	</array>
 	<key>UILaunchStoryboardName</key>
 	<string>LaunchScreen</string>
+	<key>UIRequiresFullScreen</key>
+	<true/>
 	<key>UISupportedInterfaceOrientations</key>
 	<array>
 		<string>UIInterfaceOrientationPortrait</string>
 	</array>
-	<key>UISupportedInterfaceOrientations~ipad</key>
-	<array>
-		<string>UIInterfaceOrientationLandscapeLeft</string>
-		<string>UIInterfaceOrientationLandscapeRight</string>
-		<string>UIInterfaceOrientationPortrait</string>
-		<string>UIInterfaceOrientationPortraitUpsideDown</string>
-	</array>
-	<key>NSAppTransportSecurity</key>
-	<dict>
-		<key>NSAllowsArbitraryLoads</key>
-		<false/>
-		<key>NSAllowsArbitraryLoadsForMedia</key>
-		<false/>
-		<key>NSAllowsArbitraryLoadsInWebContent</key>
-		<false/>
-		<key>NSAllowsLocalNetworking</key>
-		<true/>
-	</dict>
-	<key>NSLocalNetworkUsageDescription</key>
-	<string>bitchat uses local network access to discover and connect with other bitchat users on your network.</string>
 </dict>
 </plist>

bitchat/LaunchScreen.storyboard

@@ -37,4 +37,4 @@
             <point key="canvasLocation" x="53" y="375"/>
         </scene>
     </scenes>
-</document>
+</document>

bitchat/Models/BitchatMessage+Media.swift

@@ -0,0 +1,69 @@
+//
+// BitchatMessage+Media.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import BitFoundation
+import Foundation
+
+extension BitchatMessage {
+    enum Media {
+        case voice(URL)
+        case image(URL)
+
+        var url: URL {
+            switch self {
+            case .voice(let url), .image(let url):
+                return url
+            }
+        }
+    }
+
+    // Cache the directory lookup to avoid repeated FileManager calls during view rendering
+    private struct Cache {
+        let filesDir: URL?
+
+        static let shared = Cache()
+        private init() {
+            do {
+                let base = try FileManager.default.url(for: .applicationSupportDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
+                let filesDir = base.appendingPathComponent("files", isDirectory: true)
+                try FileManager.default.createDirectory(at: filesDir, withIntermediateDirectories: true, attributes: nil)
+                self.filesDir = filesDir
+            } catch {
+                filesDir = nil
+            }
+        }
+    }
+
+    func mediaAttachment(for nickname: String) -> Media? {
+        guard let baseDirectory = Cache.shared.filesDir else { return nil }
+
+        func url(for category: MimeType.Category) -> URL? {
+            guard content.hasPrefix(category.messagePrefix),
+                  let filename = String(content.dropFirst(category.messagePrefix.count)).trimmedOrNilIfEmpty
+            else {
+                return nil
+            }
+
+            // Check outgoing first for sent messages, incoming for received
+            let subdir = sender == nickname ? "\(category.mediaDir)/outgoing" : "\(category.mediaDir)/incoming"
+
+            // Construct URL directly without fileExists check (avoids blocking disk I/O in view body)
+            // Files are checked during playback/display, so missing files fail gracefully
+            let directory = baseDirectory.appendingPathComponent(subdir, isDirectory: true)
+            return directory.appendingPathComponent(filename)
+        }
+
+        if let url = url(for: .audio) {
+            return .voice(url)
+        }
+        if let url = url(for: .image) {
+            return .image(url)
+        }
+        return nil
+    }
+}

bitchat/Models/BitchatPeer.swift

@@ -1,13 +1,15 @@
 import Foundation
 import CoreBluetooth
+import BitFoundation
 
 /// Represents a peer in the BitChat network with all associated metadata
-struct BitchatPeer: Identifiable, Equatable {
-    let id: String // Hex-encoded peer ID
+struct BitchatPeer: Equatable {
+    let peerID: PeerID // Hex-encoded peer ID
     let noisePublicKey: Data
     let nickname: String
     let lastSeen: Date
     let isConnected: Bool
+    let isReachable: Bool
     
     // Favorite-related properties
     var favoriteStatus: FavoritesPersistenceService.FavoriteRelationship?
@@ -18,7 +20,7 @@ struct BitchatPeer: Identifiable, Equatable {
     // Connection state
     enum ConnectionState {
         case bluetoothConnected
-        case relayConnected     // Connected via mesh relay (another peer)
+        case meshReachable      // Seen via mesh recently, not directly connected
         case nostrAvailable     // Mutual favorite, reachable via Nostr
         case offline            // Not connected via any transport
     }
@@ -26,8 +28,8 @@ struct BitchatPeer: Identifiable, Equatable {
     var connectionState: ConnectionState {
         if isConnected {
             return .bluetoothConnected
-        } else if isRelayConnected {
-            return .relayConnected
+        } else if isReachable {
+            return .meshReachable
         } else if favoriteStatus?.isMutual == true {
             // Mutual favorites can communicate via Nostr when offline
             return .nostrAvailable
@@ -36,8 +38,6 @@ struct BitchatPeer: Identifiable, Equatable {
         }
     }
     
-    var isRelayConnected: Bool = false  // Set by PeerManager based on session state
-    
     var isFavorite: Bool {
         favoriteStatus?.isFavorite ?? false
     }
@@ -52,15 +52,15 @@ struct BitchatPeer: Identifiable, Equatable {
     
     // Display helpers
     var displayName: String {
-        nickname.isEmpty ? String(id.prefix(8)) : nickname
+        nickname.isEmpty ? String(peerID.id.prefix(8)) : nickname
     }
     
     var statusIcon: String {
         switch connectionState {
         case .bluetoothConnected:
             return "📻" // Radio icon for mesh connection
-        case .relayConnected:
-            return "🔗" // Chain link for relay connection
+        case .meshReachable:
+            return "📡" // Antenna for mesh reachable
         case .nostrAvailable:
             return "🌐" // Purple globe for Nostr
         case .offline:
@@ -74,19 +74,19 @@ struct BitchatPeer: Identifiable, Equatable {
     
     // Initialize from mesh service data
     init(
-        id: String,
+        peerID: PeerID,
         noisePublicKey: Data,
         nickname: String,
         lastSeen: Date = Date(),
         isConnected: Bool = false,
-        isRelayConnected: Bool = false
+        isReachable: Bool = false
     ) {
-        self.id = id
+        self.peerID = peerID
         self.noisePublicKey = noisePublicKey
         self.nickname = nickname
         self.lastSeen = lastSeen
         self.isConnected = isConnected
-        self.isRelayConnected = isRelayConnected
+        self.isReachable = isReachable
         
         // Load favorite status - will be set later by the manager
         self.favoriteStatus = nil
@@ -94,243 +94,6 @@ struct BitchatPeer: Identifiable, Equatable {
     }
     
     static func == (lhs: BitchatPeer, rhs: BitchatPeer) -> Bool {
-        lhs.id == rhs.id
+        lhs.peerID == rhs.peerID
     }
 }
-
-// MARK: - Peer Manager
-
-/// Manages the collection of peers and their states
-@MainActor
-class PeerManager: ObservableObject {
-    @Published var peers: [BitchatPeer] = []
-    @Published var favorites: [BitchatPeer] = []
-    @Published var mutualFavorites: [BitchatPeer] = []
-    
-    private let meshService: BluetoothMeshService
-    private let favoritesService = FavoritesPersistenceService.shared
-    
-    init(meshService: BluetoothMeshService) {
-        self.meshService = meshService
-        updatePeers()
-        
-        // Listen for updates
-        NotificationCenter.default.addObserver(
-            self,
-            selector: #selector(handleFavoriteChanged),
-            name: .favoriteStatusChanged,
-            object: nil
-        )
-    }
-    
-    @objc private func handleFavoriteChanged() {
-        SecureLogger.log("⭐ Favorite status changed notification received, updating peers", 
-                        category: SecureLogger.session, level: .debug)
-        updatePeers()
-    }
-    
-    deinit {
-        NotificationCenter.default.removeObserver(self)
-    }
-    
-    func updatePeers() {
-        // Reduce log verbosity - only log when count changes
-        let previousCount = peers.count
-        
-        // Get current mesh peers
-        let meshPeers = meshService.getPeerNicknames()
-        
-        // Build peer list
-        var allPeers: [BitchatPeer] = []
-        var connectedNicknames: Set<String> = []
-        
-        // Add connected mesh peers (only if actually connected or relay connected)
-        for (peerID, nickname) in meshPeers {
-            guard let noiseKey = Data(hexString: peerID) else { continue }
-            
-            // Safety check: Never add our own peer ID
-            if peerID == meshService.myPeerID {
-                SecureLogger.log("⚠️ Skipping self peer ID \(peerID) in peer list", 
-                               category: SecureLogger.session, level: .warning)
-                continue
-            }
-            
-            // Check if this peer is actually connected (not just known via relay)
-            let isConnected = meshService.isPeerConnected(peerID)
-            let isKnown = meshService.isPeerKnown(peerID)
-            // In a mesh network, a peer can only be relay-connected if:
-            // 1. We know about them (have received announce)
-            // 2. We're not directly connected
-            // 3. There are other peers that could relay (mesh peer count > 2)
-            // For now, disable relay detection until we have proper relay tracking
-            let isRelayConnected = false
-            
-            // Debug logging for relay connection detection
-            if isKnown && !isConnected {
-                SecureLogger.log("Peer \(nickname) (\(peerID)): isConnected=\(isConnected), isKnown=\(isKnown), isRelayConnected=\(isRelayConnected)", 
-                               category: SecureLogger.session, level: .debug)
-            }
-            
-            // Skip disconnected peers unless they're favorites (handled later)
-            if !isConnected && !isRelayConnected {
-                continue
-            }
-            
-            if isConnected || isRelayConnected {
-                connectedNicknames.insert(nickname)
-            }
-            
-            var peer = BitchatPeer(
-                id: peerID,
-                noisePublicKey: noiseKey,
-                nickname: nickname,
-                isConnected: isConnected,
-                isRelayConnected: isRelayConnected
-            )
-            // Set favorite status - check both by current noise key and by nickname
-            if let favoriteStatus = favoritesService.getFavoriteStatus(for: noiseKey) {
-                peer.favoriteStatus = favoriteStatus
-                peer.nostrPublicKey = favoriteStatus.peerNostrPublicKey
-            } else {
-                // Check if we have a favorite for this nickname (peer may have reconnected with new ID)
-                let favoriteByNickname = favoritesService.favorites.values.first { $0.peerNickname == nickname }
-                if let favorite = favoriteByNickname {
-                    SecureLogger.log("🔄 Found favorite for '\(nickname)' by nickname, updating noise key", 
-                                    category: SecureLogger.session, level: .info)
-                    // Update the favorite's noise key to match the current connection
-                    favoritesService.updateNoisePublicKey(from: favorite.peerNoisePublicKey, to: noiseKey, peerNickname: nickname)
-                    // Get the updated favorite with the new key
-                    peer.favoriteStatus = favoritesService.getFavoriteStatus(for: noiseKey)
-                    peer.nostrPublicKey = peer.favoriteStatus?.peerNostrPublicKey ?? favorite.peerNostrPublicKey
-                }
-            }
-            allPeers.append(peer)
-        }
-        
-        // Add offline favorites (only those not currently connected/relay-connected AND that we actively favorite)
-        SecureLogger.log("📋 Processing \(favoritesService.favorites.count) favorite relationships (connected/relay nicknames: \(connectedNicknames))", 
-                        category: SecureLogger.session, level: .info)
-        
-        for (favoriteKey, favorite) in favoritesService.favorites {
-            let favoriteID = favorite.peerNoisePublicKey.hexEncodedString()
-            
-            // Skip if this peer is already connected or relay-connected (by nickname)
-            if connectedNicknames.contains(favorite.peerNickname) {
-                SecureLogger.log("  - Skipping '\(favorite.peerNickname)' (key: \(favoriteKey.hexEncodedString())) - already connected/relay-connected", 
-                                category: SecureLogger.session, level: .debug)
-                continue
-            }
-            
-            // Only add peers that WE favorite (not just ones who favorite us)
-            if !favorite.isFavorite {
-                SecureLogger.log("  - Skipping '\(favorite.peerNickname)' - we don't favorite them (they favorite us: \(favorite.theyFavoritedUs))", 
-                                category: SecureLogger.session, level: .debug)
-                continue
-            }
-            
-            // Add this favorite as an offline peer
-            SecureLogger.log("  - Adding offline favorite '\(favorite.peerNickname)' (key: \(favoriteKey.hexEncodedString()), ID: \(favoriteID), mutual: \(favorite.isMutual))", 
-                            category: SecureLogger.session, level: .info)
-            
-            var peer = BitchatPeer(
-                id: favoriteID,
-                noisePublicKey: favorite.peerNoisePublicKey,
-                nickname: favorite.peerNickname,
-                isConnected: false
-            )
-            // Set favorite status
-            peer.favoriteStatus = favorite
-            peer.nostrPublicKey = favorite.peerNostrPublicKey
-            allPeers.append(peer)
-        }
-        
-        // Filter out "Unknown" peers unless they are favorites or have a favorite relationship
-        allPeers = allPeers.filter { peer in
-            !(peer.displayName == "Unknown" && peer.favoriteStatus == nil)
-        }
-        
-        // Sort: Connected first (direct then relay), then favorites, then alphabetical
-        allPeers.sort { lhs, rhs in
-            // Direct connections first
-            if lhs.isConnected != rhs.isConnected {
-                return lhs.isConnected
-            }
-            // Then relay connections
-            if lhs.isRelayConnected != rhs.isRelayConnected {
-                return lhs.isRelayConnected
-            }
-            // Then favorites
-            if lhs.isFavorite != rhs.isFavorite {
-                return lhs.isFavorite
-            }
-            // Finally alphabetical
-            return lhs.displayName < rhs.displayName
-        }
-        
-        // Single pass to compute all subsets and counts
-        var favorites: [BitchatPeer] = []
-        var mutualFavorites: [BitchatPeer] = []
-        var connectedCount = 0
-        var offlineCount = 0
-        
-        for peer in allPeers {
-            if peer.isFavorite {
-                favorites.append(peer)
-            }
-            if peer.isMutualFavorite {
-                mutualFavorites.append(peer)
-            }
-            if peer.isConnected {
-                connectedCount += 1
-            } else {
-                offlineCount += 1
-            }
-        }
-        
-        self.peers = allPeers
-        self.favorites = favorites
-        self.mutualFavorites = mutualFavorites
-        
-        // Always log favorites debug info when there are favorites
-        if favoritesService.favorites.count > 0 {
-            SecureLogger.log("📊 Peer list update: \(allPeers.count) total (\(connectedCount) connected, \(offlineCount) offline), \(favorites.count) favorites, \(mutualFavorites.count) mutual", 
-                            category: SecureLogger.session, level: .info)
-            
-            // Log each peer's status
-            for peer in allPeers {
-                // Use the actual statusIcon from the peer which accounts for relay connections
-                let statusIcon: String
-                switch peer.connectionState {
-                case .bluetoothConnected:
-                    statusIcon = "🟢"
-                case .relayConnected:
-                    statusIcon = "🔗"
-                case .nostrAvailable:
-                    statusIcon = "🌐"
-                case .offline:
-                    statusIcon = "🔴"
-                }
-                let favoriteIcon = peer.isMutualFavorite ? "💕" : (peer.isFavorite ? "⭐" : (peer.theyFavoritedUs ? "🌙" : ""))
-                SecureLogger.log("  \(statusIcon) \(peer.displayName) (ID: \(peer.id.prefix(8))...) \(favoriteIcon)", 
-                                category: SecureLogger.session, level: .debug)
-            }
-        } else if previousCount != allPeers.count {
-            // Only log non-favorite updates if count changed
-            SecureLogger.log("✅ Updated peer list: \(allPeers.count) total peers", 
-                            category: SecureLogger.session, level: .info)
-        }
-    }
-    
-    func toggleFavorite(_ peer: BitchatPeer) {
-        if peer.isFavorite {
-            favoritesService.removeFavorite(peerNoisePublicKey: peer.noisePublicKey)
-        } else {
-            favoritesService.addFavorite(
-                peerNoisePublicKey: peer.noisePublicKey,
-                peerNostrPublicKey: peer.nostrPublicKey,
-                peerNickname: peer.nickname
-            )
-        }
-        updatePeers()
-    }
-}

bitchat/Models/CommandInfo.swift

@@ -0,0 +1,84 @@
+//
+// CommandsInfo.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+// MARK: - CommandInfo Enum
+
+enum CommandInfo: String, Identifiable {
+    // Raw values must match the aliases CommandProcessor actually accepts —
+    // the suggestion panel is the app's only command-discovery surface, and
+    // suggesting a spelling the processor rejects teaches users dead ends.
+    case block
+    case clear
+    case group
+    case help
+    case hug
+    case message = "msg"
+    case slap
+    case pay
+    case unblock
+    case who
+    case favorite = "fav"
+    case unfavorite = "unfav"
+    case ping
+    case trace
+
+    var id: String { rawValue }
+
+    var alias: String { "/" + rawValue }
+
+    var placeholder: String? {
+        switch self {
+        case .block, .hug, .message, .slap, .unblock, .favorite, .unfavorite, .ping, .trace:
+            return "<" + String(localized: "content.input.nickname_placeholder") + ">"
+        case .group:
+            return "<" + String(localized: "content.input.group_placeholder") + ">"
+        case .pay:
+            return "<" + String(localized: "content.input.token_placeholder") + ">"
+        case .clear, .help, .who:
+            return nil
+        }
+    }
+
+    var description: String {
+        switch self {
+        case .block:        String(localized: "content.commands.block")
+        case .clear:        String(localized: "content.commands.clear")
+        case .group:        String(localized: "content.commands.group")
+        case .help:         String(localized: "content.commands.help")
+        case .hug:          String(localized: "content.commands.hug")
+        case .message:      String(localized: "content.commands.message")
+        case .pay:          String(localized: "content.commands.pay")
+        case .slap:         String(localized: "content.commands.slap")
+        case .unblock:      String(localized: "content.commands.unblock")
+        case .who:          String(localized: "content.commands.who")
+        case .favorite:     String(localized: "content.commands.favorite")
+        case .unfavorite:   String(localized: "content.commands.unfavorite")
+        case .ping:         String(localized: "content.commands.ping")
+        case .trace:        String(localized: "content.commands.trace")
+        }
+    }
+
+    static func all(isGeoPublic: Bool, isGeoDM: Bool) -> [CommandInfo] {
+        var commands: [CommandInfo] = [.block, .unblock, .clear, .help, .hug, .message, .slap, .who]
+        // Cashu tokens are bearer instruments: in a public geohash any nearby
+        // stranger can redeem one, so don't *suggest* /pay there (the
+        // processor still allows it behind an explicit "public" confirm).
+        // Payments make sense in every DM and in mesh public.
+        if !isGeoPublic {
+            commands.append(.pay)
+        }
+        // The processor rejects favorites, groups and mesh diagnostics in
+        // geohash contexts, so only suggest them where they actually work: mesh.
+        if isGeoPublic || isGeoDM {
+            return commands
+        }
+        return commands + [.favorite, .unfavorite, .group, .ping, .trace]
+    }
+}

bitchat/Models/NoisePayload.swift

@@ -0,0 +1,41 @@
+//
+// NoisePayload.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+/// Helper to create typed Noise payloads
+struct NoisePayload {
+    let type: NoisePayloadType
+    let data: Data
+    
+    /// Encode payload with type prefix
+    func encode() -> Data {
+        var encoded = Data()
+        encoded.append(type.rawValue)
+        encoded.append(data)
+        return encoded
+    }
+    
+    /// Decode payload from data
+    static func decode(_ data: Data) -> NoisePayload? {
+        // Ensure we have at least 1 byte for the type
+        guard !data.isEmpty else {
+            return nil
+        }
+        
+        // Safely get the first byte
+        let firstByte = data[data.startIndex]
+        guard let type = NoisePayloadType(rawValue: firstByte) else {
+            return nil
+        }
+        
+        // Create a proper Data copy (not a subsequence) for thread safety
+        let payloadData = data.count > 1 ? Data(data.dropFirst()) : Data()
+        return NoisePayload(type: type, data: payloadData)
+    }
+}

bitchat/Models/PeerSession.swift

@@ -1,91 +0,0 @@
-import Foundation
-import CoreBluetooth
-
-/// Unified model for tracking all peer session data
-/// Consolidates multiple redundant data structures into a single source of truth
-class PeerSession {
-    // Core identification
-    let peerID: String
-    var nickname: String
-    
-    // Bluetooth connection
-    var peripheral: CBPeripheral?
-    var peripheralID: String?
-    var characteristic: CBCharacteristic?
-    
-    // Authentication and encryption
-    var isAuthenticated: Bool = false
-    var hasEstablishedNoiseSession: Bool = false
-    var fingerprint: String?
-    
-    // Connection state
-    var isConnected: Bool = false
-    var lastSeen: Date
-    
-    // Protocol state
-    var hasAnnounced: Bool = false
-    var hasReceivedAnnounce: Bool = false
-    var isActivePeer: Bool = false
-    
-    // Message tracking
-    var lastMessageSent: Date?
-    var lastMessageReceived: Date?
-    var pendingMessages: [String] = []
-    
-    // Connection timing
-    var lastConnectionTime: Date?
-    var lastSuccessfulMessageTime: Date?
-    var lastHeardFromPeer: Date?
-    
-    // Availability tracking
-    var isAvailable: Bool = false
-    
-    // Identity binding
-    var identityBinding: PeerIdentityBinding?
-    
-    init(peerID: String, nickname: String = "Unknown") {
-        self.peerID = peerID
-        self.nickname = nickname
-        self.lastSeen = Date()
-    }
-    
-    /// Update Bluetooth connection info
-    func updateBluetoothConnection(peripheral: CBPeripheral?, characteristic: CBCharacteristic?) {
-        self.peripheral = peripheral
-        self.peripheralID = peripheral?.identifier.uuidString
-        self.characteristic = characteristic
-        self.isConnected = (peripheral?.state == .connected)
-        if isConnected {
-            self.lastSeen = Date()
-        }
-    }
-    
-    /// Update authentication state
-    func updateAuthenticationState(authenticated: Bool, noiseSession: Bool) {
-        self.isAuthenticated = authenticated
-        self.hasEstablishedNoiseSession = noiseSession
-        if authenticated {
-            self.isActivePeer = true
-        }
-    }
-    
-    
-    /// Check if session is stale
-    var isStale: Bool {
-        // Consider stale if not seen for more than 5 minutes and not connected
-        return !isConnected && Date().timeIntervalSince(lastSeen) > 300
-    }
-    
-    /// Get display status for UI
-    var displayStatus: String {
-        if isConnected {
-            if isAuthenticated {
-                return "🟢" // Connected and authenticated
-            } else {
-                return "🟡" // Connected but not authenticated
-            }
-        } else {
-            return "🔴" // Not connected
-        }
-    }
-}

bitchat/Models/ReadReceipt.swift

@@ -0,0 +1,96 @@
+//
+// ReadReceipt.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+import BitFoundation
+
+struct ReadReceipt: Codable {
+    let originalMessageID: String
+    let receiptID: String
+    var readerID: PeerID  // Who read it
+    let readerNickname: String
+    let timestamp: Date
+    
+    init(originalMessageID: String, readerID: PeerID, readerNickname: String) {
+        self.originalMessageID = originalMessageID
+        self.receiptID = UUID().uuidString
+        self.readerID = readerID
+        self.readerNickname = readerNickname
+        self.timestamp = Date()
+    }
+    
+    // For binary decoding
+    private init(originalMessageID: String, receiptID: String, readerID: PeerID, readerNickname: String, timestamp: Date) {
+        self.originalMessageID = originalMessageID
+        self.receiptID = receiptID
+        self.readerID = readerID
+        self.readerNickname = readerNickname
+        self.timestamp = timestamp
+    }
+    
+    func encode() -> Data? {
+        try? JSONEncoder().encode(self)
+    }
+    
+    static func decode(from data: Data) -> ReadReceipt? {
+        try? JSONDecoder().decode(ReadReceipt.self, from: data)
+    }
+    
+    // MARK: - Binary Encoding
+    
+    func toBinaryData() -> Data {
+        var data = Data()
+        data.appendUUID(originalMessageID)
+        data.appendUUID(receiptID)
+        // ReaderID as 8-byte hex string
+        var readerData = Data()
+        var tempID = readerID.id
+        while tempID.count >= 2 && readerData.count < 8 {
+            let hexByte = String(tempID.prefix(2))
+            if let byte = UInt8(hexByte, radix: 16) {
+                readerData.append(byte)
+            }
+            tempID = String(tempID.dropFirst(2))
+        }
+        while readerData.count < 8 {
+            readerData.append(0)
+        }
+        data.append(readerData)
+        data.appendDate(timestamp)
+        data.appendString(readerNickname)
+        return data
+    }
+    
+    static func fromBinaryData(_ data: Data) -> ReadReceipt? {
+        // Create defensive copy
+        let dataCopy = Data(data)
+        
+        // Minimum size: 2 UUIDs (32) + readerID (8) + timestamp (8) + min nickname
+        guard dataCopy.count >= 49 else { return nil }
+        
+        var offset = 0
+        
+        guard let originalMessageID = dataCopy.readUUID(at: &offset),
+              let receiptID = dataCopy.readUUID(at: &offset) else { return nil }
+        
+        guard let readerIDData = dataCopy.readFixedBytes(at: &offset, count: 8) else { return nil }
+        let readerID = PeerID(hexData: readerIDData)
+        guard readerID.isValid else { return nil }
+        
+        guard let timestamp = dataCopy.readDate(at: &offset),
+              InputValidator.validateTimestamp(timestamp),
+              let readerNicknameRaw = dataCopy.readString(at: &offset),
+              let readerNickname = InputValidator.validateNickname(readerNicknameRaw) else { return nil }
+        
+        return ReadReceipt(originalMessageID: originalMessageID,
+                          receiptID: receiptID,
+                          readerID: readerID,
+                          readerNickname: readerNickname,
+                          timestamp: timestamp)
+    }
+}

bitchat/Models/RequestSyncPacket.swift

@@ -0,0 +1,138 @@
+import BitFoundation
+import Foundation
+
+// REQUEST_SYNC payload TLV (type, length16, value)
+//  - 0x01: P (uint8) — Golomb-Rice parameter
+//  - 0x02: M (uint32, big-endian) — hash range (N * 2^P)
+//  - 0x03: data (opaque) — GR bitstream bytes (MSB-first)
+//  - 0x04: types (SyncTypeFlags) — packet types the filter covers
+//  - 0x05: sinceTimestamp (uint64, big-endian) — filter coverage cursor
+//  - 0x06: fragmentIdFilter (UTF-8) — comma-separated 16-hex-char (8-byte)
+//          fragment stream IDs; restricts the fragment diff to exactly those
+//          streams (targeted resync for stalled reassemblies)
+struct RequestSyncPacket {
+    /// Maximum fragment IDs one 0x06 filter may carry. Each ID encodes as
+    /// 16 hex chars plus a comma separator, so the largest encoded value is
+    /// 60 * 17 - 1 = 1019 bytes, which fits the 1024-byte decoder cap.
+    static let maxFragmentIdFilterCount = 60
+
+    let p: Int
+    let m: UInt32
+    let data: Data
+    let types: SyncTypeFlags?
+    let sinceTimestamp: UInt64?
+    let fragmentIdFilter: String?
+
+    /// Encodes 8-byte fragment stream IDs as the 0x06 filter string,
+    /// dropping malformed IDs and capping at `maxFragmentIdFilterCount`.
+    static func encodeFragmentIdFilter(_ fragmentIDs: [Data]) -> String? {
+        let tokens = fragmentIDs
+            .filter { $0.count == 8 }
+            .prefix(maxFragmentIdFilterCount)
+            .map { $0.hexEncodedString() }
+        guard !tokens.isEmpty else { return nil }
+        return tokens.joined(separator: ",")
+    }
+
+    /// Decodes a 0x06 filter string back into 8-byte fragment stream IDs,
+    /// ignoring malformed tokens and capping at `maxFragmentIdFilterCount`.
+    static func decodeFragmentIdFilter(_ filter: String?) -> Set<Data>? {
+        guard let filter else { return nil }
+        var ids: Set<Data> = []
+        for token in filter.split(separator: ",").prefix(maxFragmentIdFilterCount) {
+            guard token.count == 16, let id = Data(hexString: String(token)) else { continue }
+            ids.insert(id)
+        }
+        return ids.isEmpty ? nil : ids
+    }
+
+    init(p: Int, m: UInt32, data: Data, types: SyncTypeFlags? = nil, sinceTimestamp: UInt64? = nil, fragmentIdFilter: String? = nil) {
+        self.p = p
+        self.m = m
+        self.data = data
+        self.types = types
+        self.sinceTimestamp = sinceTimestamp
+        self.fragmentIdFilter = fragmentIdFilter
+    }
+
+    func encode() -> Data {
+        var out = Data()
+        func putTLV(_ t: UInt8, _ v: Data) {
+            out.append(t)
+            let len = UInt16(v.count)
+            out.append(UInt8((len >> 8) & 0xFF))
+            out.append(UInt8(len & 0xFF))
+            out.append(v)
+        }
+        // P
+        putTLV(0x01, Data([UInt8(p & 0xFF)]))
+        // M (uint32)
+        var mBE = m.bigEndian
+        putTLV(0x02, withUnsafeBytes(of: &mBE) { Data($0) })
+        // data
+        putTLV(0x03, data)
+        if let typesData = types?.toData() {
+            putTLV(0x04, typesData)
+        }
+        if let ts = sinceTimestamp {
+            var tsBE = ts.bigEndian
+            putTLV(0x05, withUnsafeBytes(of: &tsBE) { Data($0) })
+        }
+        if let fid = fragmentIdFilter, let fidData = fid.data(using: .utf8) {
+            putTLV(0x06, fidData)
+        }
+        return out
+    }
+    
+    static func decode(from data: Data, maxAcceptBytes: Int = 1024) -> RequestSyncPacket? {
+        var off = 0
+        var p: Int? = nil
+        var m: UInt32? = nil
+        var payload: Data? = nil
+        var types: SyncTypeFlags? = nil
+        var sinceTimestamp: UInt64? = nil
+        var fragmentIdFilter: String? = nil
+
+        while off + 3 <= data.count {
+            let t = Int(data[off]); off += 1
+            guard off + 2 <= data.count else { return nil }
+            let len = (Int(data[off]) << 8) | Int(data[off+1]); off += 2
+            guard off + len <= data.count else { return nil }
+            let v = data.subdata(in: off..<(off+len)); off += len
+            switch t {
+            case 0x01:
+                if v.count == 1 { p = Int(v[0]) }
+            case 0x02:
+                if v.count == 4 {
+                    var mm: UInt32 = 0
+                    for b in v { mm = (mm << 8) | UInt32(b) }
+                    m = mm
+                }
+            case 0x03:
+                if v.count > maxAcceptBytes { return nil }
+                payload = v
+            case 0x04:
+                if let decoded = SyncTypeFlags.decode(v) {
+                    types = decoded
+                }
+            case 0x05:
+                if v.count == 8 {
+                    var ts: UInt64 = 0
+                    for b in v { ts = (ts << 8) | UInt64(b) }
+                    sinceTimestamp = ts
+                }
+            case 0x06:
+                // Same acceptance cap as the GCS payload; an oversized filter
+                // is ignored rather than failing the whole request.
+                if v.count <= maxAcceptBytes, let fid = String(data: v, encoding: .utf8) {
+                    fragmentIdFilter = fid
+                }
+            default:
+                break // forward compatible; ignore unknown TLVs
+            }
+        }
+
+        guard let pp = p, let mm = m, let dd = payload, pp >= 1, pp <= GCSFilter.maxP, mm > 0 else { return nil }
+        return RequestSyncPacket(p: pp, m: mm, data: dd, types: types, sinceTimestamp: sinceTimestamp, fragmentIdFilter: fragmentIdFilter)
+    }
+}

bitchat/Noise/NoiseHandshakeCoordinator.swift

@@ -1,371 +0,0 @@
-//
-// NoiseHandshakeCoordinator.swift
-// bitchat
-//
-// This is free and unencumbered software released into the public domain.
-// For more information, see <https://unlicense.org>
-//
-
-import Foundation
-
-/// Coordinates Noise handshakes to prevent race conditions and ensure reliable encryption establishment
-class NoiseHandshakeCoordinator {
-    
-    // MARK: - Handshake State
-    
-    enum HandshakeState: Equatable {
-        case idle
-        case waitingToInitiate(since: Date)
-        case initiating(attempt: Int, lastAttempt: Date)
-        case responding(since: Date)
-        case waitingForResponse(messagesSent: [Data], timeout: Date)
-        case established(since: Date)
-        case failed(reason: String, canRetry: Bool, lastAttempt: Date)
-        
-        var isActive: Bool {
-            switch self {
-            case .idle, .established, .failed:
-                return false
-            default:
-                return true
-            }
-        }
-    }
-    
-    // MARK: - Properties
-    
-    private var handshakeStates: [String: HandshakeState] = [:]
-    private var handshakeQueue = DispatchQueue(label: "chat.bitchat.noise.handshake", attributes: .concurrent)
-    
-    // Configuration
-    private let maxHandshakeAttempts = 3
-    private let handshakeTimeout: TimeInterval = 10.0
-    private let retryDelay: TimeInterval = 2.0
-    private let minTimeBetweenHandshakes: TimeInterval = 1.0 // Reduced from 5.0 for faster recovery
-    private let establishedSessionTTL: TimeInterval = 300.0 // 5 minutes - sessions older than this can be cleaned up
-    private let maxEstablishedSessions = 50 // Limit total established sessions
-    
-    // Track handshake messages to detect duplicates
-    private var processedHandshakeMessages: Set<Data> = []
-    private let messageHistoryLimit = 100
-    
-    // MARK: - Role Determination
-    
-    /// Deterministically determine who should initiate the handshake
-    /// Lower peer ID becomes the initiator to prevent simultaneous attempts
-    func determineHandshakeRole(myPeerID: String, remotePeerID: String) -> NoiseRole {
-        // Use simple string comparison for deterministic ordering
-        return myPeerID < remotePeerID ? .initiator : .responder
-    }
-    
-    /// Check if we should initiate handshake with a peer
-    func shouldInitiateHandshake(myPeerID: String, remotePeerID: String, forceIfStale: Bool = false) -> Bool {
-        return handshakeQueue.sync {
-            // Check if we're already in an active handshake
-            if let state = handshakeStates[remotePeerID], state.isActive {
-                // Check if the handshake is stale and we should force a new one
-                if forceIfStale {
-                    switch state {
-                    case .initiating(_, let lastAttempt):
-                        if Date().timeIntervalSince(lastAttempt) > handshakeTimeout {
-                            SecureLogger.log("Forcing new handshake with \(remotePeerID) - previous stuck in initiating", 
-                                           category: SecureLogger.handshake, level: .warning)
-                            return true
-                        }
-                    default:
-                        break
-                    }
-                }
-                
-                SecureLogger.log("Already in active handshake with \(remotePeerID), state: \(state)", 
-                               category: SecureLogger.handshake, level: .debug)
-                return false
-            }
-            
-            // Check role
-            let role = determineHandshakeRole(myPeerID: myPeerID, remotePeerID: remotePeerID)
-            if role != .initiator {
-                SecureLogger.log("Not initiator for handshake with \(remotePeerID) (my: \(myPeerID), their: \(remotePeerID))", 
-                               category: SecureLogger.handshake, level: .debug)
-                return false
-            }
-            
-            // Check if we've failed recently and can't retry yet
-            if case .failed(_, let canRetry, let lastAttempt) = handshakeStates[remotePeerID] {
-                if !canRetry {
-                    return false
-                }
-                if Date().timeIntervalSince(lastAttempt) < retryDelay {
-                    return false
-                }
-            }
-            
-            return true
-        }
-    }
-    
-    /// Record that we're initiating a handshake
-    func recordHandshakeInitiation(peerID: String) {
-        handshakeQueue.async(flags: .barrier) {
-            let attempt = self.getCurrentAttempt(for: peerID) + 1
-            self.handshakeStates[peerID] = .initiating(attempt: attempt, lastAttempt: Date())
-            SecureLogger.log("Recording handshake initiation with \(peerID), attempt \(attempt)", 
-                           category: SecureLogger.handshake, level: .info)
-        }
-    }
-    
-    /// Record that we're responding to a handshake
-    func recordHandshakeResponse(peerID: String) {
-        handshakeQueue.async(flags: .barrier) {
-            self.handshakeStates[peerID] = .responding(since: Date())
-            SecureLogger.log("Recording handshake response to \(peerID)", 
-                           category: SecureLogger.handshake, level: .info)
-        }
-    }
-    
-    /// Record successful handshake completion
-    func recordHandshakeSuccess(peerID: String) {
-        handshakeQueue.async(flags: .barrier) {
-            self.handshakeStates[peerID] = .established(since: Date())
-            SecureLogger.log("Handshake successfully established with \(peerID)", 
-                           category: SecureLogger.handshake, level: .info)
-        }
-    }
-    
-    /// Record handshake failure
-    func recordHandshakeFailure(peerID: String, reason: String) {
-        handshakeQueue.async(flags: .barrier) {
-            let attempts = self.getCurrentAttempt(for: peerID)
-            let canRetry = attempts < self.maxHandshakeAttempts
-            self.handshakeStates[peerID] = .failed(reason: reason, canRetry: canRetry, lastAttempt: Date())
-            SecureLogger.log("Handshake failed with \(peerID): \(reason), canRetry: \(canRetry)", 
-                           category: SecureLogger.handshake, level: .warning)
-        }
-    }
-    
-    /// Check if we should accept an incoming handshake initiation
-    func shouldAcceptHandshakeInitiation(myPeerID: String, remotePeerID: String) -> Bool {
-        return handshakeQueue.sync {
-            // If we're already established, reject new handshakes
-            if case .established = handshakeStates[remotePeerID] {
-                SecureLogger.log("Rejecting handshake from \(remotePeerID) - already established", 
-                               category: SecureLogger.handshake, level: .debug)
-                return false
-            }
-            
-            let role = determineHandshakeRole(myPeerID: myPeerID, remotePeerID: remotePeerID)
-            
-            // If we're the initiator and already initiating, this is a race condition
-            if role == .initiator {
-                if case .initiating = handshakeStates[remotePeerID] {
-                    // They shouldn't be initiating, but accept it to recover from race condition
-                    SecureLogger.log("Accepting handshake from \(remotePeerID) despite being initiator (race condition recovery)", 
-                                   category: SecureLogger.handshake, level: .warning)
-                    return true
-                }
-            }
-            
-            // If we're the responder, we should accept
-            return true
-        }
-    }
-    
-    /// Check if this is a duplicate handshake message
-    func isDuplicateHandshakeMessage(_ data: Data) -> Bool {
-        return handshakeQueue.sync {
-            if processedHandshakeMessages.contains(data) {
-                return true
-            }
-            
-            // Add to processed messages with size limit
-            if processedHandshakeMessages.count >= messageHistoryLimit {
-                processedHandshakeMessages.removeAll()
-            }
-            processedHandshakeMessages.insert(data)
-            return false
-        }
-    }
-    
-    /// Get time to wait before next handshake attempt
-    func getRetryDelay(for peerID: String) -> TimeInterval? {
-        return handshakeQueue.sync {
-            guard let state = handshakeStates[peerID] else { return nil }
-            
-            switch state {
-            case .failed(_, let canRetry, let lastAttempt):
-                if !canRetry { return nil }
-                let timeSinceFailure = Date().timeIntervalSince(lastAttempt)
-                if timeSinceFailure >= retryDelay {
-                    return 0
-                }
-                return retryDelay - timeSinceFailure
-                
-            case .initiating(_, let lastAttempt):
-                let timeSinceAttempt = Date().timeIntervalSince(lastAttempt)
-                if timeSinceAttempt >= minTimeBetweenHandshakes {
-                    return 0
-                }
-                return minTimeBetweenHandshakes - timeSinceAttempt
-                
-            default:
-                return nil
-            }
-        }
-    }
-    
-    /// Reset handshake state for a peer
-    func resetHandshakeState(for peerID: String) {
-        handshakeQueue.async(flags: .barrier) {
-            self.handshakeStates.removeValue(forKey: peerID)
-            SecureLogger.log("Reset handshake state for \(peerID)", 
-                           category: SecureLogger.handshake, level: .debug)
-        }
-    }
-    
-    /// Clean up stale handshake states and old established sessions
-    func cleanupStaleHandshakes(staleTimeout: TimeInterval = 30.0) -> [String] {
-        return handshakeQueue.sync {
-            let now = Date()
-            var stalePeerIDs: [String] = []
-            var establishedSessions: [(peerID: String, since: Date)] = []
-            
-            for (peerID, state) in handshakeStates {
-                var isStale = false
-                
-                switch state {
-                case .initiating(_, let lastAttempt):
-                    if now.timeIntervalSince(lastAttempt) > staleTimeout {
-                        isStale = true
-                    }
-                case .responding(let since):
-                    if now.timeIntervalSince(since) > staleTimeout {
-                        isStale = true
-                    }
-                case .waitingForResponse(_, let timeout):
-                    if now > timeout {
-                        isStale = true
-                    }
-                case .established(let since):
-                    // Track established sessions for potential cleanup
-                    establishedSessions.append((peerID, since))
-                    // Clean up very old established sessions
-                    if now.timeIntervalSince(since) > establishedSessionTTL {
-                        isStale = true
-                    }
-                default:
-                    break
-                }
-                
-                if isStale {
-                    stalePeerIDs.append(peerID)
-                    SecureLogger.log("Found stale handshake state for \(peerID): \(state)", 
-                                   category: SecureLogger.handshake, level: .warning)
-                }
-            }
-            
-            // If we have too many established sessions, clean up the oldest ones
-            if establishedSessions.count > maxEstablishedSessions {
-                // Sort by age (oldest first)
-                let sortedSessions = establishedSessions.sorted { $0.since < $1.since }
-                let sessionsToRemove = sortedSessions.count - maxEstablishedSessions
-                
-                for i in 0..<sessionsToRemove {
-                    let peerID = sortedSessions[i].peerID
-                    stalePeerIDs.append(peerID)
-                    SecureLogger.log("Removing old established session for \(peerID) to maintain session limit", 
-                                   category: SecureLogger.handshake, level: .info)
-                }
-            }
-            
-            // Clean up stale states
-            for peerID in stalePeerIDs {
-                handshakeStates.removeValue(forKey: peerID)
-            }
-            
-            if !stalePeerIDs.isEmpty {
-                SecureLogger.log("Cleaned up \(stalePeerIDs.count) stale handshake states", 
-                               category: SecureLogger.handshake, level: .info)
-            }
-            
-            return stalePeerIDs
-        }
-    }
-    
-    /// Get current handshake state
-    func getHandshakeState(for peerID: String) -> HandshakeState {
-        return handshakeQueue.sync {
-            return handshakeStates[peerID] ?? .idle
-        }
-    }
-    
-    /// Get current retry count for a peer
-    func getRetryCount(for peerID: String) -> Int {
-        return handshakeQueue.sync {
-            switch handshakeStates[peerID] {
-            case .initiating(let attempt, _):
-                return attempt - 1  // Attempts start at 1, retries start at 0
-            default:
-                return 0
-            }
-        }
-    }
-    
-    /// Increment retry count for a peer
-    func incrementRetryCount(for peerID: String) {
-        handshakeQueue.async(flags: .barrier) {
-            let currentAttempt = self.getCurrentAttempt(for: peerID)
-            self.handshakeStates[peerID] = .initiating(attempt: currentAttempt + 1, lastAttempt: Date())
-        }
-    }
-    
-    // MARK: - Private Helpers
-    
-    private func getCurrentAttempt(for peerID: String) -> Int {
-        switch handshakeStates[peerID] {
-        case .initiating(let attempt, _):
-            return attempt
-        case .failed(_, _, _):
-            // Count previous attempts
-            return 1 // Simplified for now
-        default:
-            return 0
-        }
-    }
-    
-    /// Log current handshake states for debugging
-    func logHandshakeStates() {
-        handshakeQueue.sync {
-            SecureLogger.log("=== Handshake States ===", category: SecureLogger.handshake, level: .debug)
-            for (peerID, state) in handshakeStates {
-                let stateDesc: String
-                switch state {
-                case .idle:
-                    stateDesc = "idle"
-                case .waitingToInitiate(let since):
-                    stateDesc = "waiting to initiate (since \(since))"
-                case .initiating(let attempt, let lastAttempt):
-                    stateDesc = "initiating (attempt \(attempt), last: \(lastAttempt))"
-                case .responding(let since):
-                    stateDesc = "responding (since: \(since))"
-                case .waitingForResponse(let messages, let timeout):
-                    stateDesc = "waiting for response (\(messages.count) messages, timeout: \(timeout))"
-                case .established(let since):
-                    stateDesc = "established (since \(since))"
-                case .failed(let reason, let canRetry, let lastAttempt):
-                    stateDesc = "failed: \(reason) (canRetry: \(canRetry), last: \(lastAttempt))"
-                }
-                SecureLogger.log("  \(peerID): \(stateDesc)", category: SecureLogger.handshake, level: .debug)
-            }
-            SecureLogger.log("========================", category: SecureLogger.handshake, level: .debug)
-        }
-    }
-    
-    /// Clear all handshake states - used during panic mode
-    func clearAllHandshakeStates() {
-        handshakeQueue.async(flags: .barrier) {
-            SecureLogger.log("Clearing all handshake states for panic mode", category: SecureLogger.handshake, level: .warning)
-            self.handshakeStates.removeAll()
-            self.processedHandshakeMessages.removeAll()
-        }
-    }
-}

bitchat/Noise/NoiseProtocol.swift

@@ -77,9 +77,10 @@
 /// - Noise Specification: http://www.noiseprotocol.org/noise.html
 ///
 
+import BitLogger
+import BitFoundation
 import Foundation
 import CryptoKit
-import os.log
 
 // Core Noise Protocol implementation
 // Based on the Noise Protocol Framework specification
@@ -92,6 +93,7 @@ enum NoisePattern {
     case XX  // Most versatile, mutual authentication
     case IK  // Initiator knows responder's static key
     case NK  // Anonymous initiator
+    case X   // One-way: single message to a known static key (no response)
 }
 
 enum NoiseRole {
@@ -127,7 +129,7 @@ struct NoiseProtocolName {
 /// Handles ChaCha20-Poly1305 AEAD encryption with automatic nonce management
 /// and replay protection using a sliding window algorithm.
 /// - Warning: Nonce reuse would be catastrophic for security
-class NoiseCipherState {
+final class NoiseCipherState {
     // Constants for replay protection
     private static let NONCE_SIZE_BYTES = 4
     private static let REPLAY_WINDOW_SIZE = 1024
@@ -149,6 +151,10 @@ class NoiseCipherState {
         self.useExtractedNonce = useExtractedNonce
     }
     
+    deinit {
+        clearSensitiveData()
+    }
+    
     func initializeKey(_ key: SymmetricKey) {
         self.key = key
         self.nonce = 0
@@ -161,19 +167,23 @@ class NoiseCipherState {
     // MARK: - Sliding Window Replay Protection
     
     /// Check if nonce is valid for replay protection
+    /// BCH-01-010: Use safe arithmetic to prevent integer overflow
     private func isValidNonce(_ receivedNonce: UInt64) -> Bool {
-        if receivedNonce + UInt64(Self.REPLAY_WINDOW_SIZE) <= highestReceivedNonce {
+        // Safe overflow check: instead of (receivedNonce + WINDOW_SIZE <= highest)
+        // use (highest >= WINDOW_SIZE && receivedNonce <= highest - WINDOW_SIZE)
+        let windowSize = UInt64(Self.REPLAY_WINDOW_SIZE)
+        if highestReceivedNonce >= windowSize && receivedNonce <= highestReceivedNonce - windowSize {
             return false  // Too old, outside window
         }
-        
+
         if receivedNonce > highestReceivedNonce {
             return true  // Always accept newer nonces
         }
-        
+
         let offset = Int(highestReceivedNonce - receivedNonce)
         let byteIndex = offset / 8
         let bitIndex = offset % 8
-        
+
         return (replayWindow[byteIndex] & (1 << bitIndex)) == 0  // Not yet seen
     }
     
@@ -218,7 +228,7 @@ class NoiseCipherState {
         guard combinedPayload.count >= Self.NONCE_SIZE_BYTES else {
             return nil
         }
-
+        
         // Extract 4-byte nonce (big-endian)
         let nonceData = combinedPayload.prefix(Self.NONCE_SIZE_BYTES)
         let extractedNonce = nonceData.withUnsafeBytes { (bytes: UnsafeRawBufferPointer) -> UInt64 in
@@ -229,18 +239,18 @@ class NoiseCipherState {
             }
             return result
         }
-
+        
         // Extract ciphertext (remaining bytes)
         let ciphertext = combinedPayload.dropFirst(Self.NONCE_SIZE_BYTES)
-
+        
         return (nonce: extractedNonce, ciphertext: Data(ciphertext))
     }
-
+    
     /// Convert nonce to 4-byte array (big-endian)
     private func nonceToBytes(_ nonce: UInt64) -> Data {
         var bytes = Data(count: Self.NONCE_SIZE_BYTES)
         withUnsafeBytes(of: nonce.bigEndian) { ptr in
-            // Copy only the last 4 bytes from the 8-byte UInt64 
+            // Copy only the last 4 bytes from the 8-byte UInt64
             let sourceBytes = ptr.bindMemory(to: UInt8.self)
             bytes.replaceSubrange(0..<Self.NONCE_SIZE_BYTES, with: sourceBytes.suffix(Self.NONCE_SIZE_BYTES))
         }
@@ -269,7 +279,7 @@ class NoiseCipherState {
         let sealedBox = try ChaChaPoly.seal(plaintext, using: key, nonce: ChaChaPoly.Nonce(data: nonceData), authenticating: associatedData)
         // increment local nonce
         nonce += 1
-               
+        
         // Create combined payload: <nonce><ciphertext>
         let combinedPayload: Data
         if (useExtractedNonce) {
@@ -281,9 +291,9 @@ class NoiseCipherState {
         
         // Log high nonce values that might indicate issues
         if currentNonce > Self.HIGH_NONCE_WARNING_THRESHOLD {
-            SecureLogger.log("High nonce value detected: \(currentNonce) - consider rekeying", category: SecureLogger.encryption, level: .warning)
+            SecureLogger.warning("High nonce value detected: \(currentNonce) - consider rekeying", category: .encryption)
         }
-                
+        
         return combinedPayload
     }
     
@@ -303,16 +313,23 @@ class NoiseCipherState {
         if useExtractedNonce {
             // Extract nonce and ciphertext from combined payload
             guard let (extractedNonce, actualCiphertext) = try extractNonceFromCiphertextPayload(ciphertext) else {
-                SecureLogger.log("Decrypt failed: Could not extract nonce from payload")
+                SecureLogger.debug("Decrypt failed: Could not extract nonce from payload")
                 throw NoiseError.invalidCiphertext
             }
             
             // Validate nonce with sliding window replay protection
             guard isValidNonce(extractedNonce) else {
-                SecureLogger.log("Replay attack detected: nonce \(extractedNonce) rejected")
+                SecureLogger.debug("Replay attack detected: nonce \(extractedNonce) rejected")
                 throw NoiseError.replayDetected
             }
-
+            
+            // The 4-byte nonce prefix has been stripped, so the remaining bytes
+            // must still hold at least the 16-byte Poly1305 tag. The up-front
+            // `ciphertext.count >= 16` guard is not sufficient here (it counts
+            // the nonce), and `prefix(count - 16)` would trap on a short payload.
+            guard actualCiphertext.count >= 16 else {
+                throw NoiseError.invalidCiphertext
+            }
             // Split ciphertext and tag
             encryptedData = actualCiphertext.prefix(actualCiphertext.count - 16)
             tag = actualCiphertext.suffix(16)
@@ -338,25 +355,54 @@ class NoiseCipherState {
         
         // Log high nonce values that might indicate issues
         if decryptionNonce > Self.HIGH_NONCE_WARNING_THRESHOLD {
-            SecureLogger.log("High nonce value detected: \(decryptionNonce) - consider rekeying", category: SecureLogger.encryption, level: .warning)
+            SecureLogger.warning("High nonce value detected: \(decryptionNonce) - consider rekeying", category: .encryption)
         }
         
         do {
             let plaintext = try ChaChaPoly.open(sealedBox, using: key, authenticating: associatedData)
-            
+
+            // BCH-01-010: Atomic nonce state update
+            // Both replay window marking and nonce increment must complete together
+            // to prevent state desynchronization. We perform both after successful
+            // decryption only, ensuring state consistency on any failure path.
             if useExtractedNonce {
-                // Mark nonce as seen after successful decryption
                 markNonceAsSeen(decryptionNonce)
             }
             nonce += 1
+
             return plaintext
         } catch {
-            SecureLogger.log("Decrypt failed: \(error) for nonce \(decryptionNonce)")
-            // Log authentication failures with nonce info
-            SecureLogger.log("Decryption failed at nonce \(decryptionNonce)", category: SecureLogger.encryption, level: .error)
+            // Decryption failed - nonce state remains unchanged (atomic rollback)
+            SecureLogger.debug("Decrypt failed: \(error) for nonce \(decryptionNonce)")
+            SecureLogger.error("Decryption failed at nonce \(decryptionNonce)", category: .encryption)
             throw error
         }
     }
+    
+    /// Securely clear sensitive cryptographic data from memory
+    func clearSensitiveData() {
+        // Clear the symmetric key
+        key = nil
+        
+        // Reset nonce
+        nonce = 0
+        highestReceivedNonce = 0
+        
+        // Clear replay window
+        for i in 0..<replayWindow.count {
+            replayWindow[i] = 0
+        }
+    }
+
+    #if DEBUG
+    func setNonceForTesting(_ nonce: UInt64) {
+        self.nonce = nonce
+    }
+
+    func extractNonceFromCiphertextPayloadForTesting(_ combinedPayload: Data) throws -> (nonce: UInt64, ciphertext: Data)? {
+        try extractNonceFromCiphertextPayload(combinedPayload)
+    }
+    #endif
 }
 
 // MARK: - Symmetric State
@@ -365,7 +411,7 @@ class NoiseCipherState {
 /// Responsible for key derivation, protocol name hashing, and maintaining
 /// the chaining key that provides key separation between handshake messages.
 /// - Note: This class implements the SymmetricState object from the Noise spec
-class NoiseSymmetricState {
+final class NoiseSymmetricState {
     private var cipherState: NoiseCipherState
     private var chainingKey: Data
     private var hash: Data
@@ -378,7 +424,7 @@ class NoiseSymmetricState {
         if nameData.count <= 32 {
             self.hash = nameData + Data(repeating: 0, count: 32 - nameData.count)
         } else {
-            self.hash = Data(SHA256.hash(data: nameData))
+            self.hash = nameData.sha256Hash()
         }
         self.chainingKey = self.hash
     }
@@ -391,7 +437,7 @@ class NoiseSymmetricState {
     }
     
     func mixHash(_ data: Data) {
-        hash = Data(SHA256.hash(data: hash + data))
+        hash = (hash + data).sha256Hash()
     }
     
     func mixKeyAndHash(_ inputKeyMaterial: Data) {
@@ -432,17 +478,40 @@ class NoiseSymmetricState {
         }
     }
     
-    func split() -> (NoiseCipherState, NoiseCipherState) {
+    func split(useExtractedNonce: Bool) -> (NoiseCipherState, NoiseCipherState) {
         let output = hkdf(chainingKey: chainingKey, inputKeyMaterial: Data(), numOutputs: 2)
         let tempKey1 = SymmetricKey(data: output[0])
         let tempKey2 = SymmetricKey(data: output[1])
-        
-        let c1 = NoiseCipherState(key: tempKey1, useExtractedNonce: true)
-        let c2 = NoiseCipherState(key: tempKey2, useExtractedNonce: true)
-        
+
+        let c1 = NoiseCipherState(key: tempKey1, useExtractedNonce: useExtractedNonce)
+        let c2 = NoiseCipherState(key: tempKey2, useExtractedNonce: useExtractedNonce)
+
+        // BCH-01-010: Clear symmetric state after split per Noise spec
+        // The chaining key and hash should not be retained after handshake completes
+        clearSensitiveData()
+
         return (c1, c2)
     }
-    
+
+    /// BCH-01-010: Securely clear sensitive cryptographic state
+    /// Called after split() to clear chaining key and hash per Noise spec
+    func clearSensitiveData() {
+        // Clear chaining key by overwriting with zeros
+        let chainingKeyCount = chainingKey.count
+        chainingKey = Data(repeating: 0, count: chainingKeyCount)
+
+        // Clear hash by overwriting with zeros
+        let hashCount = hash.count
+        hash = Data(repeating: 0, count: hashCount)
+
+        // Clear the internal cipher state
+        cipherState.clearSensitiveData()
+    }
+
+    deinit {
+        clearSensitiveData()
+    }
+
     // HKDF implementation
     private func hkdf(chainingKey: Data, inputKeyMaterial: Data, numOutputs: Int) -> [Data] {
         let tempKey = HMAC<SHA256>.authenticationCode(for: inputKeyMaterial, using: SymmetricKey(data: chainingKey))
@@ -469,9 +538,10 @@ class NoiseSymmetricState {
 /// This is the main interface for establishing encrypted sessions between peers.
 /// Manages the handshake state machine, message patterns, and key derivation.
 /// - Important: Each handshake instance should only be used once
-class NoiseHandshakeState {
+final class NoiseHandshakeState {
     private let role: NoiseRole
     private let pattern: NoisePattern
+    private let keychain: KeychainManagerProtocol
     private var symmetricState: NoiseSymmetricState
     
     // Keys
@@ -487,9 +557,24 @@ class NoiseHandshakeState {
     private var messagePatterns: [[NoiseMessagePattern]] = []
     private var currentPattern = 0
     
-    init(role: NoiseRole, pattern: NoisePattern, localStaticKey: Curve25519.KeyAgreement.PrivateKey? = nil, remoteStaticKey: Curve25519.KeyAgreement.PublicKey? = nil) {
+    // Test support: predetermined ephemeral keys for test vectors
+    private var predeterminedEphemeralKey: Curve25519.KeyAgreement.PrivateKey?
+    private var prologueData: Data
+    
+    init(
+        role: NoiseRole,
+        pattern: NoisePattern,
+        keychain: KeychainManagerProtocol,
+        localStaticKey: Curve25519.KeyAgreement.PrivateKey? = nil,
+        remoteStaticKey: Curve25519.KeyAgreement.PublicKey? = nil,
+        prologue: Data = Data(),
+        predeterminedEphemeralKey: Curve25519.KeyAgreement.PrivateKey? = nil
+    ) {
         self.role = role
         self.pattern = pattern
+        self.keychain = keychain
+        self.prologueData = prologue
+        self.predeterminedEphemeralKey = predeterminedEphemeralKey
         
         // Initialize static keys
         if let localKey = localStaticKey {
@@ -510,17 +595,18 @@ class NoiseHandshakeState {
     }
     
     private func mixPreMessageKeys() {
-        // Mix prologue (empty for XX pattern normally)
-        symmetricState.mixHash(Data()) // Empty prologue for XX pattern
+        // Mix prologue
+        symmetricState.mixHash(self.prologueData)
         // For XX pattern, no pre-message keys
         // For IK/NK patterns, we'd mix the responder's static key here
         switch pattern {
         case .XX:
             break // No pre-message keys
-        case .IK, .NK:
+        case .IK, .NK, .X:
             if role == .initiator, let remoteStatic = remoteStaticPublic {
-                _ = symmetricState.getHandshakeHash()
                 symmetricState.mixHash(remoteStatic.rawRepresentation)
+            } else if role == .responder, let localStatic = localStaticPublic {
+                symmetricState.mixHash(localStatic.rawRepresentation)
             }
         }
     }
@@ -529,15 +615,20 @@ class NoiseHandshakeState {
         guard currentPattern < messagePatterns.count else {
             throw NoiseError.handshakeComplete
         }
-                
+        
         var messageBuffer = Data()
         let patterns = messagePatterns[currentPattern]
         
         for pattern in patterns {
             switch pattern {
             case .e:
-                // Generate ephemeral key
-                localEphemeralPrivate = Curve25519.KeyAgreement.PrivateKey()
+                // Generate ephemeral key (or use predetermined key for tests)
+                if let predetermined = predeterminedEphemeralKey {
+                    localEphemeralPrivate = predetermined
+                    predeterminedEphemeralKey = nil
+                } else {
+                    localEphemeralPrivate = Curve25519.KeyAgreement.PrivateKey()
+                }
                 localEphemeralPublic = localEphemeralPrivate!.publicKey
                 messageBuffer.append(localEphemeralPublic!.rawRepresentation)
                 symmetricState.mixHash(localEphemeralPublic!.rawRepresentation)
@@ -557,7 +648,10 @@ class NoiseHandshakeState {
                     throw NoiseError.missingKeys
                 }
                 let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteEphemeral)
-                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                var sharedData = shared.withUnsafeBytes { Data($0) }
+                symmetricState.mixKey(sharedData)
+                // Clear sensitive shared secret
+                keychain.secureClear(&sharedData)
                 
             case .es:
                 // DH(ephemeral, static) - direction depends on role
@@ -567,14 +661,20 @@ class NoiseHandshakeState {
                         throw NoiseError.missingKeys
                     }
                     let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteStatic)
-                    symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                    var sharedData = shared.withUnsafeBytes { Data($0) }
+                    symmetricState.mixKey(sharedData)
+                    // Clear sensitive shared secret
+                    keychain.secureClear(&sharedData)
                 } else {
                     guard let localStatic = localStaticPrivate,
                           let remoteEphemeral = remoteEphemeralPublic else {
                         throw NoiseError.missingKeys
                     }
                     let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteEphemeral)
-                    symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                    var sharedData = shared.withUnsafeBytes { Data($0) }
+                    symmetricState.mixKey(sharedData)
+                    // Clear sensitive shared secret
+                    keychain.secureClear(&sharedData)
                 }
                 
             case .se:
@@ -585,14 +685,20 @@ class NoiseHandshakeState {
                         throw NoiseError.missingKeys
                     }
                     let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteEphemeral)
-                    symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                    var sharedData = shared.withUnsafeBytes { Data($0) }
+                    symmetricState.mixKey(sharedData)
+                    // Clear sensitive shared secret
+                    keychain.secureClear(&sharedData)
                 } else {
                     guard let localEphemeral = localEphemeralPrivate,
                           let remoteStatic = remoteStaticPublic else {
                         throw NoiseError.missingKeys
                     }
                     let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteStatic)
-                    symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                    var sharedData = shared.withUnsafeBytes { Data($0) }
+                    symmetricState.mixKey(sharedData)
+                    // Clear sensitive shared secret
+                    keychain.secureClear(&sharedData)
                 }
                 
             case .ss:
@@ -602,7 +708,10 @@ class NoiseHandshakeState {
                     throw NoiseError.missingKeys
                 }
                 let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteStatic)
-                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                var sharedData = shared.withUnsafeBytes { Data($0) }
+                symmetricState.mixKey(sharedData)
+                // Clear sensitive shared secret
+                keychain.secureClear(&sharedData)
             }
         }
         
@@ -619,7 +728,7 @@ class NoiseHandshakeState {
         guard currentPattern < messagePatterns.count else {
             throw NoiseError.handshakeComplete
         }
-                
+        
         var buffer = message
         let patterns = messagePatterns[currentPattern]
         
@@ -636,7 +745,7 @@ class NoiseHandshakeState {
                 do {
                     remoteEphemeralPublic = try NoiseHandshakeState.validatePublicKey(ephemeralData)
                 } catch {
-                    SecureLogger.log("Invalid ephemeral public key received", category: SecureLogger.security, level: .warning)
+                    SecureLogger.warning("Invalid ephemeral public key received", category: .security)
                     throw NoiseError.invalidMessage
                 }
                 symmetricState.mixHash(ephemeralData)
@@ -653,7 +762,7 @@ class NoiseHandshakeState {
                     let decrypted = try symmetricState.decryptAndHash(staticData)
                     remoteStaticPublic = try NoiseHandshakeState.validatePublicKey(decrypted)
                 } catch {
-                    SecureLogger.logSecurityEvent(.authenticationFailed(peerID: "Unknown - handshake"), level: .error)
+                    SecureLogger.error(.authenticationFailed(peerID: "Unknown - handshake"))
                     throw NoiseError.authenticationFailure
                 }
                 
@@ -678,8 +787,11 @@ class NoiseHandshakeState {
                 throw NoiseError.missingKeys
             }
             let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteEphemeral)
-            symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
-            
+            var sharedData = shared.withUnsafeBytes { Data($0) }
+            symmetricState.mixKey(sharedData)
+            // Clear sensitive shared secret
+            keychain.secureClear(&sharedData)
+
         case .es:
             if role == .initiator {
                 guard let localEphemeral = localEphemeralPrivate,
@@ -687,14 +799,20 @@ class NoiseHandshakeState {
                     throw NoiseError.missingKeys
                 }
                 let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteStatic)
-                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                var sharedData = shared.withUnsafeBytes { Data($0) }
+                symmetricState.mixKey(sharedData)
+                // Clear sensitive shared secret
+                keychain.secureClear(&sharedData)
             } else {
                 guard let localStatic = localStaticPrivate,
                       let remoteEphemeral = remoteEphemeralPublic else {
                     throw NoiseError.missingKeys
                 }
                 let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteEphemeral)
-                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                var sharedData = shared.withUnsafeBytes { Data($0) }
+                symmetricState.mixKey(sharedData)
+                // Clear sensitive shared secret
+                keychain.secureClear(&sharedData)
             }
             
         case .se:
@@ -704,14 +822,20 @@ class NoiseHandshakeState {
                     throw NoiseError.missingKeys
                 }
                 let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteEphemeral)
-                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                var sharedData = shared.withUnsafeBytes { Data($0) }
+                symmetricState.mixKey(sharedData)
+                // Clear sensitive shared secret
+                keychain.secureClear(&sharedData)
             } else {
                 guard let localEphemeral = localEphemeralPrivate,
                       let remoteStatic = remoteStaticPublic else {
                     throw NoiseError.missingKeys
                 }
                 let shared = try localEphemeral.sharedSecretFromKeyAgreement(with: remoteStatic)
-                symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
+                var sharedData = shared.withUnsafeBytes { Data($0) }
+                symmetricState.mixKey(sharedData)
+                // Clear sensitive shared secret
+                keychain.secureClear(&sharedData)
             }
             
         case .ss:
@@ -720,9 +844,12 @@ class NoiseHandshakeState {
                 throw NoiseError.missingKeys
             }
             let shared = try localStatic.sharedSecretFromKeyAgreement(with: remoteStatic)
-            symmetricState.mixKey(shared.withUnsafeBytes { Data($0) })
-            
-        default:
+            var sharedData = shared.withUnsafeBytes { Data($0) }
+            symmetricState.mixKey(sharedData)
+            // Clear sensitive shared secret
+            keychain.secureClear(&sharedData)
+
+        case .e, .s:
             break
         }
     }
@@ -731,16 +858,20 @@ class NoiseHandshakeState {
         return currentPattern >= messagePatterns.count
     }
     
-    func getTransportCiphers() throws -> (send: NoiseCipherState, receive: NoiseCipherState) {
+    func getTransportCiphers(useExtractedNonce: Bool) throws -> (send: NoiseCipherState, receive: NoiseCipherState, handshakeHash: Data) {
         guard isHandshakeComplete() else {
             throw NoiseError.handshakeNotComplete
         }
-        
-        let (c1, c2) = symmetricState.split()
-        
+
+        // BCH-01-010: Capture handshake hash BEFORE split() clears symmetric state
+        let finalHandshakeHash = symmetricState.getHandshakeHash()
+
+        let (c1, c2) = symmetricState.split(useExtractedNonce: useExtractedNonce)
+
         // Initiator uses c1 for sending, c2 for receiving
         // Responder uses c2 for sending, c1 for receiving
-        return role == .initiator ? (c1, c2) : (c2, c1)
+        let ciphers = role == .initiator ? (c1, c2) : (c2, c1)
+        return (send: ciphers.0, receive: ciphers.1, handshakeHash: finalHandshakeHash)
     }
     
     func getRemoteStaticPublicKey() -> Curve25519.KeyAgreement.PublicKey? {
@@ -750,6 +881,20 @@ class NoiseHandshakeState {
     func getHandshakeHash() -> Data {
         return symmetricState.getHandshakeHash()
     }
+
+    #if DEBUG
+    func performDHOperationForTesting(_ pattern: NoiseMessagePattern) throws {
+        try performDHOperation(pattern)
+    }
+
+    func setCurrentPatternForTesting(_ currentPattern: Int) {
+        self.currentPattern = currentPattern
+    }
+
+    func setRemoteEphemeralPublicKeyForTesting(_ key: Curve25519.KeyAgreement.PublicKey?) {
+        self.remoteEphemeralPublic = key
+    }
+    #endif
 }
 
 // MARK: - Pattern Extensions
@@ -760,6 +905,7 @@ extension NoisePattern {
         case .XX: return "XX"
         case .IK: return "IK"
         case .NK: return "NK"
+        case .X: return "X"
         }
     }
     
@@ -781,6 +927,10 @@ extension NoisePattern {
                 [.e, .es],      // -> e, es
                 [.e, .ee]       // <- e, ee
             ]
+        case .X:
+            return [
+                [.e, .es, .s, .ss] // -> e, es, s, ss (single one-way message)
+            ]
         }
     }
 }
@@ -801,22 +951,47 @@ enum NoiseError: Error {
     case nonceExceeded
 }
 
+// MARK: - Constant-Time Operations
+
+/// BCH-01-010: Constant-time comparison to prevent timing side-channel attacks
+/// This function compares two Data objects in constant time, preventing
+/// information leakage via timing analysis.
+private func constantTimeCompare(_ a: Data, _ b: Data) -> Bool {
+    guard a.count == b.count else { return false }
+
+    var result: UInt8 = 0
+    for i in 0..<a.count {
+        result |= a[a.startIndex.advanced(by: i)] ^ b[b.startIndex.advanced(by: i)]
+    }
+    return result == 0
+}
+
+/// BCH-01-010: Constant-time check if all bytes are zero
+private func constantTimeIsZero(_ data: Data) -> Bool {
+    var result: UInt8 = 0
+    for byte in data {
+        result |= byte
+    }
+    return result == 0
+}
+
 // MARK: - Key Validation
 
 extension NoiseHandshakeState {
     /// Validate a Curve25519 public key
     /// Checks for weak/invalid keys that could compromise security
+    /// BCH-01-010: Uses constant-time operations to prevent timing side-channels
     static func validatePublicKey(_ keyData: Data) throws -> Curve25519.KeyAgreement.PublicKey {
         // Check key length
         guard keyData.count == 32 else {
             throw NoiseError.invalidPublicKey
         }
-        
-        // Check for all-zero key (point at infinity)
-        if keyData.allSatisfy({ $0 == 0 }) {
+
+        // BCH-01-010: Constant-time check for all-zero key (point at infinity)
+        if constantTimeIsZero(keyData) {
             throw NoiseError.invalidPublicKey
         }
-        
+
         // Check for low-order points that could enable small subgroup attacks
         // These are the known bad points for Curve25519
         let lowOrderPoints: [Data] = [
@@ -837,20 +1012,28 @@ extension NoiseHandshakeState {
                   0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                   0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff])  // Another bad point
         ]
-        
-        // Check against known bad points
-        if lowOrderPoints.contains(keyData) {
-            SecureLogger.log("Low-order point detected", category: SecureLogger.security, level: .warning)
+
+        // BCH-01-010: Constant-time check against known bad points
+        // We check all points and accumulate matches to avoid early exit timing leaks
+        var foundBadPoint = false
+        for badPoint in lowOrderPoints {
+            if constantTimeCompare(keyData, badPoint) {
+                foundBadPoint = true
+            }
+        }
+
+        if foundBadPoint {
+            SecureLogger.warning("Low-order point detected", category: .security)
             throw NoiseError.invalidPublicKey
         }
-        
+
         // Try to create the key - CryptoKit will validate curve points internally
         do {
             let publicKey = try Curve25519.KeyAgreement.PublicKey(rawRepresentation: keyData)
             return publicKey
         } catch {
             // If CryptoKit rejects it, it's invalid
-            SecureLogger.log("CryptoKit validation failed", category: SecureLogger.security, level: .warning)
+            SecureLogger.warning("CryptoKit validation failed", category: .security)
             throw NoiseError.invalidPublicKey
         }
     }

bitchat/Noise/NoiseRateLimiter.swift

@@ -0,0 +1,96 @@
+//
+// NoiseRateLimiter.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import BitLogger
+import BitFoundation
+import Foundation
+
+final class NoiseRateLimiter {
+    private var handshakeTimestamps: [PeerID: [Date]] = [:]
+    private var messageTimestamps: [PeerID: [Date]] = [:]
+    
+    // Global rate limiting
+    private var globalHandshakeTimestamps: [Date] = []
+    private var globalMessageTimestamps: [Date] = []
+    
+    private let queue = DispatchQueue(label: "chat.bitchat.noise.ratelimit", attributes: .concurrent)
+    
+    func allowHandshake(from peerID: PeerID) -> Bool {
+        return queue.sync(flags: .barrier) {
+            let now = Date()
+            let oneMinuteAgo = now.addingTimeInterval(-60)
+            
+            // Check global rate limit first
+            globalHandshakeTimestamps = globalHandshakeTimestamps.filter { $0 > oneMinuteAgo }
+            if globalHandshakeTimestamps.count >= NoiseSecurityConstants.maxGlobalHandshakesPerMinute {
+                SecureLogger.warning("Global handshake rate limit exceeded: \(globalHandshakeTimestamps.count)/\(NoiseSecurityConstants.maxGlobalHandshakesPerMinute) per minute", category: .security)
+                return false
+            }
+            
+            // Check per-peer rate limit
+            var timestamps = handshakeTimestamps[peerID] ?? []
+            timestamps = timestamps.filter { $0 > oneMinuteAgo }
+            
+            if timestamps.count >= NoiseSecurityConstants.maxHandshakesPerMinute {
+                SecureLogger.warning("Per-peer handshake rate limit exceeded for \(peerID): \(timestamps.count)/\(NoiseSecurityConstants.maxHandshakesPerMinute) per minute", category: .security)
+                return false
+            }
+            
+            // Record new handshake
+            timestamps.append(now)
+            handshakeTimestamps[peerID] = timestamps
+            globalHandshakeTimestamps.append(now)
+            return true
+        }
+    }
+    
+    func allowMessage(from peerID: PeerID) -> Bool {
+        return queue.sync(flags: .barrier) {
+            let now = Date()
+            let oneSecondAgo = now.addingTimeInterval(-1)
+            
+            // Check global rate limit first
+            globalMessageTimestamps = globalMessageTimestamps.filter { $0 > oneSecondAgo }
+            if globalMessageTimestamps.count >= NoiseSecurityConstants.maxGlobalMessagesPerSecond {
+                SecureLogger.warning("Global message rate limit exceeded: \(globalMessageTimestamps.count)/\(NoiseSecurityConstants.maxGlobalMessagesPerSecond) per second", category: .security)
+                return false
+            }
+            
+            // Check per-peer rate limit
+            var timestamps = messageTimestamps[peerID] ?? []
+            timestamps = timestamps.filter { $0 > oneSecondAgo }
+            
+            if timestamps.count >= NoiseSecurityConstants.maxMessagesPerSecond {
+                SecureLogger.warning("Per-peer message rate limit exceeded for \(peerID): \(timestamps.count)/\(NoiseSecurityConstants.maxMessagesPerSecond) per second", category: .security)
+                return false
+            }
+            
+            // Record new message
+            timestamps.append(now)
+            messageTimestamps[peerID] = timestamps
+            globalMessageTimestamps.append(now)
+            return true
+        }
+    }
+    
+    func reset(for peerID: PeerID) {
+        queue.async(flags: .barrier) {
+            self.handshakeTimestamps.removeValue(forKey: peerID)
+            self.messageTimestamps.removeValue(forKey: peerID)
+        }
+    }
+
+    func resetAll() {
+        queue.async(flags: .barrier) {
+            self.handshakeTimestamps.removeAll()
+            self.messageTimestamps.removeAll()
+            self.globalHandshakeTimestamps.removeAll()
+            self.globalMessageTimestamps.removeAll()
+        }
+    }
+}

bitchat/Noise/NoiseSecurityConsiderations.swift

@@ -1,227 +0,0 @@
-//
-// NoiseSecurityConsiderations.swift
-// bitchat
-//
-// This is free and unencumbered software released into the public domain.
-// For more information, see <https://unlicense.org>
-//
-
-import Foundation
-import CryptoKit
-
-// MARK: - Security Constants
-
-enum NoiseSecurityConstants {
-    // Maximum message size to prevent memory exhaustion
-    static let maxMessageSize = 65535 // 64KB as per Noise spec
-    
-    // Maximum handshake message size
-    static let maxHandshakeMessageSize = 2048 // 2KB to accommodate XX pattern
-    
-    // Session timeout - sessions older than this should be renegotiated
-    static let sessionTimeout: TimeInterval = 86400 // 24 hours
-    
-    // Maximum number of messages before rekey (2^64 - 1 is the nonce limit)
-    static let maxMessagesPerSession: UInt64 = 1_000_000_000 // 1 billion messages
-    
-    // Handshake timeout - abandon incomplete handshakes
-    static let handshakeTimeout: TimeInterval = 60 // 1 minute
-    
-    // Maximum concurrent sessions per peer
-    static let maxSessionsPerPeer = 3
-    
-    // Rate limiting
-    static let maxHandshakesPerMinute = 10
-    static let maxMessagesPerSecond = 100
-    
-    // Global rate limiting (across all peers)
-    static let maxGlobalHandshakesPerMinute = 30
-    static let maxGlobalMessagesPerSecond = 500
-}
-
-// MARK: - Security Validations
-
-struct NoiseSecurityValidator {
-    
-    /// Validate message size
-    static func validateMessageSize(_ data: Data) -> Bool {
-        return data.count <= NoiseSecurityConstants.maxMessageSize
-    }
-    
-    /// Validate handshake message size
-    static func validateHandshakeMessageSize(_ data: Data) -> Bool {
-        return data.count <= NoiseSecurityConstants.maxHandshakeMessageSize
-    }
-    
-    /// Validate peer ID format
-    static func validatePeerID(_ peerID: String) -> Bool {
-        // Peer ID should be reasonable length and contain valid characters
-        let validCharset = CharacterSet.alphanumerics.union(CharacterSet(charactersIn: "-_"))
-        return peerID.count > 0 && 
-               peerID.count <= 64 && 
-               peerID.rangeOfCharacter(from: validCharset.inverted) == nil
-    }
-}
-
-// MARK: - Enhanced Noise Session with Security
-
-class SecureNoiseSession: NoiseSession {
-    private(set) var messageCount: UInt64 = 0
-    private let sessionStartTime = Date()
-    private(set) var lastActivityTime = Date()
-    
-    override func encrypt(_ plaintext: Data) throws -> Data {
-        // Check session age
-        if Date().timeIntervalSince(sessionStartTime) > NoiseSecurityConstants.sessionTimeout {
-            throw NoiseSecurityError.sessionExpired
-        }
-        
-        // Check message count
-        if messageCount >= NoiseSecurityConstants.maxMessagesPerSession {
-            throw NoiseSecurityError.sessionExhausted
-        }
-        
-        // Validate message size
-        guard NoiseSecurityValidator.validateMessageSize(plaintext) else {
-            throw NoiseSecurityError.messageTooLarge
-        }
-        
-        let encrypted = try super.encrypt(plaintext)
-        messageCount += 1
-        lastActivityTime = Date()
-        
-        return encrypted
-    }
-    
-    override func decrypt(_ ciphertext: Data) throws -> Data {
-        // Check session age
-        if Date().timeIntervalSince(sessionStartTime) > NoiseSecurityConstants.sessionTimeout {
-            throw NoiseSecurityError.sessionExpired
-        }
-        
-        // Validate message size
-        guard NoiseSecurityValidator.validateMessageSize(ciphertext) else {
-            throw NoiseSecurityError.messageTooLarge
-        }
-        
-        let decrypted = try super.decrypt(ciphertext)
-        lastActivityTime = Date()
-        
-        return decrypted
-    }
-    
-    func needsRenegotiation() -> Bool {
-        // Check if we've used more than 90% of message limit
-        let messageThreshold = UInt64(Double(NoiseSecurityConstants.maxMessagesPerSession) * 0.9)
-        if messageCount >= messageThreshold {
-            return true
-        }
-        
-        // Check if last activity was more than 30 minutes ago
-        if Date().timeIntervalSince(lastActivityTime) > NoiseSecurityConstants.sessionTimeout {
-            return true
-        }
-        
-        return false
-    }
-    
-    // MARK: - Testing Support
-    #if DEBUG
-    func setLastActivityTimeForTesting(_ date: Date) {
-        lastActivityTime = date
-    }
-    
-    func setMessageCountForTesting(_ count: UInt64) {
-        messageCount = count
-    }
-    #endif
-}
-
-// MARK: - Rate Limiter
-
-class NoiseRateLimiter {
-    private var handshakeTimestamps: [String: [Date]] = [:] // peerID -> timestamps
-    private var messageTimestamps: [String: [Date]] = [:] // peerID -> timestamps
-    
-    // Global rate limiting
-    private var globalHandshakeTimestamps: [Date] = []
-    private var globalMessageTimestamps: [Date] = []
-    
-    private let queue = DispatchQueue(label: "chat.bitchat.noise.ratelimit", attributes: .concurrent)
-    
-    func allowHandshake(from peerID: String) -> Bool {
-        return queue.sync(flags: .barrier) {
-            let now = Date()
-            let oneMinuteAgo = now.addingTimeInterval(-60)
-            
-            // Check global rate limit first
-            globalHandshakeTimestamps = globalHandshakeTimestamps.filter { $0 > oneMinuteAgo }
-            if globalHandshakeTimestamps.count >= NoiseSecurityConstants.maxGlobalHandshakesPerMinute {
-                SecureLogger.log("Global handshake rate limit exceeded: \(globalHandshakeTimestamps.count)/\(NoiseSecurityConstants.maxGlobalHandshakesPerMinute) per minute", category: SecureLogger.security, level: .warning)
-                return false
-            }
-            
-            // Check per-peer rate limit
-            var timestamps = handshakeTimestamps[peerID] ?? []
-            timestamps = timestamps.filter { $0 > oneMinuteAgo }
-            
-            if timestamps.count >= NoiseSecurityConstants.maxHandshakesPerMinute {
-                SecureLogger.log("Per-peer handshake rate limit exceeded for \(peerID): \(timestamps.count)/\(NoiseSecurityConstants.maxHandshakesPerMinute) per minute", category: SecureLogger.security, level: .warning)
-                return false
-            }
-            
-            // Record new handshake
-            timestamps.append(now)
-            handshakeTimestamps[peerID] = timestamps
-            globalHandshakeTimestamps.append(now)
-            return true
-        }
-    }
-    
-    func allowMessage(from peerID: String) -> Bool {
-        return queue.sync(flags: .barrier) {
-            let now = Date()
-            let oneSecondAgo = now.addingTimeInterval(-1)
-            
-            // Check global rate limit first
-            globalMessageTimestamps = globalMessageTimestamps.filter { $0 > oneSecondAgo }
-            if globalMessageTimestamps.count >= NoiseSecurityConstants.maxGlobalMessagesPerSecond {
-                SecureLogger.log("Global message rate limit exceeded: \(globalMessageTimestamps.count)/\(NoiseSecurityConstants.maxGlobalMessagesPerSecond) per second", category: SecureLogger.security, level: .warning)
-                return false
-            }
-            
-            // Check per-peer rate limit
-            var timestamps = messageTimestamps[peerID] ?? []
-            timestamps = timestamps.filter { $0 > oneSecondAgo }
-            
-            if timestamps.count >= NoiseSecurityConstants.maxMessagesPerSecond {
-                SecureLogger.log("Per-peer message rate limit exceeded for \(peerID): \(timestamps.count)/\(NoiseSecurityConstants.maxMessagesPerSecond) per second", category: SecureLogger.security, level: .warning)
-                return false
-            }
-            
-            // Record new message
-            timestamps.append(now)
-            messageTimestamps[peerID] = timestamps
-            globalMessageTimestamps.append(now)
-            return true
-        }
-    }
-    
-    func reset(for peerID: String) {
-        queue.async(flags: .barrier) {
-            self.handshakeTimestamps.removeValue(forKey: peerID)
-            self.messageTimestamps.removeValue(forKey: peerID)
-        }
-    }
-}
-
-// MARK: - Security Errors
-
-enum NoiseSecurityError: Error {
-    case sessionExpired
-    case sessionExhausted
-    case messageTooLarge
-    case invalidPeerID
-    case rateLimitExceeded
-    case handshakeTimeout
-}

bitchat/Noise/NoiseSecurityConstants.swift

@@ -0,0 +1,37 @@
+//
+// NoiseSecurityConstants.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+enum NoiseSecurityConstants {
+    // Maximum message size to prevent memory exhaustion
+    static let maxMessageSize = 65535 // 64KB as per Noise spec
+    
+    // Maximum handshake message size
+    static let maxHandshakeMessageSize = 2048 // 2KB to accommodate XX pattern
+    
+    // Session timeout - sessions older than this should be renegotiated
+    static let sessionTimeout: TimeInterval = 86400 // 24 hours
+    
+    // Maximum number of messages before rekey (2^64 - 1 is the nonce limit)
+    static let maxMessagesPerSession: UInt64 = 1_000_000_000 // 1 billion messages
+    
+    // Handshake timeout - abandon incomplete handshakes
+    static let handshakeTimeout: TimeInterval = 60 // 1 minute
+    
+    // Maximum concurrent sessions per peer
+    static let maxSessionsPerPeer = 3
+    
+    // Rate limiting
+    static let maxHandshakesPerMinute = 10
+    static let maxMessagesPerSecond = 100
+    
+    // Global rate limiting (across all peers)
+    static let maxGlobalHandshakesPerMinute = 30
+    static let maxGlobalMessagesPerSecond = 500
+}

bitchat/Noise/NoiseSecurityError.swift

@@ -0,0 +1,18 @@
+//
+// NoiseSecurityError.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+enum NoiseSecurityError: Error {
+    case sessionExpired
+    case sessionExhausted
+    case messageTooLarge
+    case invalidPeerID
+    case rateLimitExceeded
+    case handshakeTimeout
+}

bitchat/Noise/NoiseSecurityValidator.swift

@@ -0,0 +1,22 @@
+//
+// NoiseSecurityValidator.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+struct NoiseSecurityValidator {
+    
+    /// Validate message size
+    static func validateMessageSize(_ data: Data) -> Bool {
+        return data.count <= NoiseSecurityConstants.maxMessageSize
+    }
+    
+    /// Validate handshake message size
+    static func validateHandshakeMessageSize(_ data: Data) -> Bool {
+        return data.count <= NoiseSecurityConstants.maxHandshakeMessageSize
+    }
+}

bitchat/Noise/NoiseSession.swift

@@ -6,37 +6,15 @@
 // For more information, see <https://unlicense.org>
 //
 
+import BitLogger
 import Foundation
 import CryptoKit
-import os.log
-
-// MARK: - Noise Session State
-
-enum NoiseSessionState: Equatable {
-    case uninitialized
-    case handshaking
-    case established
-    case failed(Error)
-    
-    static func == (lhs: NoiseSessionState, rhs: NoiseSessionState) -> Bool {
-        switch (lhs, rhs) {
-        case (.uninitialized, .uninitialized),
-             (.handshaking, .handshaking),
-             (.established, .established):
-            return true
-        case (.failed, .failed):
-            return true // We don't compare the errors
-        default:
-            return false
-        }
-    }
-}
-
-// MARK: - Noise Session
+import BitFoundation
 
 class NoiseSession {
-    let peerID: String
+    let peerID: PeerID
     let role: NoiseRole
+    private let keychain: KeychainManagerProtocol
     private var state: NoiseSessionState = .uninitialized
     private var handshakeState: NoiseHandshakeState?
     private var sendCipher: NoiseCipherState?
@@ -53,9 +31,16 @@ class NoiseSession {
     // Thread safety
     private let sessionQueue = DispatchQueue(label: "chat.bitchat.noise.session", attributes: .concurrent)
     
-    init(peerID: String, role: NoiseRole, localStaticKey: Curve25519.KeyAgreement.PrivateKey, remoteStaticKey: Curve25519.KeyAgreement.PublicKey? = nil) {
+    init(
+        peerID: PeerID,
+        role: NoiseRole,
+        keychain: KeychainManagerProtocol,
+        localStaticKey: Curve25519.KeyAgreement.PrivateKey,
+        remoteStaticKey: Curve25519.KeyAgreement.PublicKey? = nil
+    ) {
         self.peerID = peerID
         self.role = role
+        self.keychain = keychain
         self.localStaticKey = localStaticKey
         self.remoteStaticPublicKey = remoteStaticKey
     }
@@ -72,6 +57,7 @@ class NoiseSession {
             handshakeState = NoiseHandshakeState(
                 role: role,
                 pattern: .XX,
+                keychain: keychain,
                 localStaticKey: localStaticKey,
                 remoteStaticKey: nil
             )
@@ -92,18 +78,19 @@ class NoiseSession {
     
     func processHandshakeMessage(_ message: Data) throws -> Data? {
         return try sessionQueue.sync(flags: .barrier) {
-            SecureLogger.log("NoiseSession[\(peerID)]: Processing handshake message, current state: \(state), role: \(role)", category: SecureLogger.noise, level: .info)
+            SecureLogger.debug("NoiseSession[\(peerID)]: Processing handshake message, current state: \(state), role: \(role)")
             
             // Initialize handshake state if needed (for responders)
             if state == .uninitialized && role == .responder {
                 handshakeState = NoiseHandshakeState(
                     role: role,
                     pattern: .XX,
+                    keychain: keychain,
                     localStaticKey: localStaticKey,
                     remoteStaticKey: nil
                 )
                 state = .handshaking
-                SecureLogger.log("NoiseSession[\(peerID)]: Initialized handshake state for responder", category: SecureLogger.noise, level: .info)
+                SecureLogger.debug("NoiseSession[\(peerID)]: Initialized handshake state for responder")
             }
             
             guard case .handshaking = state, let handshake = handshakeState else {
@@ -112,52 +99,52 @@ class NoiseSession {
             
             // Process incoming message
             _ = try handshake.readMessage(message)
-            SecureLogger.log("NoiseSession[\(peerID)]: Read handshake message, checking if complete", category: SecureLogger.noise, level: .info)
+            SecureLogger.debug("NoiseSession[\(peerID)]: Read handshake message, checking if complete")
             
             // Check if handshake is complete
             if handshake.isHandshakeComplete() {
-                // Get transport ciphers
-                let (send, receive) = try handshake.getTransportCiphers()
+                // Get transport ciphers and handshake hash (hash captured before split clears state)
+                let (send, receive, hash) = try handshake.getTransportCiphers(useExtractedNonce: true)
                 sendCipher = send
                 receiveCipher = receive
-                
+
                 // Store remote static key
                 remoteStaticPublicKey = handshake.getRemoteStaticPublicKey()
-                
+
                 // Store handshake hash for channel binding
-                handshakeHash = handshake.getHandshakeHash()
-                
+                handshakeHash = hash
+
                 state = .established
                 handshakeState = nil // Clear handshake state
-                
-                SecureLogger.log("NoiseSession[\(peerID)]: Handshake complete (no response needed), transitioning to established", category: SecureLogger.noise, level: .info)
-                SecureLogger.logSecurityEvent(.handshakeCompleted(peerID: peerID))
-                
+
+                SecureLogger.debug("NoiseSession[\(peerID)]: Handshake complete (no response needed), transitioning to established")
+                SecureLogger.info(.handshakeCompleted(peerID: peerID.id))
+
                 return nil
             } else {
                 // Generate response
                 let response = try handshake.writeMessage()
                 sentHandshakeMessages.append(response)
-                SecureLogger.log("NoiseSession[\(peerID)]: Generated handshake response of size \(response.count)", category: SecureLogger.noise, level: .info)
+                SecureLogger.debug("NoiseSession[\(peerID)]: Generated handshake response of size \(response.count)")
                 
                 // Check if handshake is complete after writing
                 if handshake.isHandshakeComplete() {
-                    // Get transport ciphers
-                    let (send, receive) = try handshake.getTransportCiphers()
+                    // Get transport ciphers and handshake hash (hash captured before split clears state)
+                    let (send, receive, hash) = try handshake.getTransportCiphers(useExtractedNonce: true)
                     sendCipher = send
                     receiveCipher = receive
-                    
+
                     // Store remote static key
                     remoteStaticPublicKey = handshake.getRemoteStaticPublicKey()
-                    
+
                     // Store handshake hash for channel binding
-                    handshakeHash = handshake.getHandshakeHash()
-                    
+                    handshakeHash = hash
+
                     state = .established
                     handshakeState = nil // Clear handshake state
-                    
-                    SecureLogger.log("NoiseSession[\(peerID)]: Handshake complete after writing response, transitioning to established", category: SecureLogger.noise, level: .info)
-                    SecureLogger.logSecurityEvent(.handshakeCompleted(peerID: peerID))
+
+                    SecureLogger.debug("NoiseSession[\(peerID)]: Handshake complete after writing response, transitioning to established")
+                    SecureLogger.info(.handshakeCompleted(peerID: peerID.id))
                 }
                 
                 return response
@@ -210,262 +197,34 @@ class NoiseSession {
         }
     }
     
-    func getHandshakeHash() -> Data? {
-        return sessionQueue.sync {
-            return handshakeHash
-        }
-    }
-    
     func reset() {
         sessionQueue.sync(flags: .barrier) {
             let wasEstablished = state == .established
             state = .uninitialized
             handshakeState = nil
+            
+            // Clear sensitive cipher states
+            sendCipher?.clearSensitiveData()
+            receiveCipher?.clearSensitiveData()
             sendCipher = nil
             receiveCipher = nil
+            
+            // Clear sent handshake messages
+            for i in 0..<sentHandshakeMessages.count {
+                var message = sentHandshakeMessages[i]
+                keychain.secureClear(&message)
+            }
             sentHandshakeMessages.removeAll()
+            
+            // Clear handshake hash
+            if var hash = handshakeHash {
+                keychain.secureClear(&hash)
+            }
             handshakeHash = nil
             
             if wasEstablished {
-                SecureLogger.logSecurityEvent(.sessionExpired(peerID: peerID))
+                SecureLogger.info(.sessionExpired(peerID: peerID.id))
             }
         }
     }
 }
-
-// MARK: - Session Manager
-
-class NoiseSessionManager {
-    private var sessions: [String: NoiseSession] = [:]
-    private let localStaticKey: Curve25519.KeyAgreement.PrivateKey
-    private let managerQueue = DispatchQueue(label: "chat.bitchat.noise.manager", attributes: .concurrent)
-    
-    // Callbacks
-    var onSessionEstablished: ((String, Curve25519.KeyAgreement.PublicKey) -> Void)?
-    var onSessionFailed: ((String, Error) -> Void)?
-    
-    init(localStaticKey: Curve25519.KeyAgreement.PrivateKey) {
-        self.localStaticKey = localStaticKey
-    }
-    
-    // MARK: - Session Management
-    
-    func createSession(for peerID: String, role: NoiseRole) -> NoiseSession {
-        return managerQueue.sync(flags: .barrier) {
-            let session = SecureNoiseSession(
-                peerID: peerID,
-                role: role,
-                localStaticKey: localStaticKey
-            )
-            sessions[peerID] = session
-            return session
-        }
-    }
-    
-    func getSession(for peerID: String) -> NoiseSession? {
-        return managerQueue.sync {
-            return sessions[peerID]
-        }
-    }
-    
-    func removeSession(for peerID: String) {
-        managerQueue.sync(flags: .barrier) {
-            if let session = sessions[peerID], session.isEstablished() {
-                SecureLogger.logSecurityEvent(.sessionExpired(peerID: peerID))
-            }
-            _ = sessions.removeValue(forKey: peerID)
-        }
-    }
-    
-    func migrateSession(from oldPeerID: String, to newPeerID: String) {
-        managerQueue.sync(flags: .barrier) {
-            // Check if we have a session for the old peer ID
-            if let session = sessions[oldPeerID] {
-                // Move the session to the new peer ID
-                sessions[newPeerID] = session
-                _ = sessions.removeValue(forKey: oldPeerID)
-                
-                SecureLogger.log("Migrated Noise session from \(oldPeerID) to \(newPeerID)", category: SecureLogger.noise, level: .info)
-            }
-        }
-    }
-    
-    func getEstablishedSessions() -> [String: NoiseSession] {
-        return managerQueue.sync {
-            return sessions.filter { $0.value.isEstablished() }
-        }
-    }
-    
-    // MARK: - Handshake Helpers
-    
-    func initiateHandshake(with peerID: String) throws -> Data {
-        return try managerQueue.sync(flags: .barrier) {
-            // Check if we already have an established session
-            if let existingSession = sessions[peerID], existingSession.isEstablished() {
-                // Session already established, don't recreate
-                throw NoiseSessionError.alreadyEstablished
-            }
-            
-            // Remove any existing non-established session
-            if let existingSession = sessions[peerID], !existingSession.isEstablished() {
-                _ = sessions.removeValue(forKey: peerID)
-            }
-            
-            // Create new initiator session
-            let session = SecureNoiseSession(
-                peerID: peerID,
-                role: .initiator,
-                localStaticKey: localStaticKey
-            )
-            sessions[peerID] = session
-            
-            do {
-                let handshakeData = try session.startHandshake()
-                return handshakeData
-            } catch {
-                // Clean up failed session
-                _ = sessions.removeValue(forKey: peerID)
-                SecureLogger.logSecurityEvent(.handshakeFailed(peerID: peerID, error: error.localizedDescription), level: .error)
-                throw error
-            }
-        }
-    }
-    
-    func handleIncomingHandshake(from peerID: String, message: Data) throws -> Data? {
-        // Process everything within the synchronized block to prevent race conditions
-        return try managerQueue.sync(flags: .barrier) {
-            var shouldCreateNew = false
-            var existingSession: NoiseSession? = nil
-            
-            if let existing = sessions[peerID] {
-                // If we have an established session, the peer must have cleared their session
-                // for a good reason (e.g., decryption failure, restart, etc.)
-                // We should accept the new handshake to re-establish encryption
-                if existing.isEstablished() {
-                    SecureLogger.log("Accepting handshake from \(peerID) despite existing session - peer likely cleared their session", 
-                                   category: SecureLogger.session, level: .info)
-                    _ = sessions.removeValue(forKey: peerID)
-                    shouldCreateNew = true
-                } else {
-                    // If we're in the middle of a handshake and receive a new initiation,
-                    // reset and start fresh (the other side may have restarted)
-                    if existing.getState() == .handshaking && message.count == 32 {
-                        _ = sessions.removeValue(forKey: peerID)
-                        shouldCreateNew = true
-                    } else {
-                        existingSession = existing
-                    }
-                }
-            } else {
-                shouldCreateNew = true
-            }
-            
-            // Get or create session
-            let session: NoiseSession
-            if shouldCreateNew {
-                let newSession = SecureNoiseSession(
-                    peerID: peerID,
-                    role: .responder,
-                    localStaticKey: localStaticKey
-                )
-                sessions[peerID] = newSession
-                session = newSession
-            } else {
-                session = existingSession!
-            }
-            
-            // Process the handshake message within the synchronized block
-            do {
-                let response = try session.processHandshakeMessage(message)
-                
-                // Check if session is established after processing
-                if session.isEstablished() {
-                    if let remoteKey = session.getRemoteStaticPublicKey() {
-                        // Schedule callback outside the synchronized block to prevent deadlock
-                        DispatchQueue.global().async { [weak self] in
-                            self?.onSessionEstablished?(peerID, remoteKey)
-                        }
-                    }
-                }
-                
-                return response
-            } catch {
-                // Reset the session on handshake failure so next attempt can start fresh
-                _ = sessions.removeValue(forKey: peerID)
-                
-                // Schedule callback outside the synchronized block to prevent deadlock
-                DispatchQueue.global().async { [weak self] in
-                    self?.onSessionFailed?(peerID, error)
-                }
-                
-                SecureLogger.logSecurityEvent(.handshakeFailed(peerID: peerID, error: error.localizedDescription), level: .error)
-                throw error
-            }
-        }
-    }
-    
-    // MARK: - Encryption/Decryption
-    
-    func encrypt(_ plaintext: Data, for peerID: String) throws -> Data {
-        guard let session = getSession(for: peerID) else {
-            throw NoiseSessionError.sessionNotFound
-        }
-        
-        return try session.encrypt(plaintext)
-    }
-    
-    func decrypt(_ ciphertext: Data, from peerID: String) throws -> Data {
-        guard let session = getSession(for: peerID) else {
-            throw NoiseSessionError.sessionNotFound
-        }
-        
-        return try session.decrypt(ciphertext)
-    }
-    
-    // MARK: - Key Management
-    
-    func getRemoteStaticKey(for peerID: String) -> Curve25519.KeyAgreement.PublicKey? {
-        return getSession(for: peerID)?.getRemoteStaticPublicKey()
-    }
-    
-    func getHandshakeHash(for peerID: String) -> Data? {
-        return getSession(for: peerID)?.getHandshakeHash()
-    }
-    
-    // MARK: - Session Rekeying
-    
-    func getSessionsNeedingRekey() -> [(peerID: String, needsRekey: Bool)] {
-        return managerQueue.sync {
-            var needingRekey: [(peerID: String, needsRekey: Bool)] = []
-            
-            for (peerID, session) in sessions {
-                if let secureSession = session as? SecureNoiseSession,
-                   secureSession.isEstablished(),
-                   secureSession.needsRenegotiation() {
-                    needingRekey.append((peerID: peerID, needsRekey: true))
-                }
-            }
-            
-            return needingRekey
-        }
-    }
-    
-    func initiateRekey(for peerID: String) throws {
-        // Remove old session
-        removeSession(for: peerID)
-        
-        // Initiate new handshake
-        _ = try initiateHandshake(with: peerID)
-        
-    }
-}
-
-// MARK: - Errors
-
-enum NoiseSessionError: Error {
-    case invalidState
-    case notEstablished
-    case sessionNotFound
-    case handshakeFailed(Error)
-    case alreadyEstablished
-}

bitchat/Noise/NoiseSessionError.swift

@@ -0,0 +1,14 @@
+//
+// NoiseSessionError.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+enum NoiseSessionError: Error, Equatable {
+    case invalidState
+    case notEstablished
+    case sessionNotFound
+    case alreadyEstablished
+}

bitchat/Noise/NoiseSessionManager.swift

@@ -0,0 +1,223 @@
+//
+// NoiseSessionManager.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import BitLogger
+import CryptoKit
+import Foundation
+import BitFoundation
+
+final class NoiseSessionManager {
+    private var sessions: [PeerID: NoiseSession] = [:]
+    private let localStaticKey: Curve25519.KeyAgreement.PrivateKey
+    private let keychain: KeychainManagerProtocol
+    private let sessionFactory: (PeerID, NoiseRole) -> NoiseSession
+    private let managerQueue = DispatchQueue(label: "chat.bitchat.noise.manager", attributes: .concurrent)
+    
+    // Callbacks
+    var onSessionEstablished: ((PeerID, Curve25519.KeyAgreement.PublicKey) -> Void)?
+    var onSessionFailed: ((PeerID, Error) -> Void)?
+    
+    init(localStaticKey: Curve25519.KeyAgreement.PrivateKey, keychain: KeychainManagerProtocol) {
+        self.localStaticKey = localStaticKey
+        self.keychain = keychain
+        self.sessionFactory = { peerID, role in
+            SecureNoiseSession(
+                peerID: peerID,
+                role: role,
+                keychain: keychain,
+                localStaticKey: localStaticKey
+            )
+        }
+    }
+
+    #if DEBUG
+    init(
+        localStaticKey: Curve25519.KeyAgreement.PrivateKey,
+        keychain: KeychainManagerProtocol,
+        sessionFactory: @escaping (PeerID, NoiseRole) -> NoiseSession
+    ) {
+        self.localStaticKey = localStaticKey
+        self.keychain = keychain
+        self.sessionFactory = sessionFactory
+    }
+    #endif
+    
+    // MARK: - Session Management
+    
+    func getSession(for peerID: PeerID) -> NoiseSession? {
+        return managerQueue.sync {
+            return sessions[peerID]
+        }
+    }
+    
+    func removeSession(for peerID: PeerID) {
+        managerQueue.sync(flags: .barrier) {
+            if let session = sessions.removeValue(forKey: peerID) {
+                session.reset() // Clear sensitive data before removing
+            }
+        }
+    }
+
+    func removeAllSessions() {
+        managerQueue.sync(flags: .barrier) {
+            for (_, session) in sessions {
+                session.reset()
+            }
+            sessions.removeAll()
+        }
+    }
+    
+    // MARK: - Handshake Helpers
+    
+    func initiateHandshake(with peerID: PeerID) throws -> Data {
+        return try managerQueue.sync(flags: .barrier) {
+            // Check if we already have an established session
+            if let existingSession = sessions[peerID], existingSession.isEstablished() {
+                // Session already established, don't recreate
+                throw NoiseSessionError.alreadyEstablished
+            }
+            
+            // Remove any existing non-established session
+            if let existingSession = sessions[peerID], !existingSession.isEstablished() {
+                _ = sessions.removeValue(forKey: peerID)
+            }
+            
+            // Create new initiator session
+            let session = sessionFactory(peerID, .initiator)
+            sessions[peerID] = session
+            
+            do {
+                let handshakeData = try session.startHandshake()
+                return handshakeData
+            } catch {
+                // Clean up failed session
+                _ = sessions.removeValue(forKey: peerID)
+                SecureLogger.error(.handshakeFailed(peerID: peerID.id, error: error.localizedDescription))
+                throw error
+            }
+        }
+    }
+    
+    func handleIncomingHandshake(from peerID: PeerID, message: Data) throws -> Data? {
+        // Process everything within the synchronized block to prevent race conditions
+        return try managerQueue.sync(flags: .barrier) {
+            var shouldCreateNew = false
+            var existingSession: NoiseSession? = nil
+            
+            if let existing = sessions[peerID] {
+                // If we have an established session, the peer must have cleared their session
+                // for a good reason (e.g., decryption failure, restart, etc.)
+                // We should accept the new handshake to re-establish encryption
+                if existing.isEstablished() {
+                    SecureLogger.info("Accepting handshake from \(peerID) despite existing session - peer likely cleared their session", category: .session)
+                    _ = sessions.removeValue(forKey: peerID)
+                    shouldCreateNew = true
+                } else {
+                    // If we're in the middle of a handshake and receive a new initiation,
+                    // reset and start fresh (the other side may have restarted)
+                    if existing.getState() == .handshaking && message.count == 32 {
+                        _ = sessions.removeValue(forKey: peerID)
+                        shouldCreateNew = true
+                    } else {
+                        existingSession = existing
+                    }
+                }
+            } else {
+                shouldCreateNew = true
+            }
+            
+            // Get or create session
+            let session: NoiseSession
+            if shouldCreateNew {
+                let newSession = sessionFactory(peerID, .responder)
+                sessions[peerID] = newSession
+                session = newSession
+            } else {
+                session = existingSession!
+            }
+            
+            // Process the handshake message within the synchronized block
+            do {
+                let response = try session.processHandshakeMessage(message)
+                
+                // Check if session is established after processing
+                if session.isEstablished() {
+                    if let remoteKey = session.getRemoteStaticPublicKey() {
+                        // Schedule callback outside the synchronized block to prevent deadlock
+                        DispatchQueue.global().async { [weak self] in
+                            self?.onSessionEstablished?(peerID, remoteKey)
+                        }
+                    }
+                }
+                
+                return response
+            } catch {
+                // Reset the session on handshake failure so next attempt can start fresh
+                _ = sessions.removeValue(forKey: peerID)
+                
+                // Schedule callback outside the synchronized block to prevent deadlock
+                DispatchQueue.global().async { [weak self] in
+                    self?.onSessionFailed?(peerID, error)
+                }
+                
+                SecureLogger.error(.handshakeFailed(peerID: peerID.id, error: error.localizedDescription))
+                throw error
+            }
+        }
+    }
+    
+    // MARK: - Encryption/Decryption
+    
+    func encrypt(_ plaintext: Data, for peerID: PeerID) throws -> Data {
+        guard let session = getSession(for: peerID) else {
+            throw NoiseSessionError.sessionNotFound
+        }
+        
+        return try session.encrypt(plaintext)
+    }
+    
+    func decrypt(_ ciphertext: Data, from peerID: PeerID) throws -> Data {
+        guard let session = getSession(for: peerID) else {
+            throw NoiseSessionError.sessionNotFound
+        }
+        
+        return try session.decrypt(ciphertext)
+    }
+    
+    // MARK: - Key Management
+    
+    func getRemoteStaticKey(for peerID: PeerID) -> Curve25519.KeyAgreement.PublicKey? {
+        return getSession(for: peerID)?.getRemoteStaticPublicKey()
+    }
+    
+    // MARK: - Session Rekeying
+    
+    func getSessionsNeedingRekey() -> [(peerID: PeerID, needsRekey: Bool)] {
+        return managerQueue.sync {
+            var needingRekey: [(peerID: PeerID, needsRekey: Bool)] = []
+            
+            for (peerID, session) in sessions {
+                if let secureSession = session as? SecureNoiseSession,
+                   secureSession.isEstablished(),
+                   secureSession.needsRenegotiation() {
+                    needingRekey.append((peerID: peerID, needsRekey: true))
+                }
+            }
+            
+            return needingRekey
+        }
+    }
+    
+    func initiateRekey(for peerID: PeerID) throws {
+        // Remove old session
+        removeSession(for: peerID)
+        
+        // Initiate new handshake
+        _ = try initiateHandshake(with: peerID)
+    }
+}

bitchat/Noise/NoiseSessionState.swift

@@ -0,0 +1,13 @@
+//
+// NoiseSessionState.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+enum NoiseSessionState: Equatable {
+    case uninitialized
+    case handshaking
+    case established
+}

bitchat/Noise/SecureNoiseSession.swift

@@ -0,0 +1,85 @@
+//
+// SecureNoiseSession.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+
+final class SecureNoiseSession: NoiseSession {
+    private(set) var messageCount: UInt64 = 0
+    private var sessionStartTime = Date()
+    private(set) var lastActivityTime = Date()
+    
+    override func encrypt(_ plaintext: Data) throws -> Data {
+        // Check session age
+        if Date().timeIntervalSince(sessionStartTime) > NoiseSecurityConstants.sessionTimeout {
+            throw NoiseSecurityError.sessionExpired
+        }
+        
+        // Check message count
+        if messageCount >= NoiseSecurityConstants.maxMessagesPerSession {
+            throw NoiseSecurityError.sessionExhausted
+        }
+        
+        // Validate message size
+        guard NoiseSecurityValidator.validateMessageSize(plaintext) else {
+            throw NoiseSecurityError.messageTooLarge
+        }
+        
+        let encrypted = try super.encrypt(plaintext)
+        messageCount += 1
+        lastActivityTime = Date()
+        
+        return encrypted
+    }
+    
+    override func decrypt(_ ciphertext: Data) throws -> Data {
+        // Check session age
+        if Date().timeIntervalSince(sessionStartTime) > NoiseSecurityConstants.sessionTimeout {
+            throw NoiseSecurityError.sessionExpired
+        }
+        
+        // Validate message size
+        guard NoiseSecurityValidator.validateMessageSize(ciphertext) else {
+            throw NoiseSecurityError.messageTooLarge
+        }
+        
+        let decrypted = try super.decrypt(ciphertext)
+        lastActivityTime = Date()
+        
+        return decrypted
+    }
+    
+    func needsRenegotiation() -> Bool {
+        // Check if we've used more than 90% of message limit
+        let messageThreshold = UInt64(Double(NoiseSecurityConstants.maxMessagesPerSession) * 0.9)
+        if messageCount >= messageThreshold {
+            return true
+        }
+        
+        // Check if last activity was more than 30 minutes ago
+        if Date().timeIntervalSince(lastActivityTime) > NoiseSecurityConstants.sessionTimeout {
+            return true
+        }
+        
+        return false
+    }
+    
+    // MARK: - Testing Support
+    #if DEBUG
+    func setLastActivityTimeForTesting(_ date: Date) {
+        lastActivityTime = date
+    }
+    
+    func setMessageCountForTesting(_ count: UInt64) {
+        messageCount = count
+    }
+
+    func setSessionStartTimeForTesting(_ date: Date) {
+        sessionStartTime = date
+    }
+    #endif
+}

bitchat/Nostr/Base64URLCoding.swift

@@ -0,0 +1,22 @@
+import Foundation
+
+enum Base64URLCoding {
+    static func encode(_ data: Data) -> String {
+        data.base64EncodedString()
+            .replacingOccurrences(of: "+", with: "-")
+            .replacingOccurrences(of: "/", with: "_")
+            .replacingOccurrences(of: "=", with: "")
+    }
+
+    static func decode(_ string: String) -> Data? {
+        var base64 = string
+        let padding = (4 - (base64.count % 4)) % 4
+        if padding > 0 {
+            base64 += String(repeating: "=", count: padding)
+        }
+        base64 = base64
+            .replacingOccurrences(of: "-", with: "+")
+            .replacingOccurrences(of: "_", with: "/")
+        return Data(base64Encoded: base64)
+    }
+}

bitchat/Nostr/Bech32.swift

@@ -0,0 +1,135 @@
+import Foundation
+
+/// Bech32 encoding for Nostr (minimal implementation)
+enum Bech32 {
+    private static let charset = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
+    private static let generator = [0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3]
+    
+    static func encode(hrp: String, data: Data) throws -> String {
+        let values = convertBits(from: 8, to: 5, pad: true, data: Array(data))
+        let checksum = createChecksum(hrp: hrp, values: values)
+        let combined = values + checksum
+        
+        return hrp + "1" + combined.map { 
+            let index = charset.index(charset.startIndex, offsetBy: Int($0))
+            return String(charset[index])
+        }.joined()
+    }
+    
+    static func decode(_ bech32String: String) throws -> (hrp: String, data: Data) {
+        // Find the last occurrence of '1'
+        guard let separatorIndex = bech32String.lastIndex(of: "1") else {
+            throw Bech32Error.invalidFormat
+        }
+        
+        let hrp = String(bech32String[..<separatorIndex])
+        
+        // Validate HRP contains only ASCII characters
+        for char in hrp {
+            guard char.asciiValue != nil else {
+                throw Bech32Error.invalidCharacter
+            }
+        }
+        
+        let dataString = String(bech32String[bech32String.index(after: separatorIndex)...])
+        
+        // Convert characters to values
+        var values = [UInt8]()
+        for char in dataString {
+            guard let index = charset.firstIndex(of: char) else {
+                throw Bech32Error.invalidCharacter
+            }
+            values.append(UInt8(charset.distance(from: charset.startIndex, to: index)))
+        }
+        
+        // Verify checksum
+        guard values.count >= 6 else {
+            throw Bech32Error.invalidChecksum
+        }
+        
+        let payloadValues = Array(values.dropLast(6))
+        let checksum = Array(values.suffix(6))
+        let expectedChecksum = createChecksum(hrp: hrp, values: payloadValues)
+        
+        guard checksum == expectedChecksum else {
+            throw Bech32Error.invalidChecksum
+        }
+        
+        // Convert back to bytes
+        let bytes = convertBits(from: 5, to: 8, pad: false, data: payloadValues)
+        return (hrp: hrp, data: Data(bytes))
+    }
+    
+    enum Bech32Error: Error {
+        case invalidFormat
+        case invalidCharacter
+        case invalidChecksum
+    }
+    
+    private static func convertBits(from: Int, to: Int, pad: Bool, data: [UInt8]) -> [UInt8] {
+        var acc = 0
+        var bits = 0
+        var result = [UInt8]()
+        let maxv = (1 << to) - 1
+        
+        for value in data {
+            acc = (acc << from) | Int(value)
+            bits += from
+            
+            while bits >= to {
+                bits -= to
+                result.append(UInt8((acc >> bits) & maxv))
+            }
+        }
+        
+        if pad && bits > 0 {
+            result.append(UInt8((acc << (to - bits)) & maxv))
+        }
+        
+        return result
+    }
+    
+    private static func createChecksum(hrp: String, values: [UInt8]) -> [UInt8] {
+        let checksumValues = hrpExpand(hrp) + values + [0, 0, 0, 0, 0, 0]
+        let polymod = polymod(checksumValues) ^ 1
+        var checksum = [UInt8]()
+        
+        for i in 0..<6 {
+            checksum.append(UInt8((polymod >> (5 * (5 - i))) & 31))
+        }
+        
+        return checksum
+    }
+    
+    private static func hrpExpand(_ hrp: String) -> [UInt8] {
+        var result = [UInt8]()
+        for c in hrp {
+            guard let asciiValue = c.asciiValue else {
+                return [] // Return empty array for invalid input
+            }
+            result.append(UInt8(asciiValue >> 5))
+        }
+        result.append(0)
+        for c in hrp {
+            guard let asciiValue = c.asciiValue else {
+                return [] // Return empty array for invalid input
+            }
+            result.append(UInt8(asciiValue & 31))
+        }
+        return result
+    }
+    
+    private static func polymod(_ values: [UInt8]) -> Int {
+        var chk = 1
+        for value in values {
+            let b = chk >> 25
+            chk = (chk & 0x1ffffff) << 5 ^ Int(value)
+            for i in 0..<5 {
+                if (b >> i) & 1 == 1 {
+                    chk ^= generator[i]
+                }
+            }
+        }
+        return chk
+    }
+}

bitchat/Nostr/GeoRelayDirectory.swift

@@ -0,0 +1,440 @@
+import BitLogger
+import Foundation
+import Tor
+#if os(iOS)
+import UIKit
+#elseif os(macOS)
+import AppKit
+#endif
+
+extension Notification.Name {
+    /// Posted after the geo relay directory successfully refreshes its entries.
+    static let geoRelayDirectoryDidRefresh = Notification.Name("bitchat.geoRelayDirectoryDidRefresh")
+}
+
+/// Directory of online Nostr relays with approximate GPS locations, used for geohash routing.
+struct GeoRelayDirectoryDependencies {
+    var userDefaults: UserDefaults
+    var notificationCenter: NotificationCenter
+    var now: () -> Date
+    var remoteURL: URL
+    var fetchInterval: TimeInterval
+    var refreshCheckInterval: TimeInterval
+    var retryInitialSeconds: TimeInterval
+    var retryMaxSeconds: TimeInterval
+    var awaitTorReady: @Sendable () async -> Bool
+    var makeFetchData: @MainActor @Sendable () -> (@Sendable (URLRequest) async throws -> Data)
+    var readData: (URL) -> Data?
+    var writeData: (Data, URL) throws -> Void
+    var cacheURL: () -> URL?
+    var bundledCSVURLs: () -> [URL]
+    var currentDirectoryPath: () -> String?
+    var retrySleep: (TimeInterval) async -> Void
+    var activeNotificationName: Notification.Name?
+    var autoStart: Bool
+}
+
+private extension GeoRelayDirectoryDependencies {
+    @MainActor
+    static func live() -> Self {
+#if os(iOS)
+        let activeNotificationName: Notification.Name? = UIApplication.didBecomeActiveNotification
+#elseif os(macOS)
+        let activeNotificationName: Notification.Name? = NSApplication.didBecomeActiveNotification
+#else
+        let activeNotificationName: Notification.Name? = nil
+#endif
+
+        return Self(
+            userDefaults: .standard,
+            notificationCenter: .default,
+            now: Date.init,
+            remoteURL: URL(string: "https://raw.githubusercontent.com/permissionlesstech/georelays/refs/heads/main/nostr_relays.csv")!,
+            fetchInterval: TransportConfig.geoRelayFetchIntervalSeconds,
+            refreshCheckInterval: TransportConfig.geoRelayRefreshCheckIntervalSeconds,
+            retryInitialSeconds: TransportConfig.geoRelayRetryInitialSeconds,
+            retryMaxSeconds: TransportConfig.geoRelayRetryMaxSeconds,
+            awaitTorReady: { await TorManager.shared.awaitReady() },
+            makeFetchData: {
+                let session = TorURLSession.shared.session
+                return { request in
+                    let (data, _) = try await session.data(for: request)
+                    return data
+                }
+            },
+            readData: { try? Data(contentsOf: $0) },
+            writeData: { data, url in
+                try data.write(to: url, options: .atomic)
+            },
+            cacheURL: {
+                do {
+                    let base = try FileManager.default.url(
+                        for: .applicationSupportDirectory,
+                        in: .userDomainMask,
+                        appropriateFor: nil,
+                        create: true
+                    )
+                    let dir = base.appendingPathComponent("bitchat", isDirectory: true)
+                    try? FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+                    return dir.appendingPathComponent("georelays_cache.csv")
+                } catch {
+                    return nil
+                }
+            },
+            bundledCSVURLs: {
+                [
+                    Bundle.main.url(forResource: "nostr_relays", withExtension: "csv"),
+                    Bundle.main.url(forResource: "online_relays_gps", withExtension: "csv"),
+                    Bundle.main.url(forResource: "online_relays_gps", withExtension: "csv", subdirectory: "relays")
+                ].compactMap { $0 }
+            },
+            currentDirectoryPath: { FileManager.default.currentDirectoryPath },
+            retrySleep: { delay in
+                let nanoseconds = UInt64(delay * 1_000_000_000)
+                try? await Task.sleep(nanoseconds: nanoseconds)
+            },
+            activeNotificationName: activeNotificationName,
+            autoStart: true
+        )
+    }
+}
+
+@MainActor
+final class GeoRelayDirectory {
+    private final class CleanupState {
+        let notificationCenter: NotificationCenter
+        var observers: [NSObjectProtocol] = []
+        var refreshTimer: Timer?
+        var retryTask: Task<Void, Never>?
+
+        init(notificationCenter: NotificationCenter) {
+            self.notificationCenter = notificationCenter
+        }
+
+        deinit {
+            observers.forEach { notificationCenter.removeObserver($0) }
+            refreshTimer?.invalidate()
+            retryTask?.cancel()
+        }
+    }
+
+    struct Entry: Hashable, Sendable {
+        let host: String
+        let lat: Double
+        let lon: Double
+    }
+
+    private enum DetachedFetchOutcome: Sendable {
+        case success(entries: [Entry], csv: String)
+        case torNotReady
+        case invalidData
+        case network(String)
+    }
+
+    static let shared = GeoRelayDirectory()
+
+    private(set) var entries: [Entry] = []
+    private let lastFetchKey = "georelay.lastFetchAt"
+    private let dependencies: GeoRelayDirectoryDependencies
+    private let cleanupState: CleanupState
+
+    private var retryAttempt: Int = 0
+    private var isFetching: Bool = false
+
+    private init() {
+        self.dependencies = .live()
+        self.cleanupState = CleanupState(notificationCenter: dependencies.notificationCenter)
+        entries = loadLocalEntries()
+        if dependencies.autoStart {
+            registerObservers()
+            startRefreshTimer()
+            prefetchIfNeeded()
+        }
+    }
+
+    internal init(dependencies: GeoRelayDirectoryDependencies) {
+        self.dependencies = dependencies
+        self.cleanupState = CleanupState(notificationCenter: dependencies.notificationCenter)
+        entries = loadLocalEntries()
+        if dependencies.autoStart {
+            registerObservers()
+            startRefreshTimer()
+            prefetchIfNeeded()
+        }
+    }
+
+    /// Returns up to `count` relay URLs (wss://) closest to the geohash center.
+    func closestRelays(toGeohash geohash: String, count: Int = 5) -> [String] {
+        let center = Geohash.decodeCenter(geohash)
+        return closestRelays(toLat: center.lat, lon: center.lon, count: count)
+    }
+
+    /// Returns up to `count` relay URLs (wss://) closest to the given coordinate.
+    /// Ties break by host so every device with the same directory picks the
+    /// same relay set — publishers and subscribers must agree on relays.
+    func closestRelays(toLat lat: Double, lon: Double, count: Int = 5) -> [String] {
+        guard !entries.isEmpty, count > 0 else { return [] }
+
+        return entries
+            .map { (entry: $0, distance: haversineKm(lat, lon, $0.lat, $0.lon)) }
+            .sorted { ($0.distance, $0.entry.host) < ($1.distance, $1.entry.host) }
+            .prefix(count)
+            .map { "wss://\($0.entry.host)" }
+    }
+
+    // MARK: - Remote Fetch
+    func prefetchIfNeeded(force: Bool = false) {
+        guard !isFetching else { return }
+
+        let now = dependencies.now()
+        let last = dependencies.userDefaults.object(forKey: lastFetchKey) as? Date ?? .distantPast
+
+        if !force {
+            guard now.timeIntervalSince(last) >= dependencies.fetchInterval else { return }
+        } else if last != .distantPast,
+                  now.timeIntervalSince(last) < dependencies.retryInitialSeconds {
+            // Skip forced fetches if we just refreshed moments ago.
+            return
+        }
+
+        cancelRetry()
+        fetchRemote()
+    }
+
+    private func fetchRemote() {
+        guard !isFetching else { return }
+        isFetching = true
+
+        let request = URLRequest(
+            url: dependencies.remoteURL,
+            cachePolicy: .reloadIgnoringLocalCacheData,
+            timeoutInterval: 15
+        )
+        let awaitTorReady = dependencies.awaitTorReady
+        let fetchData = dependencies.makeFetchData()
+
+        Task { [weak self] in
+            guard let self else { return }
+
+            let outcome = await Self.fetchRemoteOutcome(
+                request: request,
+                awaitTorReady: awaitTorReady,
+                fetchData: fetchData
+            )
+
+            switch outcome {
+            case .success(let parsed, let csv):
+                self.handleFetchSuccess(entries: parsed, csv: csv)
+            case .torNotReady:
+                self.handleFetchFailure(.torNotReady)
+            case .invalidData:
+                self.handleFetchFailure(.invalidData)
+            case .network(let description):
+                self.handleFetchFailure(.network(description))
+            }
+        }
+    }
+
+    nonisolated private static func fetchRemoteOutcome(
+        request: URLRequest,
+        awaitTorReady: @escaping @Sendable () async -> Bool,
+        fetchData: @escaping @Sendable (URLRequest) async throws -> Data
+    ) async -> DetachedFetchOutcome {
+        await Task.detached(priority: .utility) {
+            let ready = await awaitTorReady()
+            guard ready else { return .torNotReady }
+
+            do {
+                let data = try await fetchData(request)
+                guard let text = String(data: data, encoding: .utf8) else {
+                    return .invalidData
+                }
+
+                let parsed = Self.parseCSV(text)
+                guard !parsed.isEmpty else {
+                    return .invalidData
+                }
+
+                return .success(entries: parsed, csv: text)
+            } catch {
+                return .network(error.localizedDescription)
+            }
+        }.value
+    }
+
+    private enum FetchFailure {
+        case torNotReady
+        case invalidData
+        case network(String)
+    }
+
+    @MainActor
+    private func handleFetchSuccess(entries parsed: [Entry], csv: String) {
+        entries = parsed
+        persistCache(csv)
+        dependencies.userDefaults.set(dependencies.now(), forKey: lastFetchKey)
+        SecureLogger.info("GeoRelayDirectory: refreshed \(parsed.count) relays from remote", category: .session)
+        isFetching = false
+        retryAttempt = 0
+        cancelRetry()
+        // Let waiters (e.g. location notes stuck in a "no relays" state) retry.
+        dependencies.notificationCenter.post(name: .geoRelayDirectoryDidRefresh, object: nil)
+    }
+
+    @MainActor
+    private func handleFetchFailure(_ reason: FetchFailure) {
+        switch reason {
+        case .torNotReady:
+            SecureLogger.warning("GeoRelayDirectory: Tor not ready; scheduling retry", category: .session)
+        case .invalidData:
+            SecureLogger.warning("GeoRelayDirectory: remote fetch returned invalid data; scheduling retry", category: .session)
+        case .network(let errorDescription):
+            SecureLogger.warning("GeoRelayDirectory: remote fetch failed with error: \(errorDescription)", category: .session)
+        }
+        isFetching = false
+        scheduleRetry()
+    }
+
+    @MainActor
+    private func scheduleRetry() {
+        retryAttempt = min(retryAttempt + 1, 10)
+        let base = dependencies.retryInitialSeconds
+        let maxDelay = dependencies.retryMaxSeconds
+        let multiplier = pow(2.0, Double(max(retryAttempt - 1, 0)))
+        let calculated = base * multiplier
+        let delay = min(maxDelay, max(base, calculated))
+
+        cancelRetry()
+        cleanupState.retryTask = Task { [weak self] in
+            guard let self else { return }
+            await self.dependencies.retrySleep(delay)
+            guard !Task.isCancelled else { return }
+            await MainActor.run {
+                self.prefetchIfNeeded(force: true)
+            }
+        }
+    }
+
+    @MainActor
+    private func cancelRetry() {
+        cleanupState.retryTask?.cancel()
+        cleanupState.retryTask = nil
+    }
+
+    private func persistCache(_ text: String) {
+        guard let url = dependencies.cacheURL() else { return }
+        guard let data = text.data(using: .utf8) else { return }
+        do {
+            try dependencies.writeData(data, url)
+        } catch {
+            SecureLogger.warning("GeoRelayDirectory: failed to write cache: \(error)", category: .session)
+        }
+    }
+
+    // MARK: - Loading
+    private func loadLocalEntries() -> [Entry] {
+        // Prefer cached file if present
+        if let cache = dependencies.cacheURL(),
+           let data = dependencies.readData(cache),
+           let text = String(data: data, encoding: .utf8) {
+            let arr = Self.parseCSV(text)
+            if !arr.isEmpty { return arr }
+        }
+
+        // Try bundled resource(s)
+        let bundleCandidates = dependencies.bundledCSVURLs()
+
+        for url in bundleCandidates {
+            if let data = dependencies.readData(url),
+               let text = String(data: data, encoding: .utf8) {
+                let arr = Self.parseCSV(text)
+                if !arr.isEmpty { return arr }
+            }
+        }
+
+        // Try filesystem path (development/test)
+        if let cwd = dependencies.currentDirectoryPath(),
+           let data = dependencies.readData(URL(fileURLWithPath: cwd).appendingPathComponent("relays/online_relays_gps.csv")),
+           let text = String(data: data, encoding: .utf8) {
+            return Self.parseCSV(text)
+        }
+
+        SecureLogger.warning("GeoRelayDirectory: no local CSV found; entries empty", category: .session)
+        return []
+    }
+
+    nonisolated static func parseCSV(_ text: String) -> [Entry] {
+        var result: Set<Entry> = []
+        let lines = text.split(whereSeparator: { $0.isNewline })
+        for (idx, raw) in lines.enumerated() {
+            guard let line = raw.trimmedOrNilIfEmpty else { continue }
+            if idx == 0 && line.lowercased().contains("relay url") { continue }
+            let parts = line.split(separator: ",").map { $0.trimmed }
+            guard parts.count >= 3 else { continue }
+            guard let host = NostrRelayURL.directoryAddress(parts[0]) else { continue }
+            guard let lat = Double(parts[1]), let lon = Double(parts[2]) else { continue }
+            result.insert(Entry(host: host, lat: lat, lon: lon))
+        }
+        return Array(result)
+    }
+
+    // MARK: - Observers & Timers
+    private func registerObservers() {
+        let center = dependencies.notificationCenter
+
+        let torReady = center.addObserver(
+            forName: .TorDidBecomeReady,
+            object: nil,
+            queue: .main
+        ) { [weak self] _ in
+            guard let self else { return }
+            Task { @MainActor in
+                self.prefetchIfNeeded(force: true)
+            }
+        }
+        cleanupState.observers.append(torReady)
+
+        if let activeNotificationName = dependencies.activeNotificationName {
+            let didBecomeActive = center.addObserver(
+                forName: activeNotificationName,
+                object: nil,
+                queue: .main
+            ) { [weak self] _ in
+                guard let self else { return }
+                Task { @MainActor in
+                    self.prefetchIfNeeded()
+                }
+            }
+            cleanupState.observers.append(didBecomeActive)
+        }
+    }
+
+    private func startRefreshTimer() {
+        cleanupState.refreshTimer?.invalidate()
+        let interval = dependencies.refreshCheckInterval
+        guard interval > 0 else { return }
+
+        let timer = Timer.scheduledTimer(withTimeInterval: interval, repeats: true) { [weak self] _ in
+            guard let self else { return }
+            Task { @MainActor in
+                self.prefetchIfNeeded()
+            }
+        }
+        cleanupState.refreshTimer = timer
+        RunLoop.main.add(timer, forMode: .common)
+    }
+
+    var debugRetryAttempt: Int { retryAttempt }
+    var debugHasRetryTask: Bool { cleanupState.retryTask != nil }
+    var debugObserverCount: Int { cleanupState.observers.count }
+}
+
+// MARK: - Distance
+private func haversineKm(_ lat1: Double, _ lon1: Double, _ lat2: Double, _ lon2: Double) -> Double {
+    let r = 6371.0 // Earth radius in km
+    let dLat = (lat2 - lat1) * .pi / 180
+    let dLon = (lon2 - lon1) * .pi / 180
+    let a = sin(dLat/2) * sin(dLat/2) + cos(lat1 * .pi/180) * cos(lat2 * .pi/180) * sin(dLon/2) * sin(dLon/2)
+    let c = 2 * atan2(sqrt(a), sqrt(1 - a))
+    return r * c
+}

bitchat/Nostr/NostrEmbeddedBitChat.swift

@@ -0,0 +1,122 @@
+import Foundation
+import BitFoundation
+
+// MARK: - BitChat-over-Nostr Adapter
+
+struct NostrEmbeddedBitChat {
+    /// Build a `bitchat1:` base64url-encoded BitChat packet carrying a private message for Nostr DMs.
+    static func encodePMForNostr(content: String, messageID: String, recipientPeerID: PeerID, senderPeerID: PeerID) -> String? {
+        // TLV-encode the private message
+        let pm = PrivateMessagePacket(messageID: messageID, content: content)
+        guard let tlv = pm.encode() else { return nil }
+
+        // Prefix with NoisePayloadType
+        var payload = Data([NoisePayloadType.privateMessage.rawValue])
+        payload.append(tlv)
+
+        // Determine 8-byte recipient ID to embed
+        let recipientID = normalizeRecipientPeerID(recipientPeerID)
+
+        let packet = BitchatPacket(
+            type: MessageType.noiseEncrypted.rawValue,
+            senderID: Data(hexString: senderPeerID.id) ?? Data(),
+            recipientID: Data(hexString: recipientID.id),
+            timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
+            payload: payload,
+            signature: nil,
+            ttl: 7
+        )
+
+        guard let data = packet.toBinaryData() else { return nil }
+        return "bitchat1:" + base64URLEncode(data)
+    }
+
+    /// Build a `bitchat1:` base64url-encoded BitChat packet carrying a delivery/read ack for Nostr DMs.
+    static func encodeAckForNostr(type: NoisePayloadType, messageID: String, recipientPeerID: PeerID, senderPeerID: PeerID) -> String? {
+        guard type == .delivered || type == .readReceipt else { return nil }
+
+        var payload = Data([type.rawValue])
+        payload.append(Data(messageID.utf8))
+
+        let recipientID = normalizeRecipientPeerID(recipientPeerID)
+
+        let packet = BitchatPacket(
+            type: MessageType.noiseEncrypted.rawValue,
+            senderID: Data(hexString: senderPeerID.id) ?? Data(),
+            recipientID: Data(hexString: recipientID.id),
+            timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
+            payload: payload,
+            signature: nil,
+            ttl: 7
+        )
+
+        guard let data = packet.toBinaryData() else { return nil }
+        return "bitchat1:" + base64URLEncode(data)
+    }
+
+    /// Build a `bitchat1:` ACK (delivered/read) without an embedded recipient peer ID (geohash DMs).
+    static func encodeAckForNostrNoRecipient(type: NoisePayloadType, messageID: String, senderPeerID: PeerID) -> String? {
+        guard type == .delivered || type == .readReceipt else { return nil }
+
+        var payload = Data([type.rawValue])
+        payload.append(Data(messageID.utf8))
+
+        let packet = BitchatPacket(
+            type: MessageType.noiseEncrypted.rawValue,
+            senderID: Data(hexString: senderPeerID.id) ?? Data(),
+            recipientID: nil,
+            timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
+            payload: payload,
+            signature: nil,
+            ttl: 7
+        )
+
+        guard let data = packet.toBinaryData() else { return nil }
+        return "bitchat1:" + base64URLEncode(data)
+    }
+
+    /// Build a `bitchat1:` payload without an embedded recipient peer ID (used for geohash DMs).
+    static func encodePMForNostrNoRecipient(content: String, messageID: String, senderPeerID: PeerID) -> String? {
+        let pm = PrivateMessagePacket(messageID: messageID, content: content)
+        guard let tlv = pm.encode() else { return nil }
+
+        var payload = Data([NoisePayloadType.privateMessage.rawValue])
+        payload.append(tlv)
+
+        let packet = BitchatPacket(
+            type: MessageType.noiseEncrypted.rawValue,
+            senderID: Data(hexString: senderPeerID.id) ?? Data(),
+            recipientID: nil,
+            timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
+            payload: payload,
+            signature: nil,
+            ttl: 7
+        )
+
+        guard let data = packet.toBinaryData() else { return nil }
+        return "bitchat1:" + base64URLEncode(data)
+    }
+
+    private static func normalizeRecipientPeerID(_ recipientPeerID: PeerID) -> PeerID {
+        if let maybeData = Data(hexString: recipientPeerID.id) {
+            if maybeData.count == 32 {
+                // Treat as Noise static public key; derive peerID from fingerprint
+                return PeerID(publicKey: maybeData)
+            } else if maybeData.count == 8 {
+                // Already an 8-byte peer ID
+                return recipientPeerID
+            }
+        }
+        // Fallback: return as-is (expecting 16 hex chars) – caller should pass a valid peer ID
+        return recipientPeerID
+    }
+
+    /// Base64url encode without padding
+    private static func base64URLEncode(_ data: Data) -> String {
+        let b64 = data.base64EncodedString()
+        return b64
+            .replacingOccurrences(of: "+", with: "-")
+            .replacingOccurrences(of: "/", with: "_")
+            .replacingOccurrences(of: "=", with: "")
+    }
+}

bitchat/Nostr/NostrIdentity.swift

@@ -1,47 +1,6 @@
 import Foundation
-import CryptoKit
 import P256K
 
-// Keychain helper for secure storage
-struct KeychainHelper {
-    static func save(key: String, data: Data, service: String) {
-        let query: [String: Any] = [
-            kSecClass as String: kSecClassGenericPassword,
-            kSecAttrService as String: service,
-            kSecAttrAccount as String: key,
-            kSecValueData as String: data
-        ]
-        
-        SecItemDelete(query as CFDictionary)
-        SecItemAdd(query as CFDictionary, nil)
-    }
-    
-    static func load(key: String, service: String) -> Data? {
-        let query: [String: Any] = [
-            kSecClass as String: kSecClassGenericPassword,
-            kSecAttrService as String: service,
-            kSecAttrAccount as String: key,
-            kSecReturnData as String: true
-        ]
-        
-        var result: AnyObject?
-        let status = SecItemCopyMatching(query as CFDictionary, &result)
-        
-        guard status == errSecSuccess else { return nil }
-        return result as? Data
-    }
-    
-    static func delete(key: String, service: String) {
-        let query: [String: Any] = [
-            kSecClass as String: kSecClassGenericPassword,
-            kSecAttrService as String: service,
-            kSecAttrAccount as String: key
-        ]
-        
-        SecItemDelete(query as CFDictionary)
-    }
-}
-
 /// Manages Nostr identity (secp256k1 keypair) for NIP-17 private messaging
 struct NostrIdentity: Codable {
     let privateKey: Data
@@ -99,167 +58,3 @@ struct NostrIdentity: Codable {
         return publicKey.hexEncodedString()
     }
 }
-
-/// Bridge between Noise and Nostr identities
-struct NostrIdentityBridge {
-    private static let keychainService = "chat.bitchat.nostr"
-    private static let currentIdentityKey = "nostr-current-identity"
-    
-    /// Get or create the current Nostr identity
-    static func getCurrentNostrIdentity() throws -> NostrIdentity? {
-        // Check if we already have a Nostr identity
-        if let existingData = KeychainHelper.load(key: currentIdentityKey, service: keychainService),
-           let identity = try? JSONDecoder().decode(NostrIdentity.self, from: existingData) {
-            return identity
-        }
-        
-        // Generate new Nostr identity
-        let nostrIdentity = try NostrIdentity.generate()
-        
-        // Store it
-        let data = try JSONEncoder().encode(nostrIdentity)
-        KeychainHelper.save(key: currentIdentityKey, data: data, service: keychainService)
-        
-        return nostrIdentity
-    }
-    
-    /// Associate a Nostr identity with a Noise public key (for favorites)
-    static func associateNostrIdentity(_ nostrPubkey: String, with noisePublicKey: Data) {
-        let key = "nostr-noise-\(noisePublicKey.base64EncodedString())"
-        if let data = nostrPubkey.data(using: .utf8) {
-            KeychainHelper.save(key: key, data: data, service: keychainService)
-        }
-    }
-    
-    /// Get Nostr public key associated with a Noise public key
-    static func getNostrPublicKey(for noisePublicKey: Data) -> String? {
-        let key = "nostr-noise-\(noisePublicKey.base64EncodedString())"
-        guard let data = KeychainHelper.load(key: key, service: keychainService),
-              let pubkey = String(data: data, encoding: .utf8) else {
-            return nil
-        }
-        return pubkey
-    }
-}
-
-// Bech32 encoding for Nostr (minimal implementation)
-enum Bech32 {
-    private static let charset = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
-    private static let generator = [0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3]
-    
-    static func encode(hrp: String, data: Data) throws -> String {
-        let values = convertBits(from: 8, to: 5, pad: true, data: Array(data))
-        let checksum = createChecksum(hrp: hrp, values: values)
-        let combined = values + checksum
-        
-        return hrp + "1" + combined.map { 
-            let index = charset.index(charset.startIndex, offsetBy: Int($0))
-            return String(charset[index])
-        }.joined()
-    }
-    
-    static func decode(_ bech32String: String) throws -> (hrp: String, data: Data) {
-        // Find the last occurrence of '1'
-        guard let separatorIndex = bech32String.lastIndex(of: "1") else {
-            throw Bech32Error.invalidFormat
-        }
-        
-        let hrp = String(bech32String[..<separatorIndex])
-        let dataString = String(bech32String[bech32String.index(after: separatorIndex)...])
-        
-        // Convert characters to values
-        var values = [UInt8]()
-        for char in dataString {
-            guard let index = charset.firstIndex(of: char) else {
-                throw Bech32Error.invalidCharacter
-            }
-            values.append(UInt8(charset.distance(from: charset.startIndex, to: index)))
-        }
-        
-        // Verify checksum
-        guard values.count >= 6 else {
-            throw Bech32Error.invalidChecksum
-        }
-        
-        let payloadValues = Array(values.dropLast(6))
-        let checksum = Array(values.suffix(6))
-        let expectedChecksum = createChecksum(hrp: hrp, values: payloadValues)
-        
-        guard checksum == expectedChecksum else {
-            throw Bech32Error.invalidChecksum
-        }
-        
-        // Convert back to bytes
-        let bytes = convertBits(from: 5, to: 8, pad: false, data: payloadValues)
-        return (hrp: hrp, data: Data(bytes))
-    }
-    
-    enum Bech32Error: Error {
-        case invalidFormat
-        case invalidCharacter
-        case invalidChecksum
-    }
-    
-    private static func convertBits(from: Int, to: Int, pad: Bool, data: [UInt8]) -> [UInt8] {
-        var acc = 0
-        var bits = 0
-        var result = [UInt8]()
-        let maxv = (1 << to) - 1
-        
-        for value in data {
-            acc = (acc << from) | Int(value)
-            bits += from
-            
-            while bits >= to {
-                bits -= to
-                result.append(UInt8((acc >> bits) & maxv))
-            }
-        }
-        
-        if pad && bits > 0 {
-            result.append(UInt8((acc << (to - bits)) & maxv))
-        }
-        
-        return result
-    }
-    
-    private static func createChecksum(hrp: String, values: [UInt8]) -> [UInt8] {
-        let checksumValues = hrpExpand(hrp) + values + [0, 0, 0, 0, 0, 0]
-        let polymod = polymod(checksumValues) ^ 1
-        var checksum = [UInt8]()
-        
-        for i in 0..<6 {
-            checksum.append(UInt8((polymod >> (5 * (5 - i))) & 31))
-        }
-        
-        return checksum
-    }
-    
-    private static func hrpExpand(_ hrp: String) -> [UInt8] {
-        var result = [UInt8]()
-        for c in hrp {
-            result.append(UInt8(c.asciiValue! >> 5))
-        }
-        result.append(0)
-        for c in hrp {
-            result.append(UInt8(c.asciiValue! & 31))
-        }
-        return result
-    }
-    
-    private static func polymod(_ values: [UInt8]) -> Int {
-        var chk = 1
-        for value in values {
-            let b = chk >> 25
-            chk = (chk & 0x1ffffff) << 5 ^ Int(value)
-            for i in 0..<5 {
-                if (b >> i) & 1 == 1 {
-                    chk ^= generator[i]
-                }
-            }
-        }
-        return chk
-    }
-}
-
-// Data hex encoding extension moved to BinaryEncodingUtils.swift to avoid duplication

bitchat/Nostr/NostrIdentityBridge.swift

@@ -0,0 +1,165 @@
+import BitFoundation
+import Foundation
+import CryptoKit
+
+/// Bridge between Noise and Nostr identities
+final class NostrIdentityBridge {
+    private let keychainService = "chat.bitchat.nostr"
+    private let currentIdentityKey = "nostr-current-identity"
+    private let deviceSeedKey = "nostr-device-seed"
+    // In-memory cache to avoid transient keychain access issues
+    private var deviceSeedCache: Data?
+    // Cache derived identities to avoid repeated crypto during view rendering
+    private var derivedIdentityCache: [String: NostrIdentity] = [:]
+    private let cacheLock = NSLock()
+
+    private let keychain: KeychainManagerProtocol
+
+    init(keychain: KeychainManagerProtocol = KeychainManager()) {
+        self.keychain = keychain
+    }
+    
+    /// Get or create the current Nostr identity
+    func getCurrentNostrIdentity() throws -> NostrIdentity? {
+        // Check if we already have a Nostr identity
+        if let existingData = keychain.load(key: currentIdentityKey, service: keychainService),
+           let identity = try? JSONDecoder().decode(NostrIdentity.self, from: existingData) {
+            return identity
+        }
+        
+        // Generate new Nostr identity
+        let nostrIdentity = try NostrIdentity.generate()
+        
+        // Store it
+        let data = try JSONEncoder().encode(nostrIdentity)
+        keychain.save(key: currentIdentityKey, data: data, service: keychainService, accessible: nil)
+        
+        return nostrIdentity
+    }
+    
+    /// Associate a Nostr identity with a Noise public key (for favorites)
+    func associateNostrIdentity(_ nostrPubkey: String, with noisePublicKey: Data) {
+        let key = "nostr-noise-\(noisePublicKey.base64EncodedString())"
+        if let data = nostrPubkey.data(using: .utf8) {
+            keychain.save(key: key, data: data, service: keychainService, accessible: nil)
+        }
+    }
+    
+    /// Get Nostr public key associated with a Noise public key
+    func getNostrPublicKey(for noisePublicKey: Data) -> String? {
+        let key = "nostr-noise-\(noisePublicKey.base64EncodedString())"
+        guard let data = keychain.load(key: key, service: keychainService),
+              let pubkey = String(data: data, encoding: .utf8) else {
+            return nil
+        }
+        return pubkey
+    }
+    
+    /// Clear all Nostr identity associations and current identity
+    func clearAllAssociations() {
+        let query: [String: Any] = [
+            kSecClass as String: kSecClassGenericPassword,
+            kSecAttrService as String: keychainService,
+            kSecMatchLimit as String: kSecMatchLimitAll,
+            kSecReturnAttributes as String: true
+        ]
+
+        var result: AnyObject?
+        let status = SecItemCopyMatching(query as CFDictionary, &result)
+        if status == errSecSuccess, let items = result as? [[String: Any]] {
+            for item in items {
+                var deleteQuery: [String: Any] = [
+                    kSecClass as String: kSecClassGenericPassword,
+                    kSecAttrService as String: keychainService
+                ]
+                if let account = item[kSecAttrAccount as String] as? String {
+                    deleteQuery[kSecAttrAccount as String] = account
+                }
+                SecItemDelete(deleteQuery as CFDictionary)
+            }
+        } else if status == errSecItemNotFound {
+            // nothing persisted; no action needed
+        }
+
+        deviceSeedCache = nil
+        // Also drop the in-memory derived per-geohash identities. These hold the
+        // actual secp256k1 private keys; if left cached, post-panic geohash
+        // messages would still be signed with pre-panic keys (linkable across the
+        // wipe) until the app is force-quit.
+        cacheLock.lock()
+        derivedIdentityCache.removeAll()
+        cacheLock.unlock()
+    }
+
+    // MARK: - Per-Geohash Identities (Location Channels)
+
+    /// Returns a stable device seed used to derive unlinkable per-geohash identities.
+    /// Stored only on device keychain.
+    private func getOrCreateDeviceSeed() -> Data {
+        if let cached = deviceSeedCache { return cached }
+        if let existing = keychain.load(key: deviceSeedKey, service: keychainService) {
+            // Migrate to AfterFirstUnlockThisDeviceOnly for stability during lock
+            keychain.save(key: deviceSeedKey, data: existing, service: keychainService, accessible: kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly)
+            deviceSeedCache = existing
+            return existing
+        }
+        var seed = Data(count: 32)
+        _ = seed.withUnsafeMutableBytes { ptr in
+            SecRandomCopyBytes(kSecRandomDefault, 32, ptr.baseAddress!)
+        }
+        // Ensure availability after first unlock to prevent unintended rotation when locked
+        keychain.save(key: deviceSeedKey, data: seed, service: keychainService, accessible: kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly)
+        deviceSeedCache = seed
+        return seed
+    }
+
+    /// Derive a deterministic, unlinkable Nostr identity for a given geohash.
+    /// Uses HMAC-SHA256(deviceSeed, geohash) as private key material, with fallback rehashing
+    /// if the candidate is not a valid secp256k1 private key.
+    func deriveIdentity(forGeohash geohash: String) throws -> NostrIdentity {
+        // Check cache first to avoid repeated crypto + keychain I/O during view rendering
+        cacheLock.lock()
+        if let cached = derivedIdentityCache[geohash] {
+            cacheLock.unlock()
+            return cached
+        }
+        cacheLock.unlock()
+
+        let seed = getOrCreateDeviceSeed()
+        guard let msg = geohash.data(using: .utf8) else {
+            throw NSError(domain: "NostrIdentity", code: -1, userInfo: [NSLocalizedDescriptionKey: "Invalid geohash string"])
+        }
+
+        func candidateKey(iteration: UInt32) -> Data {
+            var input = Data(msg)
+            var iterBE = iteration.bigEndian
+            withUnsafeBytes(of: &iterBE) { bytes in
+                input.append(contentsOf: bytes)
+            }
+            let code = HMAC<SHA256>.authenticationCode(for: input, using: SymmetricKey(data: seed))
+            return Data(code)
+        }
+
+        // Try a few iterations to ensure a valid key can be formed
+        for i in 0..<10 {
+            let keyData = candidateKey(iteration: UInt32(i))
+            if let identity = try? NostrIdentity(privateKeyData: keyData) {
+                // Cache the result
+                cacheLock.lock()
+                derivedIdentityCache[geohash] = identity
+                cacheLock.unlock()
+                return identity
+            }
+        }
+        // As a final fallback, hash the seed+msg and try again
+        let fallback = (seed + msg).sha256Hash()
+        let identity = try NostrIdentity(privateKeyData: fallback)
+
+        // Cache the result
+        cacheLock.lock()
+        derivedIdentityCache[geohash] = identity
+        cacheLock.unlock()
+
+        return identity
+    }
+}

bitchat/Nostr/NostrPoW.swift

@@ -0,0 +1,215 @@
+import BitFoundation
+import CryptoKit
+import Foundation
+
+/// NIP-13 proof-of-work for Nostr events.
+///
+/// Outgoing kind-20000 geohash messages mine a `["nonce", "<value>", "<target>"]`
+/// tag so the event ID carries at least `target` leading zero bits. Inbound
+/// events are scored (never hard-rejected — the network has clients that do
+/// not mine): validated PoW at or above `rateLimitBypassBits` relaxes the
+/// per-sender public rate limit, everything else keeps the strict limits.
+enum NostrPoW {
+
+    // MARK: - Tuning
+
+    /// Difficulty (leading zero bits of the event ID) mined onto outgoing
+    /// geohash messages. 8 bits is ~256 hash attempts — typically well under
+    /// 100 ms on any supported device.
+    static let targetBits = 8
+
+    /// Inbound events whose validated NIP-13 difficulty is at least this many
+    /// bits skip the per-sender rate-limit bucket (the content-flood bucket
+    /// still applies). See `MessageRateLimiter.allow`.
+    static let rateLimitBypassBits = 8
+
+    /// Hard cap on mining wall-clock time. When it hits, the committed target
+    /// steps down until a difficulty reachable in a small extra budget is
+    /// found and the message is sent anyway — mining never blocks sending.
+    static let miningTimeCap: TimeInterval = 2.0
+
+    /// Budget for each stepped-down attempt after the main cap (or a task
+    /// cancellation) hits.
+    private static let fallbackTimeCap: TimeInterval = 0.15
+
+    /// The hot loop checks the deadline and task cancellation every this many
+    /// hash attempts.
+    private static let checkInterval: UInt64 = 1024
+
+    /// The nonce value is a fixed-width hex counter so the serialized event
+    /// template can be mutated in place without reallocation.
+    private static let nonceLength = 16
+
+    // MARK: - Scoring
+
+    /// Number of leading zero bits in a byte sequence (NIP-13 difficulty of
+    /// an event-ID hash).
+    static func leadingZeroBits<Bytes: Sequence<UInt8>>(_ bytes: Bytes) -> Int {
+        var total = 0
+        for byte in bytes {
+            if byte == 0 {
+                total += 8
+            } else {
+                total += byte.leadingZeroBitCount
+                break
+            }
+        }
+        return total
+    }
+
+    /// Validated NIP-13 difficulty of an inbound event.
+    ///
+    /// The committed target in the nonce tag is what counts: the actual
+    /// leading zero bits of the ID must meet it (otherwise the claim is void
+    /// and the event scores 0), and work beyond the commitment earns no extra
+    /// credit — this stops spammers who mine a low target from getting lucky
+    /// high scores. Events without a well-formed commitment score 0.
+    static func validatedDifficulty(idHex: String, tags: [[String]]) -> Int {
+        guard let nonceTag = tags.last(where: { $0.first == "nonce" }),
+              nonceTag.count >= 3,
+              let committed = Int(nonceTag[2]),
+              committed > 0, committed <= 256,
+              let idData = Data(hexString: idHex)
+        else {
+            return 0
+        }
+        return leadingZeroBits(idData) >= committed ? committed : 0
+    }
+
+    // MARK: - Mining
+
+    /// Mine a `["nonce", value, target]` tag for the given unsigned-event
+    /// fields. Nonisolated async: runs off the calling actor.
+    ///
+    /// Bounded by `miningTimeCap`: when the cap hits — or the surrounding
+    /// task is cancelled — the committed target steps down (halving to 0,
+    /// which any hash satisfies) so the event still ships promptly with an
+    /// honest commitment at the difficulty actually reached. Returns nil only
+    /// if canonical serialization fails; the caller then sends unmined.
+    static func mineNonceTag(
+        pubkey: String,
+        createdAt: Int,
+        kind: Int,
+        tags: [[String]],
+        content: String,
+        targetBits: Int = NostrPoW.targetBits
+    ) async -> [String]? {
+        var target = min(max(targetBits, 0), 256)
+        var budget = miningTimeCap
+        while true {
+            if let tag = mineAttempt(
+                pubkey: pubkey,
+                createdAt: createdAt,
+                kind: kind,
+                baseTags: tags,
+                content: content,
+                targetBits: target,
+                budget: budget
+            ) {
+                return tag
+            }
+            // Target 0 succeeds on the first hash, so reaching it with nil
+            // means serialization itself failed — give up on mining.
+            if target == 0 { return nil }
+            target /= 2
+            budget = fallbackTimeCap
+        }
+    }
+
+    /// One bounded mining pass at a fixed committed target. Allocation-light:
+    /// the canonical serialization is built once and only the fixed-width
+    /// nonce bytes are rewritten per attempt (the event ID is recomputed for
+    /// every attempt, per NIP-13). Returns nil on timeout/cancellation or if
+    /// the template could not be built.
+    private static func mineAttempt(
+        pubkey: String,
+        createdAt: Int,
+        kind: Int,
+        baseTags: [[String]],
+        content: String,
+        targetBits: Int,
+        budget: TimeInterval
+    ) -> [String]? {
+        let targetString = String(targetBits)
+        guard let template = serializedTemplate(
+            pubkey: pubkey,
+            createdAt: createdAt,
+            kind: kind,
+            baseTags: baseTags,
+            content: content,
+            targetString: targetString
+        ) else {
+            return nil
+        }
+        var buffer = template.buffer
+        let nonceRange = template.nonceRange
+
+        let deadline = DispatchTime.now().uptimeNanoseconds &+ UInt64(budget * 1_000_000_000)
+        let hexDigits = [UInt8]("0123456789abcdef".utf8)
+        var nonce = UInt64.random(in: .min ... .max)
+        var attempts: UInt64 = 0
+
+        while true {
+            // Write the nonce as 16 lowercase hex chars, in place.
+            var value = nonce
+            var index = nonceRange.upperBound
+            while index > nonceRange.lowerBound {
+                index -= 1
+                buffer[index] = hexDigits[Int(value & 0xF)]
+                value >>= 4
+            }
+
+            if leadingZeroBits(SHA256.hash(data: buffer)) >= targetBits {
+                // Identical to the bytes just written into the buffer.
+                return ["nonce", String(format: "%016llx", nonce), targetString]
+            }
+
+            nonce &+= 1
+            attempts &+= 1
+            if attempts % checkInterval == 0,
+               Task.isCancelled || DispatchTime.now().uptimeNanoseconds >= deadline {
+                return nil
+            }
+        }
+    }
+
+    /// Canonical NIP-01 serialization of the event with a placeholder nonce,
+    /// plus the byte range of the nonce value inside it.
+    ///
+    /// The range is located by serializing twice with two same-length
+    /// placeholders and diffing the buffers — the only differing bytes are
+    /// the nonce value, so this stays correct however `JSONSerialization`
+    /// escapes the surrounding fields (and even if the content contains the
+    /// placeholder text itself).
+    private static func serializedTemplate(
+        pubkey: String,
+        createdAt: Int,
+        kind: Int,
+        baseTags: [[String]],
+        content: String,
+        targetString: String
+    ) -> (buffer: Data, nonceRange: Range<Int>)? {
+        func serialize(noncePlaceholder: String) -> Data? {
+            var tags = baseTags
+            tags.append(["nonce", noncePlaceholder, targetString])
+            let serialized: [Any] = [0, pubkey, createdAt, kind, tags, content]
+            return try? JSONSerialization.data(withJSONObject: serialized, options: [.withoutEscapingSlashes])
+        }
+
+        guard let zeros = serialize(noncePlaceholder: String(repeating: "0", count: nonceLength)),
+              let effs = serialize(noncePlaceholder: String(repeating: "f", count: nonceLength)),
+              zeros.count == effs.count
+        else {
+            return nil
+        }
+
+        var firstDiff = -1
+        var lastDiff = -1
+        for index in 0..<zeros.count where zeros[index] != effs[index] {
+            if firstDiff < 0 { firstDiff = index }
+            lastDiff = index
+        }
+        guard firstDiff >= 0, lastDiff - firstDiff + 1 == nonceLength else { return nil }
+        return (zeros, firstDiff..<(firstDiff + nonceLength))
+    }
+}

bitchat/Nostr/NostrProtocol.swift

@@ -1,6 +1,8 @@
+import BitLogger
 import Foundation
 import CryptoKit
 import P256K
+import Security
 
 // Note: This file depends on Data extension from BinaryEncodingUtils.swift
 // Make sure BinaryEncodingUtils.swift is included in the target
@@ -12,9 +14,11 @@ struct NostrProtocol {
     enum EventKind: Int {
         case metadata = 0
         case textNote = 1
+        case dm = 14 // NIP-17 DM rumor kind
         case seal = 13 // NIP-17 sealed event
-        case giftWrap = 1059 // NIP-17 gift wrap
+        case giftWrap = 1059 // NIP-59 gift wrap
         case ephemeralEvent = 20000
+        case geohashPresence = 20001
     }
     
     /// Create a NIP-17 private message
@@ -30,28 +34,28 @@ struct NostrProtocol {
         let rumor = NostrEvent(
             pubkey: senderIdentity.publicKeyHex,
             createdAt: Date(),
-            kind: .textNote,
+            kind: .dm, // NIP-17: DM rumor kind 14
             tags: [],
             content: content
         )
         
-        // 2. Create ephemeral key for this message
-        let ephemeralKey = try P256K.Schnorr.PrivateKey()
-        let _ = Data(ephemeralKey.xonly.bytes).hexEncodedString()
-        // Created ephemeral key for seal
-        
-        // 3. Seal the rumor (encrypt to recipient)
+        // 2. Seal the rumor (encrypt to recipient) and sign it with the SENDER'S
+        //    real identity key. NIP-17 requires the seal be signed by the sender
+        //    so the recipient can authenticate who sent the message; signing with
+        //    a throwaway key leaves DMs forgeable/impersonatable.
+        let senderKey = try senderIdentity.schnorrSigningKey()
         let sealedEvent = try createSeal(
             rumor: rumor,
             recipientPubkey: recipientPubkey,
-            senderKey: ephemeralKey
+            senderKey: senderKey
         )
-        
-        // 4. Gift wrap the sealed event (encrypt to recipient again)
+
+        // 3. Gift wrap the sealed event with a throwaway ephemeral key (the wrap
+        //    layer hides the sender's identity from relays; createGiftWrap mints
+        //    its own ephemeral key internally).
         let giftWrap = try createGiftWrap(
             seal: sealedEvent,
-            recipientPubkey: recipientPubkey,
-            senderKey: ephemeralKey
+            recipientPubkey: recipientPubkey
         )
         
         // Created gift wrap
@@ -60,10 +64,11 @@ struct NostrProtocol {
     }
     
     /// Decrypt a received NIP-17 message
+    /// Returns the content, sender pubkey, and the actual message timestamp (not the randomized gift wrap timestamp)
     static func decryptPrivateMessage(
         giftWrap: NostrEvent,
         recipientIdentity: NostrIdentity
-    ) throws -> (content: String, senderPubkey: String) {
+    ) throws -> (content: String, senderPubkey: String, timestamp: Int) {
         
         // Starting decryption
         
@@ -76,12 +81,19 @@ struct NostrProtocol {
             )
             // Successfully unwrapped gift wrap
         } catch {
-            SecureLogger.log("❌ Failed to unwrap gift wrap: \(error)", 
-                            category: SecureLogger.session, level: .error)
+            SecureLogger.error("❌ Failed to unwrap gift wrap: \(error)", category: .session)
             throw error
         }
         
-        // 2. Open the seal
+        // 2. Authenticate the seal. The seal MUST be signed by the sender's real
+        //    identity key (NIP-17); without this check a DM is forgeable by anyone
+        //    who knows the recipient's npub. Verify the seal's own signature.
+        guard seal.isValidSignature() else {
+            SecureLogger.error("❌ Rejecting DM: seal signature is missing or invalid", category: .session)
+            throw NostrError.invalidEvent
+        }
+
+        // 3. Open the seal
         let rumor: NostrEvent
         do {
             rumor = try openSeal(
@@ -90,12 +102,179 @@ struct NostrProtocol {
             )
             // Successfully opened seal
         } catch {
-            SecureLogger.log("❌ Failed to open seal: \(error)", 
-                            category: SecureLogger.session, level: .error)
+            SecureLogger.error("❌ Failed to open seal: \(error)", category: .session)
             throw error
         }
-        
-        return (content: rumor.content, senderPubkey: rumor.pubkey)
+
+        // 4. The sender claimed inside the rumor must match the key that actually
+        //    signed the seal, otherwise the sender field is unauthenticated and
+        //    spoofable.
+        guard seal.pubkey == rumor.pubkey else {
+            SecureLogger.error("❌ Rejecting DM: rumor pubkey does not match seal signer", category: .session)
+            throw NostrError.invalidEvent
+        }
+
+        // Return the seal signer's pubkey as the authenticated sender.
+        return (content: rumor.content, senderPubkey: seal.pubkey, timestamp: rumor.created_at)
+    }
+
+    #if DEBUG
+    static func createPrivateMessageWithInvalidSealSignatureForTesting(
+        content: String,
+        recipientPubkey: String,
+        senderIdentity: NostrIdentity
+    ) throws -> NostrEvent {
+        let rumor = NostrEvent(
+            pubkey: senderIdentity.publicKeyHex,
+            createdAt: Date(),
+            kind: .dm,
+            tags: [],
+            content: content
+        )
+        var seal = try createSeal(
+            rumor: rumor,
+            recipientPubkey: recipientPubkey,
+            senderKey: senderIdentity.schnorrSigningKey()
+        )
+        seal.sig = String(repeating: "0", count: 128)
+        return try createGiftWrap(seal: seal, recipientPubkey: recipientPubkey)
+    }
+
+    static func createPrivateMessageWithMismatchedSealRumorPubkeyForTesting(
+        content: String,
+        recipientPubkey: String,
+        rumorIdentity: NostrIdentity,
+        sealSignerIdentity: NostrIdentity
+    ) throws -> NostrEvent {
+        let rumor = NostrEvent(
+            pubkey: rumorIdentity.publicKeyHex,
+            createdAt: Date(),
+            kind: .dm,
+            tags: [],
+            content: content
+        )
+        let seal = try createSeal(
+            rumor: rumor,
+            recipientPubkey: recipientPubkey,
+            senderKey: sealSignerIdentity.schnorrSigningKey()
+        )
+        return try createGiftWrap(seal: seal, recipientPubkey: recipientPubkey)
+    }
+    #endif
+
+    /// Create a geohash-scoped ephemeral public message (kind 20000)
+    static func createEphemeralGeohashEvent(
+        content: String,
+        geohash: String,
+        senderIdentity: NostrIdentity,
+        nickname: String? = nil,
+        teleported: Bool = false
+    ) throws -> NostrEvent {
+        let event = NostrEvent(
+            pubkey: senderIdentity.publicKeyHex,
+            createdAt: Date(),
+            kind: .ephemeralEvent,
+            tags: ephemeralGeohashTags(geohash: geohash, nickname: nickname, teleported: teleported),
+            content: content
+        )
+        let schnorrKey = try senderIdentity.schnorrSigningKey()
+        return try event.sign(with: schnorrKey)
+    }
+
+    /// Create a kind-20000 geohash message carrying a NIP-13 proof-of-work
+    /// nonce tag (see `NostrPoW`). Mining runs off the calling actor and is
+    /// bounded by `NostrPoW.miningTimeCap`; when the cap hits (or the
+    /// surrounding task is cancelled) the event ships at the highest
+    /// committed difficulty still met, and if mining is impossible it ships
+    /// unmined — sending is never blocked.
+    static func createMinedEphemeralGeohashEvent(
+        content: String,
+        geohash: String,
+        senderIdentity: NostrIdentity,
+        nickname: String? = nil,
+        teleported: Bool = false,
+        powTargetBits: Int = NostrPoW.targetBits
+    ) async throws -> NostrEvent {
+        var tags = ephemeralGeohashTags(geohash: geohash, nickname: nickname, teleported: teleported)
+        // Fix created_at up front: the mined nonce commits to the full
+        // serialized event, so the signed event must reuse the exact value.
+        let createdAt = Int(Date().timeIntervalSince1970)
+        if let nonceTag = await NostrPoW.mineNonceTag(
+            pubkey: senderIdentity.publicKeyHex,
+            createdAt: createdAt,
+            kind: EventKind.ephemeralEvent.rawValue,
+            tags: tags,
+            content: content,
+            targetBits: powTargetBits
+        ) {
+            tags.append(nonceTag)
+        }
+        let event = NostrEvent(
+            pubkey: senderIdentity.publicKeyHex,
+            createdAt: Date(timeIntervalSince1970: TimeInterval(createdAt)),
+            kind: .ephemeralEvent,
+            tags: tags,
+            content: content
+        )
+        let schnorrKey = try senderIdentity.schnorrSigningKey()
+        return try event.sign(with: schnorrKey)
+    }
+
+    /// Tags for a kind-20000 geohash message (shared by the plain and mined
+    /// variants).
+    private static func ephemeralGeohashTags(
+        geohash: String,
+        nickname: String?,
+        teleported: Bool
+    ) -> [[String]] {
+        var tags = [["g", geohash]]
+        if let nickname = nickname?.trimmedOrNilIfEmpty {
+            tags.append(["n", nickname])
+        }
+        if teleported {
+            tags.append(["t", "teleport"])
+        }
+        return tags
+    }
+
+    /// Create a geohash presence heartbeat (kind 20001)
+    /// Must contain empty content and NO nickname tag
+    static func createGeohashPresenceEvent(
+        geohash: String,
+        senderIdentity: NostrIdentity
+    ) throws -> NostrEvent {
+        let tags = [["g", geohash]]
+        let event = NostrEvent(
+            pubkey: senderIdentity.publicKeyHex,
+            createdAt: Date(),
+            kind: .geohashPresence,
+            tags: tags,
+            content: ""
+        )
+        let schnorrKey = try senderIdentity.schnorrSigningKey()
+        return try event.sign(with: schnorrKey)
+    }
+
+    /// Create a persistent location note (kind 1: text note) tagged to a street-level geohash.
+    static func createGeohashTextNote(
+        content: String,
+        geohash: String,
+        senderIdentity: NostrIdentity,
+        nickname: String? = nil
+    ) throws -> NostrEvent {
+        var tags = [["g", geohash]]
+        if let nickname = nickname?.trimmedOrNilIfEmpty {
+            tags.append(["n", nickname])
+        }
+        let event = NostrEvent(
+            pubkey: senderIdentity.publicKeyHex,
+            createdAt: Date(),
+            kind: .textNote,
+            tags: tags,
+            content: content
+        )
+        let schnorrKey = try senderIdentity.schnorrSigningKey()
+        return try event.sign(with: schnorrKey)
     }
     
     // MARK: - Private Methods
@@ -121,17 +300,15 @@ struct NostrProtocol {
             content: encrypted
         )
         
-        // Convert to P256K.Signing.PrivateKey for signing (temporary until we update sign method)
-        let signingKey = try P256K.Signing.PrivateKey(dataRepresentation: senderKey.dataRepresentation)
-        return try seal.sign(with: signingKey)
+        // Sign the seal with the sender's Schnorr private key
+        return try seal.sign(with: senderKey)
     }
     
     private static func createGiftWrap(
         seal: NostrEvent,
-        recipientPubkey: String,
-        senderKey: P256K.Schnorr.PrivateKey  // This is the ephemeral key used for the seal
+        recipientPubkey: String
     ) throws -> NostrEvent {
-        
+
         let sealJSON = try seal.jsonString()
         
         // Create new ephemeral key for gift wrap
@@ -153,9 +330,8 @@ struct NostrProtocol {
             content: encrypted
         )
         
-        // Convert to P256K.Signing.PrivateKey for signing (temporary until we update sign method)
-        let signingKey = try P256K.Signing.PrivateKey(dataRepresentation: wrapKey.dataRepresentation)
-        return try giftWrap.sign(with: signingKey)
+        // Sign the gift wrap with the wrap Schnorr private key
+        return try giftWrap.sign(with: wrapKey)
     }
     
     private static func unwrapGiftWrap(
@@ -201,7 +377,7 @@ struct NostrProtocol {
         return try NostrEvent(from: rumorDict)
     }
     
-    // MARK: - Encryption (NIP-44 style)
+    // MARK: - Encryption (NIP-44 v2)
     
     private static func encrypt(
         plaintext: String,
@@ -213,34 +389,31 @@ struct NostrProtocol {
             throw NostrError.invalidPublicKey
         }
         
-        let _ = Data(senderKey.xonly.bytes).hexEncodedString()
-        // Encrypting message
+        // Encrypting message (NIP-44 v2: XChaCha20-Poly1305, versioned)
         
         // Derive shared secret
         let sharedSecret = try deriveSharedSecret(
             privateKey: senderKey,
             publicKey: recipientPubkeyData
         )
+        // Derive NIP-44 v2 symmetric key (HKDF-SHA256 with label in info)
+        let key = try deriveNIP44V2Key(from: sharedSecret)
         
-        // Derived shared secret
+        // 24-byte random nonce for XChaCha20-Poly1305
+        var nonce24 = Data(count: 24)
+        _ = nonce24.withUnsafeMutableBytes { ptr in
+            SecRandomCopyBytes(kSecRandomDefault, 24, ptr.baseAddress!)
+        }
         
-        // Generate nonce
-        let nonce = AES.GCM.Nonce()
+        let pt = Data(plaintext.utf8)
+        let sealed = try XChaCha20Poly1305Compat.seal(plaintext: pt, key: key, nonce24: nonce24)
         
-        // Encrypt
-        let sealed = try AES.GCM.seal(
-            plaintext.data(using: .utf8)!,
-            using: SymmetricKey(data: sharedSecret),
-            nonce: nonce
-        )
-        
-        // Combine nonce + ciphertext + tag
-        var result = Data()
-        result.append(nonce.withUnsafeBytes { Data($0) })
-        result.append(sealed.ciphertext)
-        result.append(sealed.tag)
-        
-        return result.base64EncodedString()
+        // v2: base64url(nonce24 || ciphertext || tag)
+        var combined = Data()
+        combined.append(nonce24)
+        combined.append(sealed.ciphertext)
+        combined.append(sealed.tag)
+        return "v2:" + Base64URLCoding.encode(combined)
     }
     
     private static func decrypt(
@@ -248,86 +421,45 @@ struct NostrProtocol {
         senderPubkey: String,
         recipientKey: P256K.Schnorr.PrivateKey
     ) throws -> String {
-        
-        // Decrypting message
-        
-        guard let data = Data(base64Encoded: ciphertext),
+        // Expect NIP-44 v2 format
+        guard ciphertext.hasPrefix("v2:") else { throw NostrError.invalidCiphertext }
+        let encoded = String(ciphertext.dropFirst(3))
+        guard let data = Base64URLCoding.decode(encoded),
+              data.count > (24 + 16),
               let senderPubkeyData = Data(hexString: senderPubkey) else {
-            SecureLogger.log("❌ Invalid ciphertext or sender pubkey format", 
-                            category: SecureLogger.session, level: .error)
             throw NostrError.invalidCiphertext
         }
-        
-        // Ciphertext data parsed
-        
-        // Extract components
-        let nonceData = data.prefix(12)
-        let ciphertextData = data.dropFirst(12).dropLast(16)
-        let tagData = data.suffix(16)
-        
-        // Components parsed
-        
-        // Derive shared secret - try with default Y coordinate first
-        var sharedSecret: Data
-        var decrypted: Data? = nil
-        
-        do {
-            sharedSecret = try deriveSharedSecret(
-                privateKey: recipientKey,
-                publicKey: senderPubkeyData
+
+        let nonce24 = data.prefix(24)
+        let rest = data.dropFirst(24)
+        let tag = rest.suffix(16)
+        let ct = rest.dropLast(16)
+
+        // Try decryption with even-Y then odd-Y when sender pubkey is x-only
+        func attemptDecrypt(using pubKeyData: Data) throws -> Data {
+            let ss = try deriveSharedSecret(privateKey: recipientKey, publicKey: pubKeyData)
+            let key = try deriveNIP44V2Key(from: ss)
+            return try XChaCha20Poly1305Compat.open(
+                ciphertext: Data(ct),
+                tag: Data(tag),
+                key: key,
+                nonce24: Data(nonce24)
             )
-            // Derived shared secret with first Y coordinate
-            
-            // Try to decrypt
-            let sealedBox = try AES.GCM.SealedBox(
-                nonce: AES.GCM.Nonce(data: nonceData),
-                ciphertext: ciphertextData,
-                tag: tagData
-            )
-            
-            do {
-                decrypted = try AES.GCM.open(
-                    sealedBox,
-                    using: SymmetricKey(data: sharedSecret)
-                )
-                // AES-GCM decryption successful
-            } catch {
-                // AES-GCM decryption failed, trying alternate
-                
-                // If the sender pubkey is x-only (32 bytes), try the other Y coordinate
-                if senderPubkeyData.count == 32 {
-                    // Trying alternate Y coordinate
-                    
-                    // Force deriveSharedSecret to use odd Y by manipulating the data
-                    var altPubkey = Data()
-                    altPubkey.append(0x03) // Force odd Y
-                    altPubkey.append(senderPubkeyData)
-                    
-                    sharedSecret = try deriveSharedSecretDirect(
-                        privateKey: recipientKey,
-                        publicKey: altPubkey
-                    )
-                    
-                    decrypted = try AES.GCM.open(
-                        sealedBox,
-                        using: SymmetricKey(data: sharedSecret)
-                    )
-                    // AES-GCM decryption successful with alternate Y
-                } else {
-                    throw error
-                }
+        }
+
+        // If 32 bytes (x-only) try both parities, otherwise single try
+        if senderPubkeyData.count == 32 {
+            let even = Data([0x02]) + senderPubkeyData
+            if let pt = try? attemptDecrypt(using: even) {
+                return String(data: pt, encoding: .utf8) ?? ""
             }
-        } catch {
-            SecureLogger.log("❌ Failed to derive shared secret or decrypt: \(error)", 
-                            category: SecureLogger.session, level: .error)
-            throw error
+            let odd = Data([0x03]) + senderPubkeyData
+            let pt = try attemptDecrypt(using: odd)
+            return String(data: pt, encoding: .utf8) ?? ""
+        } else {
+            let pt = try attemptDecrypt(using: senderPubkeyData)
+            return String(data: pt, encoding: .utf8) ?? ""
         }
-        
-        guard let finalDecrypted = decrypted else {
-            throw NostrError.encryptionFailed
-        }
-        
-        return String(data: finalDecrypted, encoding: .utf8) ?? ""
     }
     
     private static func deriveSharedSecret(
@@ -387,17 +519,8 @@ struct NostrProtocol {
         let sharedSecretData = sharedSecret.withUnsafeBytes { Data($0) }
         // ECDH shared secret derived
         
-        // Derive key using HKDF for NIP-44 v2
-        let derivedKey = HKDF<CryptoKit.SHA256>.deriveKey(
-            inputKeyMaterial: SymmetricKey(data: sharedSecretData),
-            salt: "nip44-v2".data(using: .utf8)!,
-            info: Data(),
-            outputByteCount: 32
-        )
-        
-        let result = derivedKey.withUnsafeBytes { Data($0) }
-        // Final derived key ready
-        return result
+        // Return raw ECDH shared secret; HKDF is applied by deriveNIP44V2Key
+        return sharedSecretData
     }
     
     // Direct version that doesn't try to add prefixes
@@ -427,34 +550,25 @@ struct NostrProtocol {
         // Convert SharedSecret to Data
         let sharedSecretData = sharedSecret.withUnsafeBytes { Data($0) }
         
-        // Derive key using HKDF for NIP-44 v2
-        let derivedKey = HKDF<CryptoKit.SHA256>.deriveKey(
-            inputKeyMaterial: SymmetricKey(data: sharedSecretData),
-            salt: "nip44-v2".data(using: .utf8)!,
-            info: Data(),
-            outputByteCount: 32
-        )
-        
-        return derivedKey.withUnsafeBytes { Data($0) }
+        // Return raw ECDH shared secret; HKDF is applied by deriveNIP44V2Key
+        return sharedSecretData
     }
     
     private static func randomizedTimestamp() -> Date {
         // Add random offset to current time for privacy
-        // TEMPORARY: Reduced range to debug timestamp issue
-        let offset = TimeInterval.random(in: -60...60) // +/- 1 minute (was +/- 15 minutes)
+        // This prevents timing correlation attacks while the actual message timestamp
+        // is preserved in the encrypted rumor
+        let offset = TimeInterval.random(in: -900...900) // +/- 15 minutes
         let now = Date()
         let randomized = now.addingTimeInterval(offset)
         
         // Log with explicit UTC and local time for debugging
         let formatter = DateFormatter()
+        //
         formatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
         formatter.timeZone = TimeZone(abbreviation: "UTC")
-        let _ = formatter.string(from: now)
-        let _ = formatter.string(from: randomized)
         
         formatter.timeZone = TimeZone.current
-        let _ = formatter.string(from: now)
-        let _ = formatter.string(from: randomized)
         
         // Timestamp randomized for privacy
         
@@ -506,16 +620,16 @@ struct NostrEvent: Codable {
         self.sig = dict["sig"] as? String
     }
     
-    func sign(with key: P256K.Signing.PrivateKey) throws -> NostrEvent {
+    func sign(with key: P256K.Schnorr.PrivateKey) throws -> NostrEvent {
         let (eventId, eventIdHash) = try calculateEventId()
         
-        // Convert to Schnorr key for Nostr signing
-        let schnorrKey = try P256K.Schnorr.PrivateKey(dataRepresentation: key.dataRepresentation)
-        
-        // Sign with Schnorr
+        // Sign with Schnorr (BIP-340)
         var messageBytes = [UInt8](eventIdHash)
-        var auxRand = [UInt8](repeating: 0, count: 32) // Zero auxiliary randomness for deterministic signing
-        let schnorrSignature = try schnorrKey.signature(message: &messageBytes, auxiliaryRand: &auxRand)
+        var auxRand = [UInt8](repeating: 0, count: 32)
+        _ = auxRand.withUnsafeMutableBytes { ptr in
+            SecRandomCopyBytes(kSecRandomDefault, 32, ptr.baseAddress!)
+        }
+        let schnorrSignature = try key.signature(message: &messageBytes, auxiliaryRand: &auxRand)
         
         let signatureHex = schnorrSignature.dataRepresentation.hexEncodedString()
         
@@ -524,6 +638,26 @@ struct NostrEvent: Codable {
         signed.sig = signatureHex
         return signed
     }
+
+    /// Validate that the event ID and Schnorr signature match the content and pubkey.
+    /// Returns false when the signature is missing, malformed, or does not verify.
+    func isValidSignature() -> Bool {
+        guard let sig = sig,
+              let sigData = Data(hexString: sig),
+              let pubData = Data(hexString: pubkey),
+              sigData.count == 64,
+              pubData.count == 32,
+              let signature = try? P256K.Schnorr.SchnorrSignature(dataRepresentation: sigData),
+              let (expectedId, eventHash) = try? calculateEventId(),
+              expectedId == id
+        else {
+            return false
+        }
+
+        var messageBytes = [UInt8](eventHash)
+        let xonly = P256K.Schnorr.XonlyKey(dataRepresentation: pubData)
+        return xonly.isValid(signature, for: &messageBytes)
+    }
     
     private func calculateEventId() throws -> (String, Data) {
         let serialized = [
@@ -536,10 +670,7 @@ struct NostrEvent: Codable {
         ] as [Any]
         
         let data = try JSONSerialization.data(withJSONObject: serialized, options: [.withoutEscapingSlashes])
-        let hash = CryptoKit.SHA256.hash(data: data)
-        let hashData = Data(hash)
-        let hashHex = hash.compactMap { String(format: "%02x", $0) }.joined()
-        return (hashHex, hashData)
+        return (data.sha256Fingerprint(), data.sha256Hash())
     }
     
     func jsonString() throws -> String {
@@ -557,4 +688,18 @@ enum NostrError: Error {
     case invalidCiphertext
     case signingFailed
     case encryptionFailed
-}
+}
+
+// MARK: - NIP-44 v2 helpers (XChaCha20-Poly1305)
+
+private extension NostrProtocol {
+    static func deriveNIP44V2Key(from sharedSecretData: Data) throws -> Data {
+        let derivedKey = HKDF<CryptoKit.SHA256>.deriveKey(
+            inputKeyMaterial: SymmetricKey(data: sharedSecretData),
+            salt: Data(),
+            info: Data("nip44-v2".utf8),
+            outputByteCount: 32
+        )
+        return derivedKey.withUnsafeBytes { Data($0) }
+    }
+}

bitchat/Nostr/NostrRelayURL.swift

@@ -0,0 +1,51 @@
+import Foundation
+
+enum NostrRelayURL {
+    static func normalized(_ rawValue: String, defaultScheme: String? = nil) -> String? {
+        var value = rawValue.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard !value.isEmpty else { return nil }
+
+        if !value.contains("://"), let defaultScheme {
+            value = "\(defaultScheme)://\(value)"
+        }
+
+        guard var components = URLComponents(string: value),
+              let rawScheme = components.scheme?.lowercased(),
+              let rawHost = components.host?.lowercased(),
+              !rawHost.isEmpty else {
+            return nil
+        }
+
+        switch rawScheme {
+        case "wss", "https":
+            components.scheme = "wss"
+            if components.port == 443 {
+                components.port = nil
+            }
+        case "ws", "http":
+            components.scheme = "ws"
+            if components.port == 80 {
+                components.port = nil
+            }
+        default:
+            return nil
+        }
+
+        components.host = rawHost
+        if components.path == "/" {
+            components.path = ""
+        }
+        components.fragment = nil
+
+        return components.string
+    }
+
+    static func directoryAddress(_ rawValue: String) -> String? {
+        guard var normalized = normalized(rawValue, defaultScheme: "wss") else { return nil }
+        for prefix in ["wss://", "ws://"] where normalized.hasPrefix(prefix) {
+            normalized.removeFirst(prefix.count)
+            break
+        }
+        return normalized
+    }
+}

bitchat/Nostr/XChaCha20Poly1305Compat.swift

@@ -0,0 +1,134 @@
+import Foundation
+import CryptoKit
+
+/// Minimal XChaCha20-Poly1305 compatibility wrapper using CryptoKit's ChaChaPoly.
+/// Implements HChaCha20 to derive a subkey and reduces the 24-byte nonce to a 12-byte nonce
+/// as per XChaCha20 construction.
+enum XChaCha20Poly1305Compat {
+
+    /// Errors that can occur during XChaCha20-Poly1305 operations
+    enum Error: Swift.Error {
+        case invalidKeyLength(expected: Int, got: Int)
+        case invalidNonceLength(expected: Int, got: Int)
+    }
+
+    struct SealBox {
+        let ciphertext: Data
+        let tag: Data
+    }
+
+    static func seal(plaintext: Data, key: Data, nonce24: Data, aad: Data? = nil) throws -> SealBox {
+        guard key.count == 32 else {
+            throw Error.invalidKeyLength(expected: 32, got: key.count)
+        }
+        guard nonce24.count == 24 else {
+            throw Error.invalidNonceLength(expected: 24, got: nonce24.count)
+        }
+
+        let subkey = try hchacha20(key: key, nonce16: Data(nonce24.prefix(16)))
+        let nonce12 = derive12ByteNonce(from24: nonce24)
+        let chachaKey = SymmetricKey(data: subkey)
+        let nonce = try ChaChaPoly.Nonce(data: nonce12)
+        let sealed = try ChaChaPoly.seal(plaintext, using: chachaKey, nonce: nonce, authenticating: aad ?? Data())
+        return SealBox(ciphertext: sealed.ciphertext, tag: sealed.tag)
+    }
+
+    static func open(ciphertext: Data, tag: Data, key: Data, nonce24: Data, aad: Data? = nil) throws -> Data {
+        guard key.count == 32 else {
+            throw Error.invalidKeyLength(expected: 32, got: key.count)
+        }
+        guard nonce24.count == 24 else {
+            throw Error.invalidNonceLength(expected: 24, got: nonce24.count)
+        }
+
+        let subkey = try hchacha20(key: key, nonce16: Data(nonce24.prefix(16)))
+        let nonce12 = derive12ByteNonce(from24: nonce24)
+        let chachaKey = SymmetricKey(data: subkey)
+        let box = try ChaChaPoly.SealedBox(nonce: ChaChaPoly.Nonce(data: nonce12), ciphertext: ciphertext, tag: tag)
+        return try ChaChaPoly.open(box, using: chachaKey, authenticating: aad ?? Data())
+    }
+
+    // MARK: - Internals
+
+    private static func derive12ByteNonce(from24 nonce24: Data) -> Data {
+        // XChaCha20-Poly1305: 12-byte nonce = 4 zero bytes || last 8 bytes of the 24-byte nonce
+        var out = Data(count: 12)
+        out.replaceSubrange(0..<4, with: [0, 0, 0, 0])
+        out.replaceSubrange(4..<12, with: nonce24.suffix(8))
+        return out
+    }
+
+    private static func hchacha20(key: Data, nonce16: Data) throws -> Data {
+        // HChaCha20 based on the original ChaCha20 core with a 16-byte nonce.
+        guard key.count == 32 else {
+            throw Error.invalidKeyLength(expected: 32, got: key.count)
+        }
+        guard nonce16.count == 16 else {
+            throw Error.invalidNonceLength(expected: 16, got: nonce16.count)
+        }
+
+        // Constants "expand 32-byte k"
+        var state: [UInt32] = [
+            0x61707865, 0x3320646e, 0x79622d32, 0x6b206574,
+            // key (8 words)
+            key.loadLEWord(0), key.loadLEWord(4), key.loadLEWord(8), key.loadLEWord(12),
+            key.loadLEWord(16), key.loadLEWord(20), key.loadLEWord(24), key.loadLEWord(28),
+            // nonce (4 words)
+            nonce16.loadLEWord(0), nonce16.loadLEWord(4), nonce16.loadLEWord(8), nonce16.loadLEWord(12)
+        ]
+
+        // 20 rounds (10 double rounds)
+        for _ in 0..<10 {
+            // Column rounds
+            quarterRound(&state, 0, 4, 8, 12)
+            quarterRound(&state, 1, 5, 9, 13)
+            quarterRound(&state, 2, 6, 10, 14)
+            quarterRound(&state, 3, 7, 11, 15)
+            // Diagonal rounds
+            quarterRound(&state, 0, 5, 10, 15)
+            quarterRound(&state, 1, 6, 11, 12)
+            quarterRound(&state, 2, 7, 8, 13)
+            quarterRound(&state, 3, 4, 9, 14)
+        }
+
+        // Output subkey: state[0..3] and state[12..15]
+        var out = Data(count: 32)
+        out.storeLEWord(state[0], at: 0)
+        out.storeLEWord(state[1], at: 4)
+        out.storeLEWord(state[2], at: 8)
+        out.storeLEWord(state[3], at: 12)
+        out.storeLEWord(state[12], at: 16)
+        out.storeLEWord(state[13], at: 20)
+        out.storeLEWord(state[14], at: 24)
+        out.storeLEWord(state[15], at: 28)
+        return out
+    }
+
+    private static func quarterRound(_ s: inout [UInt32], _ a: Int, _ b: Int, _ c: Int, _ d: Int) {
+        s[a] = s[a] &+ s[b]; s[d] ^= s[a]; s[d] = (s[d] << 16) | (s[d] >> 16)
+        s[c] = s[c] &+ s[d]; s[b] ^= s[c]; s[b] = (s[b] << 12) | (s[b] >> 20)
+        s[a] = s[a] &+ s[b]; s[d] ^= s[a]; s[d] = (s[d] << 8)  | (s[d] >> 24)
+        s[c] = s[c] &+ s[d]; s[b] ^= s[c]; s[b] = (s[b] << 7)  | (s[b] >> 25)
+    }
+}
+
+private extension Data {
+    func loadLEWord(_ offset: Int) -> UInt32 {
+        let range = offset..<(offset+4)
+        let bytes = self[range]
+        return bytes.withUnsafeBytes { ptr -> UInt32 in
+            let b = ptr.bindMemory(to: UInt8.self)
+            return UInt32(b[0]) | (UInt32(b[1]) << 8) | (UInt32(b[2]) << 16) | (UInt32(b[3]) << 24)
+        }
+    }
+
+    mutating func storeLEWord(_ value: UInt32, at offset: Int) {
+        let bytes: [UInt8] = [
+            UInt8(value & 0xff),
+            UInt8((value >> 8) & 0xff),
+            UInt8((value >> 16) & 0xff),
+            UInt8((value >> 24) & 0xff)
+        ]
+        replaceSubrange(offset..<(offset+4), with: bytes)
+    }
+}

bitchat/Protocols/BinaryProtocol.swift

@@ -1,550 +0,0 @@
-//
-// BinaryProtocol.swift
-// bitchat
-//
-// This is free and unencumbered software released into the public domain.
-// For more information, see <https://unlicense.org>
-//
-
-///
-/// # BinaryProtocol
-///
-/// Low-level binary encoding and decoding for BitChat protocol messages.
-/// Optimized for Bluetooth LE's limited bandwidth and MTU constraints.
-///
-/// ## Overview
-/// BinaryProtocol implements an efficient binary wire format that minimizes
-/// overhead while maintaining extensibility. It handles:
-/// - Compact binary encoding with fixed headers
-/// - Optional field support via flags
-/// - Automatic compression for large payloads
-/// - Endianness handling for cross-platform compatibility
-///
-/// ## Wire Format
-/// ```
-/// Header (Fixed 13 bytes):
-/// +--------+------+-----+-----------+-------+----------------+
-/// |Version | Type | TTL | Timestamp | Flags | PayloadLength  |
-/// |1 byte  |1 byte|1byte| 8 bytes   | 1 byte| 2 bytes        |
-/// +--------+------+-----+-----------+-------+----------------+
-///
-/// Variable sections:
-/// +----------+-------------+---------+------------+
-/// | SenderID | RecipientID | Payload | Signature  |
-/// | 8 bytes  | 8 bytes*    | Variable| 64 bytes*  |
-/// +----------+-------------+---------+------------+
-/// * Optional fields based on flags
-/// ```
-///
-/// ## Design Rationale
-/// The protocol is designed for:
-/// - **Efficiency**: Minimal overhead for small messages
-/// - **Flexibility**: Optional fields via flag bits
-/// - **Compatibility**: Network byte order (big-endian)
-/// - **Performance**: Zero-copy where possible
-///
-/// ## Compression Strategy
-/// - Automatic compression for payloads > 256 bytes
-/// - LZ4 algorithm for speed over ratio
-/// - Original size stored for decompression
-/// - Flag bit indicates compressed payload
-///
-/// ## Flag Bits
-/// - Bit 0: Has recipient ID (directed message)
-/// - Bit 1: Has signature (authenticated message)
-/// - Bit 2: Is compressed (LZ4 compression applied)
-/// - Bits 3-7: Reserved for future use
-///
-/// ## Size Constraints
-/// - Maximum packet size: 65,535 bytes (16-bit length field)
-/// - Typical packet size: < 512 bytes (BLE MTU)
-/// - Minimum packet size: 21 bytes (header + sender ID)
-///
-/// ## Encoding Process
-/// 1. Construct header with fixed fields
-/// 2. Set appropriate flags
-/// 3. Compress payload if beneficial
-/// 4. Append variable-length fields
-/// 5. Calculate and append signature if needed
-///
-/// ## Decoding Process
-/// 1. Validate minimum packet size
-/// 2. Parse fixed header
-/// 3. Extract flags and determine field presence
-/// 4. Parse variable fields based on flags
-/// 5. Decompress payload if compressed
-/// 6. Verify signature if present
-///
-/// ## Error Handling
-/// - Graceful handling of malformed packets
-/// - Clear error messages for debugging
-/// - No crashes on invalid input
-/// - Logging of protocol violations
-///
-/// ## Performance Notes
-/// - Allocation-free for small messages
-/// - Streaming support for large payloads
-/// - Efficient bit manipulation
-/// - Platform-optimized byte swapping
-///
-
-import Foundation
-
-extension Data {
-    func trimmingNullBytes() -> Data {
-        // Find the first null byte
-        if let nullIndex = self.firstIndex(of: 0) {
-            return self.prefix(nullIndex)
-        }
-        return self
-    }
-}
-
-/// Implements binary encoding and decoding for BitChat protocol messages.
-/// Provides static methods for converting between BitchatPacket objects and
-/// their binary wire format representation.
-/// - Note: All multi-byte values use network byte order (big-endian)
-struct BinaryProtocol {
-    static let headerSize = 13
-    static let senderIDSize = 8
-    static let recipientIDSize = 8
-    static let signatureSize = 64
-    
-    struct Flags {
-        static let hasRecipient: UInt8 = 0x01
-        static let hasSignature: UInt8 = 0x02
-        static let isCompressed: UInt8 = 0x04
-    }
-    
-    // Encode BitchatPacket to binary format
-    static func encode(_ packet: BitchatPacket) -> Data? {
-        var data = Data()
-        
-        
-        // Try to compress payload if beneficial
-        var payload = packet.payload
-        var originalPayloadSize: UInt16? = nil
-        var isCompressed = false
-        
-        if CompressionUtil.shouldCompress(payload) {
-            if let compressedPayload = CompressionUtil.compress(payload) {
-                // Store original size for decompression (2 bytes after payload)
-                originalPayloadSize = UInt16(payload.count)
-                payload = compressedPayload
-                isCompressed = true
-                
-            } else {
-            }
-        } else {
-        }
-        
-        // Header
-        data.append(packet.version)
-        data.append(packet.type)
-        data.append(packet.ttl)
-        
-        // Timestamp (8 bytes, big-endian)
-        for i in (0..<8).reversed() {
-            data.append(UInt8((packet.timestamp >> (i * 8)) & 0xFF))
-        }
-        
-        // Flags
-        var flags: UInt8 = 0
-        if packet.recipientID != nil {
-            flags |= Flags.hasRecipient
-        }
-        if packet.signature != nil {
-            flags |= Flags.hasSignature
-        }
-        if isCompressed {
-            flags |= Flags.isCompressed
-        }
-        data.append(flags)
-        
-        // Payload length (2 bytes, big-endian) - includes original size if compressed
-        let payloadDataSize = payload.count + (isCompressed ? 2 : 0)
-        let payloadLength = UInt16(payloadDataSize)
-        
-        
-        data.append(UInt8((payloadLength >> 8) & 0xFF))
-        data.append(UInt8(payloadLength & 0xFF))
-        
-        // SenderID (exactly 8 bytes)
-        let senderBytes = packet.senderID.prefix(senderIDSize)
-        data.append(senderBytes)
-        if senderBytes.count < senderIDSize {
-            data.append(Data(repeating: 0, count: senderIDSize - senderBytes.count))
-        }
-        
-        // RecipientID (if present)
-        if let recipientID = packet.recipientID {
-            let recipientBytes = recipientID.prefix(recipientIDSize)
-            data.append(recipientBytes)
-            if recipientBytes.count < recipientIDSize {
-                data.append(Data(repeating: 0, count: recipientIDSize - recipientBytes.count))
-            }
-        }
-        
-        // Payload (with original size prepended if compressed)
-        if isCompressed, let originalSize = originalPayloadSize {
-            // Prepend original size (2 bytes, big-endian)
-            data.append(UInt8((originalSize >> 8) & 0xFF))
-            data.append(UInt8(originalSize & 0xFF))
-        }
-        data.append(payload)
-        
-        // Signature (if present)
-        if let signature = packet.signature {
-            data.append(signature.prefix(signatureSize))
-        }
-        
-        
-        // Apply padding to standard block sizes for traffic analysis resistance
-        let optimalSize = MessagePadding.optimalBlockSize(for: data.count)
-        let paddedData = MessagePadding.pad(data, toSize: optimalSize)
-        
-        
-        return paddedData
-    }
-    
-    // Decode binary data to BitchatPacket
-    static func decode(_ data: Data) -> BitchatPacket? {
-        // Remove padding first
-        let unpaddedData = MessagePadding.unpad(data)
-        
-        
-        guard unpaddedData.count >= headerSize + senderIDSize else { 
-            return nil 
-        }
-        
-        var offset = 0
-        
-        // Header
-        let version = unpaddedData[offset]; offset += 1
-        // Check if version is supported
-        guard ProtocolVersion.isSupported(version) else { 
-            // Log unsupported version for debugging
-            return nil 
-        }
-        let type = unpaddedData[offset]; offset += 1
-        let ttl = unpaddedData[offset]; offset += 1
-        
-        // Timestamp
-        let timestampData = unpaddedData[offset..<offset+8]
-        let timestamp = timestampData.reduce(0) { result, byte in
-            (result << 8) | UInt64(byte)
-        }
-        offset += 8
-        
-        // Flags
-        let flags = unpaddedData[offset]; offset += 1
-        let hasRecipient = (flags & Flags.hasRecipient) != 0
-        let hasSignature = (flags & Flags.hasSignature) != 0
-        let isCompressed = (flags & Flags.isCompressed) != 0
-        
-        // Payload length
-        let payloadLengthData = unpaddedData[offset..<offset+2]
-        let payloadLength = payloadLengthData.reduce(0) { result, byte in
-            (result << 8) | UInt16(byte)
-        }
-        offset += 2
-        
-        // Calculate expected total size
-        var expectedSize = headerSize + senderIDSize + Int(payloadLength)
-        if hasRecipient {
-            expectedSize += recipientIDSize
-        }
-        if hasSignature {
-            expectedSize += signatureSize
-        }
-        
-        guard unpaddedData.count >= expectedSize else { 
-            return nil 
-        }
-        
-        // SenderID
-        let senderID = unpaddedData[offset..<offset+senderIDSize]
-        offset += senderIDSize
-        
-        // RecipientID
-        var recipientID: Data?
-        if hasRecipient {
-            recipientID = unpaddedData[offset..<offset+recipientIDSize]
-            offset += recipientIDSize
-        }
-        
-        // Payload
-        let payload: Data
-        if isCompressed {
-            // First 2 bytes are original size
-            guard Int(payloadLength) >= 2 else { return nil }
-            let originalSizeData = unpaddedData[offset..<offset+2]
-            let originalSize = Int(originalSizeData.reduce(0) { result, byte in
-                (result << 8) | UInt16(byte)
-            })
-            offset += 2
-            
-            // Compressed payload
-            let compressedPayload = unpaddedData[offset..<offset+Int(payloadLength)-2]
-            offset += Int(payloadLength) - 2
-            
-            // Decompress
-            guard let decompressedPayload = CompressionUtil.decompress(compressedPayload, originalSize: originalSize) else {
-                return nil
-            }
-            payload = decompressedPayload
-        } else {
-            payload = unpaddedData[offset..<offset+Int(payloadLength)]
-            offset += Int(payloadLength)
-        }
-        
-        // Signature
-        var signature: Data?
-        if hasSignature {
-            signature = unpaddedData[offset..<offset+signatureSize]
-        }
-        
-        return BitchatPacket(
-            type: type,
-            senderID: senderID,
-            recipientID: recipientID,
-            timestamp: timestamp,
-            payload: payload,
-            signature: signature,
-            ttl: ttl
-        )
-    }
-}
-
-// Binary encoding for BitchatMessage
-extension BitchatMessage {
-    func toBinaryPayload() -> Data? {
-        var data = Data()
-        
-        // Message format:
-        // - Flags: 1 byte (bit 0: isRelay, bit 1: isPrivate, bit 2: hasOriginalSender, bit 3: hasRecipientNickname, bit 4: hasSenderPeerID, bit 5: hasMentions)
-        // - Timestamp: 8 bytes (seconds since epoch)
-        // - ID length: 1 byte
-        // - ID: variable
-        // - Sender length: 1 byte
-        // - Sender: variable
-        // - Content length: 2 bytes
-        // - Content: variable
-        // Optional fields based on flags:
-        // - Original sender length + data
-        // - Recipient nickname length + data
-        // - Sender peer ID length + data
-        // - Mentions array
-        
-        var flags: UInt8 = 0
-        if isRelay { flags |= 0x01 }
-        if isPrivate { flags |= 0x02 }
-        if originalSender != nil { flags |= 0x04 }
-        if recipientNickname != nil { flags |= 0x08 }
-        if senderPeerID != nil { flags |= 0x10 }
-        if mentions != nil && !mentions!.isEmpty { flags |= 0x20 }
-        
-        data.append(flags)
-        
-        // Timestamp (in milliseconds)
-        let timestampMillis = UInt64(timestamp.timeIntervalSince1970 * 1000)
-        // Encode as 8 bytes, big-endian
-        for i in (0..<8).reversed() {
-            data.append(UInt8((timestampMillis >> (i * 8)) & 0xFF))
-        }
-        
-        // ID
-        if let idData = id.data(using: .utf8) {
-            data.append(UInt8(min(idData.count, 255)))
-            data.append(idData.prefix(255))
-        } else {
-            data.append(0)
-        }
-        
-        // Sender
-        if let senderData = sender.data(using: .utf8) {
-            data.append(UInt8(min(senderData.count, 255)))
-            data.append(senderData.prefix(255))
-        } else {
-            data.append(0)
-        }
-        
-        // Content
-        if let contentData = content.data(using: .utf8) {
-            let length = UInt16(min(contentData.count, 65535))
-            // Encode length as 2 bytes, big-endian
-            data.append(UInt8((length >> 8) & 0xFF))
-            data.append(UInt8(length & 0xFF))
-            data.append(contentData.prefix(Int(length)))
-        } else {
-            data.append(contentsOf: [0, 0])
-        }
-        
-        // Optional fields
-        if let originalSender = originalSender, let origData = originalSender.data(using: .utf8) {
-            data.append(UInt8(min(origData.count, 255)))
-            data.append(origData.prefix(255))
-        }
-        
-        if let recipientNickname = recipientNickname, let recipData = recipientNickname.data(using: .utf8) {
-            data.append(UInt8(min(recipData.count, 255)))
-            data.append(recipData.prefix(255))
-        }
-        
-        if let senderPeerID = senderPeerID, let peerData = senderPeerID.data(using: .utf8) {
-            data.append(UInt8(min(peerData.count, 255)))
-            data.append(peerData.prefix(255))
-        }
-        
-        // Mentions array
-        if let mentions = mentions {
-            data.append(UInt8(min(mentions.count, 255))) // Number of mentions
-            for mention in mentions.prefix(255) {
-                if let mentionData = mention.data(using: .utf8) {
-                    data.append(UInt8(min(mentionData.count, 255)))
-                    data.append(mentionData.prefix(255))
-                } else {
-                    data.append(0)
-                }
-            }
-        }
-        
-        
-        return data
-    }
-    
-    static func fromBinaryPayload(_ data: Data) -> BitchatMessage? {
-        // Create an immutable copy to prevent threading issues
-        let dataCopy = Data(data)
-        
-        
-        guard dataCopy.count >= 13 else { 
-            return nil 
-        }
-        
-        var offset = 0
-        
-        // Flags
-        guard offset < dataCopy.count else { 
-            return nil 
-        }
-        let flags = dataCopy[offset]; offset += 1
-        let isRelay = (flags & 0x01) != 0
-        let isPrivate = (flags & 0x02) != 0
-        let hasOriginalSender = (flags & 0x04) != 0
-        let hasRecipientNickname = (flags & 0x08) != 0
-        let hasSenderPeerID = (flags & 0x10) != 0
-        let hasMentions = (flags & 0x20) != 0
-        
-        // Timestamp
-        guard offset + 8 <= dataCopy.count else { 
-            return nil 
-        }
-        let timestampData = dataCopy[offset..<offset+8]
-        let timestampMillis = timestampData.reduce(0) { result, byte in
-            (result << 8) | UInt64(byte)
-        }
-        offset += 8
-        let timestamp = Date(timeIntervalSince1970: TimeInterval(timestampMillis) / 1000.0)
-        
-        // ID
-        guard offset < dataCopy.count else { 
-            return nil 
-        }
-        let idLength = Int(dataCopy[offset]); offset += 1
-        guard offset + idLength <= dataCopy.count else { 
-            return nil 
-        }
-        let id = String(data: dataCopy[offset..<offset+idLength], encoding: .utf8) ?? UUID().uuidString
-        offset += idLength
-        
-        // Sender
-        guard offset < dataCopy.count else { 
-            return nil 
-        }
-        let senderLength = Int(dataCopy[offset]); offset += 1
-        guard offset + senderLength <= dataCopy.count else { 
-            return nil 
-        }
-        let sender = String(data: dataCopy[offset..<offset+senderLength], encoding: .utf8) ?? "unknown"
-        offset += senderLength
-        
-        // Content
-        guard offset + 2 <= dataCopy.count else { 
-            return nil 
-        }
-        let contentLengthData = dataCopy[offset..<offset+2]
-        let contentLength = Int(contentLengthData.reduce(0) { result, byte in
-            (result << 8) | UInt16(byte)
-        })
-        offset += 2
-        guard offset + contentLength <= dataCopy.count else { 
-            return nil 
-        }
-        
-        let content = String(data: dataCopy[offset..<offset+contentLength], encoding: .utf8) ?? ""
-        offset += contentLength
-        
-        // Optional fields
-        var originalSender: String?
-        if hasOriginalSender && offset < dataCopy.count {
-            let length = Int(dataCopy[offset]); offset += 1
-            if offset + length <= dataCopy.count {
-                originalSender = String(data: dataCopy[offset..<offset+length], encoding: .utf8)
-                offset += length
-            }
-        }
-        
-        var recipientNickname: String?
-        if hasRecipientNickname && offset < dataCopy.count {
-            let length = Int(dataCopy[offset]); offset += 1
-            if offset + length <= dataCopy.count {
-                recipientNickname = String(data: dataCopy[offset..<offset+length], encoding: .utf8)
-                offset += length
-            }
-        }
-        
-        var senderPeerID: String?
-        if hasSenderPeerID && offset < dataCopy.count {
-            let length = Int(dataCopy[offset]); offset += 1
-            if offset + length <= dataCopy.count {
-                senderPeerID = String(data: dataCopy[offset..<offset+length], encoding: .utf8)
-                offset += length
-            }
-        }
-        
-        // Mentions array
-        var mentions: [String]?
-        if hasMentions && offset < dataCopy.count {
-            let mentionCount = Int(dataCopy[offset]); offset += 1
-            if mentionCount > 0 {
-                mentions = []
-                for _ in 0..<mentionCount {
-                    if offset < dataCopy.count {
-                        let length = Int(dataCopy[offset]); offset += 1
-                        if offset + length <= dataCopy.count {
-                            if let mention = String(data: dataCopy[offset..<offset+length], encoding: .utf8) {
-                                mentions?.append(mention)
-                            }
-                            offset += length
-                        }
-                    }
-                }
-            }
-        }
-        
-        let message = BitchatMessage(
-            id: id,
-            sender: sender,
-            content: content,
-            timestamp: timestamp,
-            isRelay: isRelay,
-            originalSender: originalSender,
-            isPrivate: isPrivate,
-            recipientNickname: recipientNickname,
-            senderPeerID: senderPeerID,
-            mentions: mentions
-        )
-        return message
-    }
-}

bitchat/Protocols/BitchatFilePacket.swift

@@ -0,0 +1,160 @@
+//
+// BitchatFilePacket.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import Foundation
+import BitFoundation
+import BitLogger
+
+/// TLV payload for Bluetooth mesh file transfers (voice notes, images, generic files).
+/// Mirrors the Android client specification to ensure cross-platform interoperability.
+struct BitchatFilePacket {
+    var fileName: String?
+    var fileSize: UInt64?
+    var mimeType: String?
+    var content: Data
+
+    /// Canonical TLV tags defined by the Android implementation.
+    private enum TLVType: UInt8 {
+        case fileName = 0x01
+        case fileSize = 0x02
+        case mimeType = 0x03
+        case content = 0x04
+    }
+
+    /// Encodes the packet using v2 canonical TLVs (4-byte FILE_SIZE, 4-byte CONTENT length).
+    /// Returns `nil` when fields exceed protocol limits (e.g., content > UInt32.max).
+    /// `limit` defaults to the Bluetooth payload cap; Wi-Fi bulk transfers pass
+    /// `FileTransferLimits.maxWifiBulkPayloadBytes`.
+    func encode(limit: Int = FileTransferLimits.maxPayloadBytes) -> Data? {
+        let resolvedSize = fileSize ?? UInt64(content.count)
+        guard resolvedSize <= UInt64(UInt32.max) else { return nil }
+        guard resolvedSize <= UInt64(limit) else { return nil }
+        guard content.count <= Int(UInt32.max) else { return nil }
+        guard FileTransferLimits.isValidPayload(content.count, limit: limit) else { return nil }
+
+        func appendBE<T: FixedWidthInteger>(_ value: T, into data: inout Data) {
+            var big = value.bigEndian
+            withUnsafeBytes(of: &big) { data.append(contentsOf: $0) }
+        }
+
+        var encoded = Data()
+
+        if let name = fileName, let nameData = name.data(using: .utf8), nameData.count <= Int(UInt16.max) {
+            encoded.append(TLVType.fileName.rawValue)
+            appendBE(UInt16(nameData.count), into: &encoded)
+            encoded.append(nameData)
+        }
+
+        encoded.append(TLVType.fileSize.rawValue)
+        appendBE(UInt16(4), into: &encoded)
+        appendBE(UInt32(resolvedSize), into: &encoded)
+
+        if let mime = mimeType, let mimeData = mime.data(using: .utf8), mimeData.count <= Int(UInt16.max) {
+            encoded.append(TLVType.mimeType.rawValue)
+            appendBE(UInt16(mimeData.count), into: &encoded)
+            encoded.append(mimeData)
+        }
+
+        encoded.append(TLVType.content.rawValue)
+        appendBE(UInt32(content.count), into: &encoded)
+        encoded.append(content)
+
+        return encoded
+    }
+
+    /// Decodes TLV payloads, tolerating legacy encodings (FILE_SIZE len=8, CONTENT len=2) when possible.
+    /// `limit` defaults to the Bluetooth payload cap; Wi-Fi bulk transfers pass
+    /// the (smaller of the) accepted-offer size and the Wi-Fi bulk ceiling.
+    static func decode(_ data: Data, limit: Int = FileTransferLimits.maxPayloadBytes) -> BitchatFilePacket? {
+        var cursor = data.startIndex
+        let end = data.endIndex
+
+        var fileName: String?
+        var fileSize: UInt64?
+        var mimeType: String?
+        var content = Data()
+
+        while cursor < end {
+            let typeRaw = data[cursor]
+            cursor = data.index(after: cursor)
+
+            guard cursor <= end else { return nil }
+            let tlvType = TLVType(rawValue: typeRaw)
+
+            func readBigEndianLength(bytes: Int) -> Int? {
+                guard data.distance(from: cursor, to: end) >= bytes else { return nil }
+                // Use UInt64 to prevent integer overflow during shift operations
+                var result: UInt64 = 0
+                for _ in 0..<bytes {
+                    result = (result << 8) | UInt64(data[cursor])
+                    cursor = data.index(after: cursor)
+                }
+                // Safely convert to Int with overflow check
+                guard result <= Int.max else { return nil }
+                return Int(result)
+            }
+
+            let length: Int?
+            if tlvType == .content {
+                let snapshot = cursor
+                let canonical = readBigEndianLength(bytes: 4)
+                if let canonical = canonical,
+                   canonical <= data.distance(from: cursor, to: end) {
+                    length = canonical
+                } else {
+                    cursor = snapshot
+                    length = readBigEndianLength(bytes: 2)
+                }
+            } else {
+                length = readBigEndianLength(bytes: 2)
+            }
+
+            guard let tlvLength = length, tlvLength >= 0 else { return nil }
+            guard data.distance(from: cursor, to: end) >= tlvLength else { return nil }
+
+            let valueStart = cursor
+            cursor = data.index(cursor, offsetBy: tlvLength)
+            let value = data[valueStart..<cursor]
+
+            switch tlvType {
+            case .fileName:
+                fileName = String(data: Data(value), encoding: .utf8)
+            case .fileSize:
+                if tlvLength == 4 || tlvLength == 8 {
+                    var size: UInt64 = 0
+                    for byte in value {
+                        size = (size << 8) | UInt64(byte)
+                    }
+                    if size > UInt64(limit) {
+                        return nil
+                    }
+                    fileSize = size
+                }
+            case .mimeType:
+                mimeType = String(data: Data(value), encoding: .utf8)
+            case .content:
+                let proposedSize = content.count + value.count
+                if proposedSize > limit {
+                    return nil
+                }
+                content.append(contentsOf: value)
+            case nil:
+                continue
+            }
+        }
+
+        guard !content.isEmpty else { return nil }
+        guard FileTransferLimits.isValidPayload(content.count, limit: limit) else { return nil }
+        return BitchatFilePacket(
+            fileName: fileName,
+            fileSize: fileSize ?? UInt64(content.count),
+            mimeType: mimeType,
+            content: content
+        )
+    }
+}

bitchat/Protocols/BoardPackets.swift

@@ -0,0 +1,348 @@
+//
+// BoardPackets.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import CryptoKit
+import Foundation
+
+// MARK: - Board wire format (MessageType.boardPost payloads)
+//
+// TLV layout (type u8, length u16 big-endian, value), matching REQUEST_SYNC:
+//  - 0x01: kind (u8) — 0x01 post, 0x02 tombstone
+//  - 0x02: postID (16B random)
+//  - 0x03: geohash (UTF-8, empty = mesh-local board, max 12 chars)
+//  - 0x04: content (UTF-8, 1...512 bytes) [post]
+//  - 0x05: authorSigningKey (32B Ed25519 public key)
+//  - 0x06: authorNickname (UTF-8, max 64 bytes)
+//  - 0x07: createdAt (u64 big-endian, ms) [post]
+//  - 0x08: expiresAt (u64 big-endian, ms, max 7 days after createdAt) [post]
+//  - 0x09: flags (u8, bit0 = urgent) [post]
+//  - 0x0A: signature (64B Ed25519)
+//  - 0x0B: deletedAt (u64 big-endian, ms) [tombstone]
+// Unknown TLVs are skipped for forward compatibility.
+
+enum BoardWireConstants {
+    static let postIDLength = 16
+    static let signingKeyLength = 32
+    static let signatureLength = 64
+    static let contentMaxBytes = 512
+    static let nicknameMaxBytes = 64
+    static let geohashMaxLength = 12
+    /// Posts may live at most 7 days past their creation timestamp.
+    static let maxLifetimeMs: UInt64 = 7 * 24 * 60 * 60 * 1000
+    static let postSigningContext = "bitchat-board-v1"
+    static let tombstoneSigningContext = "bitchat-board-del-v1"
+    static let geohashAlphabet = Set("0123456789bcdefghjkmnpqrstuvwxyz")
+}
+
+private enum BoardTLVType: UInt8 {
+    case kind = 0x01
+    case postID = 0x02
+    case geohash = 0x03
+    case content = 0x04
+    case authorSigningKey = 0x05
+    case authorNickname = 0x06
+    case createdAt = 0x07
+    case expiresAt = 0x08
+    case flags = 0x09
+    case signature = 0x0A
+    case deletedAt = 0x0B
+}
+
+private enum BoardWireKind: UInt8 {
+    case post = 0x01
+    case tombstone = 0x02
+}
+
+/// A signed, persistent bulletin-board notice.
+struct BoardPostPacket: Equatable {
+    let postID: Data
+    /// Empty string scopes the post to the mesh-local board.
+    let geohash: String
+    let content: String
+    let authorSigningKey: Data
+    let authorNickname: String
+    let createdAt: UInt64
+    let expiresAt: UInt64
+    let flags: UInt8
+    let signature: Data
+
+    static let urgentFlag: UInt8 = 0x01
+
+    var isUrgent: Bool { flags & Self.urgentFlag != 0 }
+
+    /// Canonical bytes covered by the Ed25519 signature. Variable-length
+    /// fields are length-prefixed so no two field combinations can collide.
+    static func signingBytes(
+        postID: Data,
+        geohash: String,
+        content: String,
+        authorSigningKey: Data,
+        authorNickname: String,
+        createdAt: UInt64,
+        expiresAt: UInt64,
+        flags: UInt8
+    ) -> Data {
+        var out = Data()
+        BoardWireEncoding.appendContext(BoardWireConstants.postSigningContext, to: &out)
+        out.append(postID)
+        BoardWireEncoding.appendLengthPrefixed(Data(geohash.utf8), to: &out)
+        BoardWireEncoding.appendLengthPrefixed(Data(content.utf8), to: &out)
+        out.append(authorSigningKey)
+        BoardWireEncoding.appendLengthPrefixed(Data(authorNickname.utf8), to: &out)
+        BoardWireEncoding.appendUInt64(createdAt, to: &out)
+        BoardWireEncoding.appendUInt64(expiresAt, to: &out)
+        out.append(flags)
+        return out
+    }
+
+    var signingBytes: Data {
+        Self.signingBytes(
+            postID: postID,
+            geohash: geohash,
+            content: content,
+            authorSigningKey: authorSigningKey,
+            authorNickname: authorNickname,
+            createdAt: createdAt,
+            expiresAt: expiresAt,
+            flags: flags
+        )
+    }
+
+    func verifySignature() -> Bool {
+        BoardWireEncoding.verify(signature: signature, over: signingBytes, publicKey: authorSigningKey)
+    }
+}
+
+/// A signed deletion marker. Only the author's key can produce one; receivers
+/// keep it until the post's original expiry so the delete outruns the post.
+struct BoardTombstonePacket: Equatable {
+    let postID: Data
+    let authorSigningKey: Data
+    let deletedAt: UInt64
+    let signature: Data
+
+    static func signingBytes(postID: Data, deletedAt: UInt64) -> Data {
+        var out = Data()
+        BoardWireEncoding.appendContext(BoardWireConstants.tombstoneSigningContext, to: &out)
+        out.append(postID)
+        BoardWireEncoding.appendUInt64(deletedAt, to: &out)
+        return out
+    }
+
+    var signingBytes: Data {
+        Self.signingBytes(postID: postID, deletedAt: deletedAt)
+    }
+
+    func verifySignature() -> Bool {
+        BoardWireEncoding.verify(signature: signature, over: signingBytes, publicKey: authorSigningKey)
+    }
+}
+
+/// Decoded board payload: either a live post or a tombstone.
+enum BoardWire: Equatable {
+    case post(BoardPostPacket)
+    case tombstone(BoardTombstonePacket)
+
+    func encode() -> Data {
+        var out = Data()
+        func putTLV(_ t: BoardTLVType, _ v: Data) {
+            out.append(t.rawValue)
+            let len = UInt16(v.count)
+            out.append(UInt8((len >> 8) & 0xFF))
+            out.append(UInt8(len & 0xFF))
+            out.append(v)
+        }
+        switch self {
+        case .post(let post):
+            putTLV(.kind, Data([BoardWireKind.post.rawValue]))
+            putTLV(.postID, post.postID)
+            putTLV(.geohash, Data(post.geohash.utf8))
+            putTLV(.content, Data(post.content.utf8))
+            putTLV(.authorSigningKey, post.authorSigningKey)
+            putTLV(.authorNickname, Data(post.authorNickname.utf8))
+            putTLV(.createdAt, BoardWireEncoding.uint64Data(post.createdAt))
+            putTLV(.expiresAt, BoardWireEncoding.uint64Data(post.expiresAt))
+            putTLV(.flags, Data([post.flags]))
+            putTLV(.signature, post.signature)
+        case .tombstone(let tombstone):
+            putTLV(.kind, Data([BoardWireKind.tombstone.rawValue]))
+            putTLV(.postID, tombstone.postID)
+            putTLV(.authorSigningKey, tombstone.authorSigningKey)
+            putTLV(.deletedAt, BoardWireEncoding.uint64Data(tombstone.deletedAt))
+            putTLV(.signature, tombstone.signature)
+        }
+        return out
+    }
+
+    /// Structural decode; the caller must still verify the signature before
+    /// ingesting (`verifySignature()`).
+    static func decode(from data: Data) -> BoardWire? {
+        var off = data.startIndex
+        var kind: BoardWireKind?
+        var postID: Data?
+        var geohash: String?
+        var content: String?
+        var contentBytes = 0
+        var authorSigningKey: Data?
+        var authorNickname: String?
+        var nicknameBytes = 0
+        var createdAt: UInt64?
+        var expiresAt: UInt64?
+        var flags: UInt8?
+        var signature: Data?
+        var deletedAt: UInt64?
+
+        while off + 3 <= data.endIndex {
+            let t = data[off]; off += 1
+            let len = (Int(data[off]) << 8) | Int(data[off + 1]); off += 2
+            guard off + len <= data.endIndex else { return nil }
+            let v = data.subdata(in: off..<(off + len)); off += len
+            switch BoardTLVType(rawValue: t) {
+            case .kind:
+                guard v.count == 1 else { return nil }
+                kind = BoardWireKind(rawValue: v[v.startIndex])
+            case .postID:
+                guard v.count == BoardWireConstants.postIDLength else { return nil }
+                postID = v
+            case .geohash:
+                guard v.count <= BoardWireConstants.geohashMaxLength else { return nil }
+                geohash = String(data: v, encoding: .utf8)
+            case .content:
+                guard v.count <= BoardWireConstants.contentMaxBytes else { return nil }
+                contentBytes = v.count
+                content = String(data: v, encoding: .utf8)
+            case .authorSigningKey:
+                guard v.count == BoardWireConstants.signingKeyLength else { return nil }
+                authorSigningKey = v
+            case .authorNickname:
+                guard v.count <= BoardWireConstants.nicknameMaxBytes else { return nil }
+                nicknameBytes = v.count
+                authorNickname = String(data: v, encoding: .utf8)
+            case .createdAt:
+                createdAt = BoardWireEncoding.uint64(from: v)
+            case .expiresAt:
+                expiresAt = BoardWireEncoding.uint64(from: v)
+            case .flags:
+                guard v.count == 1 else { return nil }
+                flags = v[v.startIndex]
+            case .signature:
+                guard v.count == BoardWireConstants.signatureLength else { return nil }
+                signature = v
+            case .deletedAt:
+                deletedAt = BoardWireEncoding.uint64(from: v)
+            case nil:
+                continue // forward compatible; ignore unknown TLVs
+            }
+        }
+
+        guard let postID, let authorSigningKey, let signature else { return nil }
+
+        switch kind {
+        case .post:
+            guard let geohash, let content, let authorNickname,
+                  let createdAt, let expiresAt, let flags,
+                  contentBytes >= 1,
+                  nicknameBytes <= BoardWireConstants.nicknameMaxBytes,
+                  isValidGeohashField(geohash),
+                  expiresAt > createdAt,
+                  expiresAt - createdAt <= BoardWireConstants.maxLifetimeMs else {
+                return nil
+            }
+            return .post(BoardPostPacket(
+                postID: postID,
+                geohash: geohash,
+                content: content,
+                authorSigningKey: authorSigningKey,
+                authorNickname: authorNickname,
+                createdAt: createdAt,
+                expiresAt: expiresAt,
+                flags: flags,
+                signature: signature
+            ))
+        case .tombstone:
+            guard let deletedAt else { return nil }
+            return .tombstone(BoardTombstonePacket(
+                postID: postID,
+                authorSigningKey: authorSigningKey,
+                deletedAt: deletedAt,
+                signature: signature
+            ))
+        case nil:
+            return nil
+        }
+    }
+
+    func verifySignature() -> Bool {
+        switch self {
+        case .post(let post): return post.verifySignature()
+        case .tombstone(let tombstone): return tombstone.verifySignature()
+        }
+    }
+
+    /// Cheap TLV peek for relay policy: is this payload an urgent post?
+    /// Avoids a full decode on the hot relay path.
+    static func urgentFlag(in data: Data) -> Bool {
+        var off = data.startIndex
+        while off + 3 <= data.endIndex {
+            let t = data[off]; off += 1
+            let len = (Int(data[off]) << 8) | Int(data[off + 1]); off += 2
+            guard off + len <= data.endIndex else { return false }
+            if t == BoardTLVType.flags.rawValue, len == 1 {
+                return data[off] & BoardPostPacket.urgentFlag != 0
+            }
+            off += len
+        }
+        return false
+    }
+
+    /// Empty geohash = mesh-local board; otherwise 1-12 chars of the geohash
+    /// base32 alphabet.
+    private static func isValidGeohashField(_ geohash: String) -> Bool {
+        geohash.isEmpty || geohash.allSatisfy { BoardWireConstants.geohashAlphabet.contains($0) }
+    }
+}
+
+enum BoardWireEncoding {
+    static func appendContext(_ context: String, to out: inout Data) {
+        let bytes = Data(context.utf8)
+        out.append(UInt8(min(bytes.count, 255)))
+        out.append(bytes.prefix(255))
+    }
+
+    static func appendLengthPrefixed(_ value: Data, to out: inout Data) {
+        let len = UInt16(min(value.count, Int(UInt16.max)))
+        out.append(UInt8((len >> 8) & 0xFF))
+        out.append(UInt8(len & 0xFF))
+        out.append(value.prefix(Int(UInt16.max)))
+    }
+
+    static func appendUInt64(_ value: UInt64, to out: inout Data) {
+        var be = value.bigEndian
+        withUnsafeBytes(of: &be) { out.append(contentsOf: $0) }
+    }
+
+    static func uint64Data(_ value: UInt64) -> Data {
+        var out = Data()
+        appendUInt64(value, to: &out)
+        return out
+    }
+
+    static func uint64(from data: Data) -> UInt64? {
+        guard data.count == 8 else { return nil }
+        var value: UInt64 = 0
+        for byte in data { value = (value << 8) | UInt64(byte) }
+        return value
+    }
+
+    static func verify(signature: Data, over message: Data, publicKey: Data) -> Bool {
+        guard let key = try? Curve25519.Signing.PublicKey(rawRepresentation: publicKey) else {
+            return false
+        }
+        return key.isValidSignature(signature, for: message)
+    }
+}

bitchat/Protocols/Geohash.swift

@@ -0,0 +1,175 @@
+import Foundation
+
+/// Lightweight Geohash encoder used for Location Channels.
+/// Encodes latitude/longitude to base32 geohash with a fixed precision.
+enum Geohash {
+    private static let base32Chars = Array("0123456789bcdefghjkmnpqrstuvwxyz")
+    private static let base32Map: [Character: Int] = {
+        var map: [Character: Int] = [:]
+        for (i, c) in base32Chars.enumerated() { map[c] = i }
+        return map
+    }()
+
+    /// Validates a geohash string for building-level precision (8 characters).
+    /// - Parameter geohash: The geohash string to validate
+    /// - Returns: true if valid 8-character base32 geohash, false otherwise
+    static func isValidBuildingGeohash(_ geohash: String) -> Bool {
+        guard geohash.count == 8 else { return false }
+        return geohash.lowercased().allSatisfy { base32Map[$0] != nil }
+    }
+
+    /// Encodes the provided coordinates into a geohash string.
+    /// - Parameters:
+    ///   - latitude: Latitude in degrees (-90...90)
+    ///   - longitude: Longitude in degrees (-180...180)
+    ///   - precision: Number of geohash characters (2-12 typical). Values <= 0 return an empty string.
+    /// - Returns: Base32 geohash string of length `precision`.
+    static func encode(latitude: Double, longitude: Double, precision: Int) -> String {
+        guard precision > 0 else { return "" }
+
+        var latInterval: (Double, Double) = (-90.0, 90.0)
+        var lonInterval: (Double, Double) = (-180.0, 180.0)
+
+        var isEven = true
+        var bit = 0
+        var ch = 0
+        var geohash: [Character] = []
+
+        let lat = max(-90.0, min(90.0, latitude))
+        let lon = max(-180.0, min(180.0, longitude))
+
+        while geohash.count < precision {
+            if isEven {
+                let mid = (lonInterval.0 + lonInterval.1) / 2
+                if lon >= mid {
+                    ch |= (1 << (4 - bit))
+                    lonInterval.0 = mid
+                } else {
+                    lonInterval.1 = mid
+                }
+            } else {
+                let mid = (latInterval.0 + latInterval.1) / 2
+                if lat >= mid {
+                    ch |= (1 << (4 - bit))
+                    latInterval.0 = mid
+                } else {
+                    latInterval.1 = mid
+                }
+            }
+
+            isEven.toggle()
+            if bit < 4 {
+                bit += 1
+            } else {
+                geohash.append(base32Chars[ch])
+                bit = 0
+                ch = 0
+            }
+        }
+
+        return String(geohash)
+    }
+
+    /// Decodes a geohash into the center latitude/longitude of its bounding box.
+    /// - Parameter geohash: Base32 geohash string.
+    /// - Returns: (lat, lon) center coordinate.
+    static func decodeCenter(_ geohash: String) -> (lat: Double, lon: Double) {
+        var latInterval: (Double, Double) = (-90.0, 90.0)
+        var lonInterval: (Double, Double) = (-180.0, 180.0)
+
+        var isEven = true
+        for ch in geohash.lowercased() {
+            guard let cd = base32Map[ch] else { continue }
+            for mask in [16, 8, 4, 2, 1] {
+                if isEven {
+                    let mid = (lonInterval.0 + lonInterval.1) / 2
+                    if (cd & mask) != 0 { lonInterval.0 = mid } else { lonInterval.1 = mid }
+                } else {
+                    let mid = (latInterval.0 + latInterval.1) / 2
+                    if (cd & mask) != 0 { latInterval.0 = mid } else { latInterval.1 = mid }
+                }
+                isEven.toggle()
+            }
+        }
+        let lat = (latInterval.0 + latInterval.1) / 2
+        let lon = (lonInterval.0 + lonInterval.1) / 2
+        return (lat, lon)
+    }
+
+    /// Decodes a geohash into its latitude and longitude bounds.
+    /// - Parameter geohash: Base32 geohash string.
+    /// - Returns: (latMin, latMax, lonMin, lonMax)
+    static func decodeBounds(_ geohash: String) -> (latMin: Double, latMax: Double, lonMin: Double, lonMax: Double) {
+        var latInterval: (Double, Double) = (-90.0, 90.0)
+        var lonInterval: (Double, Double) = (-180.0, 180.0)
+
+        var isEven = true
+        for ch in geohash.lowercased() {
+            guard let cd = base32Map[ch] else { continue }
+            for mask in [16, 8, 4, 2, 1] {
+                if isEven {
+                    let mid = (lonInterval.0 + lonInterval.1) / 2
+                    if (cd & mask) != 0 { lonInterval.0 = mid } else { lonInterval.1 = mid }
+                } else {
+                    let mid = (latInterval.0 + latInterval.1) / 2
+                    if (cd & mask) != 0 { latInterval.0 = mid } else { latInterval.1 = mid }
+                }
+                isEven.toggle()
+            }
+        }
+        return (latInterval.0, latInterval.1, lonInterval.0, lonInterval.1)
+    }
+
+    /// Returns all 8 neighboring geohash cells at the same precision.
+    /// - Parameter geohash: Base32 geohash string.
+    /// - Returns: Array of 8 neighboring geohashes (N, NE, E, SE, S, SW, W, NW order).
+    static func neighbors(of geohash: String) -> [String] {
+        guard !geohash.isEmpty else { return [] }
+
+        let precision = geohash.count
+        let bounds = decodeBounds(geohash)
+        let center = decodeCenter(geohash)
+
+        // Calculate cell dimensions
+        let latHeight = bounds.latMax - bounds.latMin
+        let lonWidth = bounds.lonMax - bounds.lonMin
+
+        // Helper to wrap longitude around ±180
+        func wrapLongitude(_ lon: Double) -> Double {
+            var wrapped = lon
+            while wrapped > 180.0 { wrapped -= 360.0 }
+            while wrapped < -180.0 { wrapped += 360.0 }
+            return wrapped
+        }
+
+        // Helper to clamp latitude to ±90
+        func clampLatitude(_ lat: Double) -> Double {
+            return max(-90.0, min(90.0, lat))
+        }
+
+        // Calculate 8 neighbor centers
+        let neighbors: [(lat: Double, lon: Double)] = [
+            (center.lat + latHeight, center.lon),                    // N
+            (center.lat + latHeight, center.lon + lonWidth),         // NE
+            (center.lat, center.lon + lonWidth),                     // E
+            (center.lat - latHeight, center.lon + lonWidth),         // SE
+            (center.lat - latHeight, center.lon),                    // S
+            (center.lat - latHeight, center.lon - lonWidth),         // SW
+            (center.lat, center.lon - lonWidth),                     // W
+            (center.lat + latHeight, center.lon - lonWidth)          // NW
+        ]
+
+        // Encode each neighbor, handling boundary conditions
+        return neighbors.compactMap { neighbor in
+            let lat = clampLatitude(neighbor.lat)
+            let lon = wrapLongitude(neighbor.lon)
+
+            // Skip if we've crossed a pole (latitude clamped to boundary)
+            if (neighbor.lat > 90.0 || neighbor.lat < -90.0) {
+                return nil
+            }
+
+            return encode(latitude: lat, longitude: lon, precision: precision)
+        }
+    }
+}

bitchat/Protocols/LocationChannel.swift

@@ -0,0 +1,133 @@
+import Foundation
+
+/// Levels of location channels mapped to geohash precisions.
+enum GeohashChannelLevel: CaseIterable, Codable, Equatable {
+    case building
+    case block
+    case neighborhood
+    case city
+    case province   // previously .region
+    case region     // previously .country
+
+    /// Geohash length used for this level.
+    var precision: Int {
+        switch self {
+        case .building: return 8
+        case .block: return 7
+        case .neighborhood: return 6
+        case .city: return 5
+        case .province: return 4
+        case .region: return 2
+        }
+    }
+
+    var displayName: String {
+        switch self {
+        case .building:
+            return String(localized: "location_levels.building", comment: "Name for building-level location channel")
+        case .block:
+            return String(localized: "location_levels.block", comment: "Name for block-level location channel")
+        case .neighborhood:
+            return String(localized: "location_levels.neighborhood", comment: "Name for neighborhood-level location channel")
+        case .city:
+            return String(localized: "location_levels.city", comment: "Name for city-level location channel")
+        case .province:
+            return String(localized: "location_levels.province", comment: "Name for province-level location channel")
+        case .region:
+            return String(localized: "location_levels.region", comment: "Name for region-level location channel")
+        }
+    }
+}
+// Backward-compatible Codable for renamed cases
+extension GeohashChannelLevel {
+    init(from decoder: Decoder) throws {
+        let container = try decoder.singleValueContainer()
+        if let raw = try? container.decode(String.self) {
+            switch raw {
+            case "building": self = .building
+            case "block": self = .block
+            case "neighborhood": self = .neighborhood
+            case "city": self = .city
+            case "region": self = .province      // old "region" maps to new .province
+            case "country": self = .region       // old "country" maps to new .region
+            case "province": self = .province
+            default:
+                self = .block
+            }
+        } else if let precision = try? container.decode(Int.self) {
+            switch precision {
+            case 8: self = .building
+            case 7: self = .block
+            case 6: self = .neighborhood
+            case 5: self = .city
+            case 4: self = .province
+            case 0...3: self = .region
+            default: self = .block
+            }
+        } else {
+            self = .block
+        }
+    }
+
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.singleValueContainer()
+        switch self {
+        case .building: try container.encode("building")
+        case .block: try container.encode("block")
+        case .neighborhood: try container.encode("neighborhood")
+        case .city: try container.encode("city")
+        case .province: try container.encode("province")
+        case .region: try container.encode("region")
+        }
+    }
+}
+
+/// A computed geohash channel option.
+struct GeohashChannel: Codable, Equatable, Hashable, Identifiable {
+    let level: GeohashChannelLevel
+    let geohash: String
+
+    var id: String { "\(level)-\(geohash)" }
+
+    var displayName: String {
+        "\(level.displayName) • \(geohash)"
+    }
+}
+
+/// Identifier for current public chat channel (mesh or a location geohash).
+enum ChannelID: Equatable, Codable {
+    case mesh
+    case location(GeohashChannel)
+
+    /// Human readable name for UI.
+    var displayName: String {
+        switch self {
+        case .mesh:
+            return "Mesh"
+        case .location(let ch):
+            return ch.displayName
+        }
+    }
+
+    /// Nostr tag value for scoping (geohash), if applicable.
+    var nostrGeohashTag: String? {
+        switch self {
+        case .mesh: return nil
+        case .location(let ch): return ch.geohash
+        }
+    }
+    
+    var isMesh: Bool {
+        switch self {
+        case .mesh:     true
+        case .location: false
+        }
+    }
+    
+    var isLocation: Bool {
+        switch self {
+        case .mesh:     false
+        case .location: true
+        }
+    }
+}

bitchat/Protocols/NostrCarrierPacket.swift

@@ -0,0 +1,136 @@
+//
+// NostrCarrierPacket.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import BitFoundation
+import Foundation
+
+/// Wire payload for `MessageType.nostrCarrier` (0x28): a complete, signed
+/// Nostr event ferried over the mesh between a mesh-only peer and an
+/// internet gateway peer.
+///
+/// - `toGateway` rides a DIRECTED packet (recipientID = the gateway peer):
+///   a mesh-only sender asks the gateway to publish its locally signed
+///   geohash event to Nostr relays.
+/// - `fromGateway` rides a BROADCAST packet (default TTL): the gateway
+///   rebroadcasts inbound relay events so mesh-only peers see the channel.
+///
+/// The carried event is public geohash chat — already plaintext on Nostr —
+/// so the carrier adds no encryption. It IS signed by the originator's
+/// per-geohash identity, so neither the gateway nor any mesh relay can forge
+/// or alter it undetected: gateways and receivers verify the Schnorr
+/// signature before acting on it.
+///
+/// TLV encoding with 2-byte big-endian lengths (the event JSON exceeds the
+/// 1-byte TLV range used by smaller packets). Unknown TLV types are skipped
+/// for forward compatibility.
+struct NostrCarrierPacket: Equatable {
+    enum Direction: UInt8 {
+        case toGateway = 0x01
+        case fromGateway = 0x02
+    }
+
+    let direction: Direction
+    let geohash: String
+    /// Complete signed Nostr event JSON (id, pubkey, created_at, kind, tags,
+    /// content, sig).
+    let eventJSON: Data
+
+    /// BLE airtime cap for a carried event.
+    static let maxEventJSONBytes = 16 * 1024
+    static let maxGeohashLength = 12
+
+    private enum TLVType: UInt8 {
+        case direction = 0x01
+        case geohash = 0x02
+        case eventJSON = 0x03
+    }
+
+    init?(direction: Direction, geohash: String, eventJSON: Data) {
+        let geohashBytes = Data(geohash.utf8)
+        guard !geohashBytes.isEmpty,
+              geohashBytes.count <= Self.maxGeohashLength,
+              !eventJSON.isEmpty,
+              eventJSON.count <= Self.maxEventJSONBytes else {
+            return nil
+        }
+        self.direction = direction
+        self.geohash = geohash
+        self.eventJSON = eventJSON
+    }
+
+    init?(direction: Direction, geohash: String, event: NostrEvent) {
+        guard let json = try? event.jsonString(), !json.isEmpty else { return nil }
+        self.init(direction: direction, geohash: geohash, eventJSON: Data(json.utf8))
+    }
+
+    /// Decodes the carried event. Callers MUST still verify
+    /// `event.isValidSignature()` before publishing or displaying it.
+    func event() -> NostrEvent? {
+        guard let dict = try? JSONSerialization.jsonObject(with: eventJSON) as? [String: Any] else {
+            return nil
+        }
+        return try? NostrEvent(from: dict)
+    }
+
+    func encode() -> Data? {
+        var data = Data()
+        data.reserveCapacity(eventJSON.count + geohash.utf8.count + 12)
+
+        func appendTLV(_ type: TLVType, _ value: Data) {
+            data.append(type.rawValue)
+            data.append(UInt8((value.count >> 8) & 0xFF))
+            data.append(UInt8(value.count & 0xFF))
+            data.append(value)
+        }
+
+        appendTLV(.direction, Data([direction.rawValue]))
+        appendTLV(.geohash, Data(geohash.utf8))
+        appendTLV(.eventJSON, eventJSON)
+        return data
+    }
+
+    static func decode(_ data: Data) -> NostrCarrierPacket? {
+        // Defensive slice re-base (Data slices keep parent indices).
+        let data = Data(data)
+        var offset = 0
+        var direction: Direction?
+        var geohash: String?
+        var eventJSON: Data?
+
+        while offset + 3 <= data.count {
+            let typeRaw = data[offset]
+            let length = (Int(data[offset + 1]) << 8) | Int(data[offset + 2])
+            offset += 3
+            guard offset + length <= data.count else { return nil }
+            let value = data.subdata(in: offset..<offset + length)
+            offset += length
+
+            switch TLVType(rawValue: typeRaw) {
+            case .direction:
+                guard value.count == 1, let parsed = Direction(rawValue: value[0]) else { return nil }
+                direction = parsed
+            case .geohash:
+                guard let parsed = String(data: value, encoding: .utf8) else { return nil }
+                geohash = parsed
+            case .eventJSON:
+                eventJSON = value
+            case nil:
+                // Unknown TLV; skip (tolerant decoder for forward compatibility).
+                continue
+            }
+        }
+
+        guard offset == data.count,
+              let direction,
+              let geohash,
+              let eventJSON else {
+            return nil
+        }
+        return NostrCarrierPacket(direction: direction, geohash: geohash, eventJSON: eventJSON)
+    }
+}

bitchat/Protocols/Packets.swift

@@ -0,0 +1,192 @@
+import BitFoundation
+import Foundation
+
+// MARK: - Protocol TLV Packets
+
+struct AnnouncementPacket {
+    let nickname: String
+    let noisePublicKey: Data            // Noise static public key (Curve25519.KeyAgreement)
+    let signingPublicKey: Data          // Ed25519 public key for signing
+    let directNeighbors: [Data]?        // 8-byte peer IDs
+    let capabilities: PeerCapabilities? // advertised feature bits; nil when absent (old clients)
+
+    init(
+        nickname: String,
+        noisePublicKey: Data,
+        signingPublicKey: Data,
+        directNeighbors: [Data]?,
+        capabilities: PeerCapabilities? = nil
+    ) {
+        self.nickname = nickname
+        self.noisePublicKey = noisePublicKey
+        self.signingPublicKey = signingPublicKey
+        self.directNeighbors = directNeighbors
+        self.capabilities = capabilities
+    }
+
+    private enum TLVType: UInt8 {
+        case nickname = 0x01
+        case noisePublicKey = 0x02
+        case signingPublicKey = 0x03
+        case directNeighbors = 0x04
+        case capabilities = 0x05
+    }
+
+    func encode() -> Data? {
+        var data = Data()
+        // Reserve: TLVs for nickname (2 + n), noise key (2 + 32), signing key (2 + 32)
+        data.reserveCapacity(2 + min(nickname.count, 255) + 2 + noisePublicKey.count + 2 + signingPublicKey.count)
+
+        // TLV for nickname
+        guard let nicknameData = nickname.data(using: .utf8), nicknameData.count <= 255 else { return nil }
+        data.append(TLVType.nickname.rawValue)
+        data.append(UInt8(nicknameData.count))
+        data.append(nicknameData)
+
+        // TLV for noise public key
+        guard noisePublicKey.count <= 255 else { return nil }
+        data.append(TLVType.noisePublicKey.rawValue)
+        data.append(UInt8(noisePublicKey.count))
+        data.append(noisePublicKey)
+
+        // TLV for signing public key
+        guard signingPublicKey.count <= 255 else { return nil }
+        data.append(TLVType.signingPublicKey.rawValue)
+        data.append(UInt8(signingPublicKey.count))
+        data.append(signingPublicKey)
+        
+        // TLV for direct neighbors (optional)
+        if let neighbors = directNeighbors, !neighbors.isEmpty {
+            let neighborsData = neighbors.prefix(10).reduce(Data()) { $0 + $1 }
+            if !neighborsData.isEmpty && neighborsData.count % 8 == 0 {
+                data.append(TLVType.directNeighbors.rawValue)
+                data.append(UInt8(neighborsData.count))
+                data.append(neighborsData)
+            }
+        }
+
+        // TLV for capabilities (optional)
+        if let capabilities = capabilities {
+            let capabilityBytes = capabilities.encoded()
+            guard capabilityBytes.count <= 255 else { return nil }
+            data.append(TLVType.capabilities.rawValue)
+            data.append(UInt8(capabilityBytes.count))
+            data.append(capabilityBytes)
+        }
+
+        return data
+    }
+
+    static func decode(from data: Data) -> AnnouncementPacket? {
+        var offset = 0
+        var nickname: String?
+        var noisePublicKey: Data?
+        var signingPublicKey: Data?
+        var directNeighbors: [Data]?
+        var capabilities: PeerCapabilities?
+
+        while offset + 2 <= data.count {
+            let typeRaw = data[offset]
+            offset += 1
+            let length = Int(data[offset])
+            offset += 1
+
+            guard offset + length <= data.count else { return nil }
+            let value = data[offset..<offset + length]
+            offset += length
+
+            if let type = TLVType(rawValue: typeRaw) {
+                switch type {
+                case .nickname:
+                    nickname = String(data: value, encoding: .utf8)
+                case .noisePublicKey:
+                    noisePublicKey = Data(value)
+                case .signingPublicKey:
+                    signingPublicKey = Data(value)
+                case .directNeighbors:
+                    if length > 0 && length % 8 == 0 {
+                        var neighbors = [Data]()
+                        let count = length / 8
+                        for i in 0..<count {
+                            let start = value.startIndex + i * 8
+                            let end = start + 8
+                            neighbors.append(Data(value[start..<end]))
+                        }
+                        directNeighbors = neighbors
+                    }
+                case .capabilities:
+                    capabilities = PeerCapabilities(encoded: Data(value))
+                }
+            } else {
+                // Unknown TLV; skip (tolerant decoder for forward compatibility)
+                continue
+            }
+        }
+
+        guard let nickname = nickname, let noisePublicKey = noisePublicKey, let signingPublicKey = signingPublicKey else { return nil }
+        return AnnouncementPacket(
+            nickname: nickname,
+            noisePublicKey: noisePublicKey,
+            signingPublicKey: signingPublicKey,
+            directNeighbors: directNeighbors,
+            capabilities: capabilities
+        )
+    }
+}
+
+struct PrivateMessagePacket {
+    let messageID: String
+    let content: String
+
+    private enum TLVType: UInt8 {
+        case messageID = 0x00
+        case content = 0x01
+    }
+
+    func encode() -> Data? {
+        var data = Data()
+        data.reserveCapacity(2 + min(messageID.count, 255) + 2 + min(content.count, 255))
+
+        // TLV for messageID
+        guard let messageIDData = messageID.data(using: .utf8), messageIDData.count <= 255 else { return nil }
+        data.append(TLVType.messageID.rawValue)
+        data.append(UInt8(messageIDData.count))
+        data.append(messageIDData)
+
+        // TLV for content
+        guard let contentData = content.data(using: .utf8), contentData.count <= 255 else { return nil }
+        data.append(TLVType.content.rawValue)
+        data.append(UInt8(contentData.count))
+        data.append(contentData)
+
+        return data
+    }
+
+    static func decode(from data: Data) -> PrivateMessagePacket? {
+        var offset = 0
+        var messageID: String?
+        var content: String?
+
+        while offset + 2 <= data.count {
+            guard let type = TLVType(rawValue: data[offset]) else { return nil }
+            offset += 1
+
+            let length = Int(data[offset])
+            offset += 1
+
+            guard offset + length <= data.count else { return nil }
+            let value = data[offset..<offset + length]
+            offset += length
+
+            switch type {
+            case .messageID:
+                messageID = String(data: value, encoding: .utf8)
+            case .content:
+                content = String(data: value, encoding: .utf8)
+            }
+        }
+
+        guard let messageID = messageID, let content = content else { return nil }
+        return PrivateMessagePacket(messageID: messageID, content: content)
+    }
+}

bitchat/Protocols/PeerCapabilities+Local.swift

@@ -0,0 +1,11 @@
+import BitFoundation
+
+extension PeerCapabilities {
+    /// Capabilities this build advertises in its announce packets.
+    /// Each feature adds its bit here when it ships.
+    static let localSupported: PeerCapabilities = {
+        var caps: PeerCapabilities = [.prekeys, .vouch, .groups]
+        if TransportConfig.wifiBulkEnabled { caps.insert(.wifiBulk) }
+        return caps
+    }()
+}

bitchat/Protocols/VouchAttestation.swift

@@ -0,0 +1,225 @@
+//
+// VouchAttestation.swift
+// bitchat
+//
+// This is free and unencumbered software released into the public domain.
+// For more information, see <https://unlicense.org>
+//
+
+import CryptoKit
+import Foundation
+
+/// A signed statement that the *sender of the enclosing Noise payload* has
+/// verified the identity described here ("transitive verification").
+///
+/// The voucher's identity is deliberately implicit: attestations only travel
+/// inside an authenticated Noise session (`NoisePayloadType.vouch`), so the
+/// receiver verifies the Ed25519 signature against the session peer's
+/// announce-bound signing key and stores the vouch keyed by that peer's
+/// fingerprint. Nothing in the attestation names the voucher, so a captured
+/// attestation cannot be replayed by a third party whose signing key doesn't
+/// match.
+///
+/// Wire format — single attestation (TLV, 1-byte type + 1-byte length):
+/// - `0x01` voucheeFingerprint: 32 bytes, SHA-256 of the vouchee's Noise static key
+/// - `0x02` voucheeSigningKey: 32 bytes, Ed25519; anchors the vouch to a concrete identity
+/// - `0x03` timestamp: 8 bytes big-endian, milliseconds since 1970
+/// - `0x04` signature: 64 bytes, Ed25519 by the VOUCHER's signing key over
+///   `"bitchat-vouch-v1" | voucheeFingerprint | voucheeSigningKey | timestamp`
+///
+/// Unknown TLV types are skipped for forward compatibility.
+///
+/// Batch format (the `vouch` Noise payload body):
+/// `[count: UInt8]` then per attestation `[length: UInt16 BE][attestation TLV]`.
+struct VouchAttestation: Equatable {
+    static let signingContext = "bitchat-vouch-v1"
+    /// Receiver-side expiry for attestations.
+    static let maxAge: TimeInterval = 30 * 24 * 60 * 60
+    /// Tolerated clock skew for attestations timestamped in the future.
+    static let maxClockSkew: TimeInterval = 60 * 60
+    /// Upper bound of attestations carried/accepted in one batch payload.
+    static let maxBatchCount = 16
+
+    static let fingerprintSize = 32
+    static let signingKeySize = 32
+    static let signatureSize = 64
+
+    let voucheeFingerprint: Data  // 32 bytes
+    let voucheeSigningKey: Data   // 32 bytes
+    let timestampMs: UInt64
+    let signature: Data           // 64 bytes
+
+    private enum TLVType: UInt8 {
+        case voucheeFingerprint = 0x01
+        case voucheeSigningKey = 0x02
+        case timestamp = 0x03
+        case signature = 0x04
+    }
+
+    var voucheeFingerprintHex: String { voucheeFingerprint.hexEncodedString() }
+
+    var timestamp: Date { Date(timeIntervalSince1970: TimeInterval(timestampMs) / 1000) }
+
+    /// The exact bytes the voucher signs.
+    static func signableBytes(
+        voucheeFingerprint: Data,
+        voucheeSigningKey: Data,
+        timestampMs: UInt64
+    ) -> Data {
+        var message = Data(signingContext.utf8)
+        message.append(voucheeFingerprint)
+        message.append(voucheeSigningKey)
+        var timestampBE = timestampMs.bigEndian
+        withUnsafeBytes(of: &timestampBE) { message.append(contentsOf: $0) }
+        return message
+    }
+
+    var signableBytes: Data {
+        Self.signableBytes(
+            voucheeFingerprint: voucheeFingerprint,
+            voucheeSigningKey: voucheeSigningKey,
+            timestampMs: timestampMs
+        )
+    }
+
+    /// Builds and signs an attestation. `sign` is the voucher's Ed25519
+    /// signing primitive (e.g. `Transport.noiseSignData`).
+    static func build(
+        voucheeFingerprint: Data,
+        voucheeSigningKey: Data,
+        timestampMs: UInt64 = UInt64(Date().timeIntervalSince1970 * 1000),
+        sign: (Data) -> Data?
+    ) -> VouchAttestation? {
+        guard voucheeFingerprint.count == fingerprintSize,
+              voucheeSigningKey.count == signingKeySize else { return nil }
+        let message = signableBytes(
+            voucheeFingerprint: voucheeFingerprint,
+            voucheeSigningKey: voucheeSigningKey,
+            timestampMs: timestampMs
+        )
+        guard let signature = sign(message), signature.count == signatureSize else { return nil }
+        return VouchAttestation(
+            voucheeFingerprint: voucheeFingerprint,
+            voucheeSigningKey: voucheeSigningKey,
+            timestampMs: timestampMs,
+            signature: signature
+        )
+    }
+
+    /// Verifies the Ed25519 signature against the voucher's announce-bound
+    /// signing key.
+    func verifySignature(voucherSigningKey: Data) -> Bool {
+        guard let publicKey = try? Curve25519.Signing.PublicKey(rawRepresentation: voucherSigningKey) else {
+            return false
+        }
+        return publicKey.isValidSignature(signature, for: signableBytes)
+    }
+
+    /// Whether the attestation is outside its validity window (older than
+    /// `maxAge`, or timestamped implausibly far in the future).
+    func isExpired(now: Date = Date()) -> Bool {
+        let age = now.timeIntervalSince(timestamp)
+        return age > Self.maxAge || age < -Self.maxClockSkew
+    }
+
+    // MARK: - Encoding
+
+    func encode() -> Data? {
+        guard voucheeFingerprint.count == Self.fingerprintSize,
+              voucheeSigningKey.count == Self.signingKeySize,
+              signature.count == Self.signatureSize else { return nil }
+        var data = Data()
+        func appendTLV(_ type: TLVType, _ value: Data) {
+            data.append(type.rawValue)
+            data.append(UInt8(value.count))
+            data.append(value)
+        }
+        appendTLV(.voucheeFingerprint, voucheeFingerprint)
+        appendTLV(.voucheeSigningKey, voucheeSigningKey)
+        var timestampBE = timestampMs.bigEndian
+        appendTLV(.timestamp, withUnsafeBytes(of: &timestampBE) { Data($0) })
+        appendTLV(.signature, signature)
+        return data
+    }
+
+    static func decode(from data: Data) -> VouchAttestation? {
+        var fingerprint: Data?
+        var signingKey: Data?
+        var timestampMs: UInt64?
+        var signature: Data?
+
+        var offset = data.startIndex
+        while offset < data.endIndex {
+            guard data.index(offset, offsetBy: 2, limitedBy: data.endIndex) != nil,
+                  offset + 1 < data.endIndex else { return nil }
+            let type = data[offset]
+            let length = Int(data[offset + 1])
+            let valueStart = offset + 2
+            guard let valueEnd = data.index(valueStart, offsetBy: length, limitedBy: data.endIndex) else {
+                return nil
+            }
+            let value = Data(data[valueStart..<valueEnd])
+            switch TLVType(rawValue: type) {
+            case .voucheeFingerprint:
+                guard value.count == fingerprintSize else { return nil }
+                fingerprint = value
+            case .voucheeSigningKey:
+                guard value.count == signingKeySize else { return nil }
+                signingKey = value
+            case .timestamp:
+                guard value.count == 8 else { return nil }
+                timestampMs = value.reduce(UInt64(0)) { ($0 << 8) | UInt64($1) }
+            case .signature:
+                guard value.count == signatureSize else { return nil }
+                signature = value
+            case nil:
+                break // Unknown TLV: skip for forward compatibility.
+            }
+            offset = valueEnd
+        }
+
+        guard let fingerprint, let signingKey, let timestampMs, let signature else { return nil }
+        return VouchAttestation(
+            voucheeFingerprint: fingerprint,
+            voucheeSigningKey: signingKey,
+            timestampMs: timestampMs,
+            signature: signature
+        )
+    }
+
+    // MARK: - Batch encoding
+
+    /// Encodes up to `maxBatchCount` attestations into one payload body.
+    static func encodeList(_ attestations: [VouchAttestation]) -> Data? {
+        guard !attestations.isEmpty, attestations.count <= maxBatchCount else { return nil }
+        var data = Data()
+        data.append(UInt8(attestations.count))
+        for attestation in attestations {
+            guard let encoded = attestation.encode(), encoded.count <= Int(UInt16.max) else { return nil }
+            var lengthBE = UInt16(encoded.count).bigEndian
+            withUnsafeBytes(of: &lengthBE) { data.append(contentsOf: $0) }
+            data.append(encoded)
+        }
+        return data
+    }
+
+    /// Decodes a batch payload, dropping malformed entries and ignoring
+    /// anything beyond `maxBatchCount` (sender-declared count is not trusted).
+    static func decodeList(from data: Data) -> [VouchAttestation] {
+        guard data.count > 1 else { return [] }
+        let declaredCount = Int(data[data.startIndex])
+        let limit = min(declaredCount, maxBatchCount)
+        var attestations: [VouchAttestation] = []
+        var offset = data.startIndex + 1
+        while attestations.count < limit, offset < data.endIndex {
+            guard let lengthEnd = data.index(offset, offsetBy: 2, limitedBy: data.endIndex) else { break }
+            let length = Int(data[offset]) << 8 | Int(data[offset + 1])
+            guard let entryEnd = data.index(lengthEnd, offsetBy: length, limitedBy: data.endIndex) else { break }
+            if let attestation = decode(from: Data(data[lengthEnd..<entryEnd])) {
+                attestations.append(attestation)
+            }
+            offset = entryEnd
+        }
+        return attestations
+    }
+}