496972dcc9
* Mesh robustness: link-aware fragmentation, relay jitter, connection budget, adaptive scanning; fix BLE queue deadlock - Link-aware fragmentation using per-link write/notify limits - Directed fragments for one-to-one; exclude from relays - Add relay jitter with cancel-on-duplicate to reduce floods - Cap central links and rate-limit connect attempts with queue - Foreground duty-cycled scanning when connected; continuous when isolated - Fix deadlock by avoiding sync on BLE queue when already on it - Silence Keychain var->let warnings * Mesh: add relay jitter; dynamic RSSI threshold; candidate scoring/backoff; fix misplaced lines in BLEService extension * macOS UI: restore mesh peer list when geohash feature is iOS-only by moving mesh list outside iOS switch (ContentView) * ContentView: add macOS mesh peer list under #else to fix missing People section on macOS * Refactor People section: extract MeshPeerList and GeohashPeopleList into separate views to reduce SwiftUI type-checking complexity; integrate in ContentView * BLE: prevent re-fragmentation loops; UI: darker mesh blue + first-row spacing in peer list * Mesh flood/battery: probabilistic relays, adaptive TTL caps, fragment pacing + scan pause, assembly cap; enable relayed DMs with direct-first then flood fallback. * Refactor BLEService broadcast: split pad policy, encrypted/direct-first handler, and link-aware sender; simplify broadcastPacket to delegate by type. * Extract relay decision into RelayController with RelayDecision; simplify handleReceivedPacket to use it. * Move RelayController and RelayDecision into their own file under Services; keep BLEService leaner. * UI: adjust mesh blue to a darker, less purple tone; apply consistently for count and #mesh badge. * Project: include RelayController.swift in target and sync project file changes. --------- Co-authored-by: jack <jackjackbits@users.noreply.github.com>
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.
Warning
Private messages 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 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 file for details.
Features
- Decentralized Mesh Network: Automatic peer discovery and multi-hop message relay over Bluetooth LE
- Privacy First: No accounts, no phone numbers, no persistent identifiers
- Private Message End-to-End Encryption: Noise Protocol
- IRC-Style Commands: Familiar
/slap,/msg,/whostyle 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
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
Mesh Networking
- Each device acts as both client and peripheral
- Automatic peer discovery and connection management
- Adaptive duty cycling for battery optimization
For detailed protocol documentation, see the Technical Whitepaper.
Setup
Option 1: Using XcodeGen (Recommended)
-
Install XcodeGen if you haven't already:
brew install xcodegen -
Generate the Xcode project:
cd bitchat xcodegen generate -
Open the generated project:
open bitchat.xcodeproj
Option 2: Using Swift Package Manager
-
Open the project in Xcode:
cd bitchat open Package.swift -
Select your target device and run
Option 3: Manual Xcode Project
- Open Xcode and create a new iOS/macOS App
- Copy all Swift files from the
bitchatdirectory into your project - Update Info.plist with Bluetooth permissions
- 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.
Run just clean afterwards to restore things to original state for mobile app building and development.