c1ce9029d8
Tier 3 of a protest-hardening review. The BLE mesh is already properly fenced off from network reachability and needs nothing here; every gap is on the internet side, or in how someone gets a build they can trust. Say when Tor is blocked. The bootstrap poll loop simply ended at its 75-second deadline, leaving isStarting true with no further state, so a network that blocks Tor was indistinguishable from a slow one and the UI said "starting tor…" indefinitely. TorManager now exposes bootstrapDidStall and posts .TorBootstrapDidStall, and the app reports that mesh messaging still works while internet delivery is paused. It is cleared on each new start or restart, so a later attempt can report again. Let relays be added by hand. The four built-in relays are well-known clearnet hostnames, which is four names for a censor to block and no recourse short of a new build. NostrRelaySettings persists up to eight additional relays, normalized, .onion accepted, with a settings editor. They join the same target set as the built-ins and are subject to the same activation policy. Removal reconciles against the previous set: the teardown path iterates the current targets, so without that a removed relay's socket and queued sends would linger — covered by a test that fails without it. The merged list is cached rather than recomputed, because allowedRelayList consults it once per candidate URL and would otherwise read UserDefaults inside that loop. Stop stranding people who denied location. The activation gate required location permission or a mutual favorite, but teleporting into a geohash requires neither, so someone with no permission and no favorites could sit in a channel that never connected while Tor and the relays stayed suppressed and nothing said why. Being in a location channel is now a third arm of the gate, in both the activation service and the relay manager's copy of the policy, and leaving the channel closes it again. Stop burning the Tor timeout when Tor is off. GeoRelayDirectory awaited Tor readiness unconditionally, but with the preference off TorManager has been shut down, so every refresh spent the full bootstrap deadline and the directory froze on its cached copy. It now keys on the preference, not on live readiness: Tor wanted but unavailable must still skip the fetch rather than fall back to clearnet. Say what turning Tor off costs. The toggle's copy described it as hiding your IP "for location channels", understating both scope and consequence. It now names private messages too, and while the toggle is off the settings screen states that every relay can see the device IP. Make builds verifiable. There was no release verification of any kind: no signatures, no checksums, no documented procedure. Post-takedown that is the acute gap, because mirrors appear and people install whatever they can find during a shutdown. source-manifest.yml publishes a per-tag SHA-256 manifest with a provenance attestation, self-checking before it publishes, and docs/VERIFYING-A-BUILD.md explains how to verify source and states plainly that compiled builds from anywhere but the App Store cannot be verified. It also records the gaps honestly: no published signing key, no reproducible build, no non-GitHub mirror. docs/TOR-INTEGRATION.md was substantially stale — it documented a torrc, SOCKSPort and ControlPort that the in-process Arti client does not use, and claimed there are no user-visible settings — so it is rewritten, including the deferred gap below. Deferred: no Tor bridges or pluggable transports. arti-client is built without pt-client or bridge-client and bootstraps from stock config, so in a country that blocks Tor outright there is still no circumvention path — only a clear report that there isn't. Closing it needs the Rust features, bridge config through the FFI, and an xcframework rebuild under the pinned toolchain with a provenance update, which is its own change. Co-authored-by: jack <jackjackbits@users.noreply.github.com> Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
7.2 KiB
bitchat
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.
Getting a copy you can trust
Install from the App Store, or build from source you have verified. A compiled build from anywhere else cannot be verified — see Verifying bitchat for how to check source against the per-release hash manifest, and for what to do if that is the only build you can get.
This matters more than it usually would: this repository has been the target of takedown demands, and when a repository or releases page disappears, mirrors appear that nobody can check.
License
This project is released into the public domain. See the 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 servers. Note that the mesh does use a persistent per-device identifier derived from your identity key — see the whitepaper on identity and metadata for what a nearby radio can observe
- Private Message End-to-End Encryption: Noise Protocol for mesh, BitChat private envelopes for Nostr fallback
- 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
BitChat uses a hybrid messaging architecture with two complementary transport layers:
Bluetooth Mesh Network (Offline)
- 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 for live sessions (store-and-forward mail is sealed without it — see the whitepaper)
- 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
- BitChat Private Envelopes: App-specific encrypted private messages over Nostr relays
- Ephemeral Keys: Fresh cryptographic identity per geohash area
BitChat's private-envelope format is proprietary and is not NIP-17,
NIP-44, or NIP-59 compatible. It uses Nostr as a relay transport but only
interoperates with BitChat clients: private payloads travel inside kind-1059
events whose v2:-prefixed content is a BitChat-specific XChaCha20-Poly1305
construction, not NIP-44 encryption.
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 levelneighborhood(6 chars): District/neighborhoodcity(5 chars): City levelprovince(4 chars): State/provinceregion(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:
-
Bluetooth First (preferred when available)
- Direct connection with established Noise session
- Fastest and most private option
-
Nostr Fallback (when Bluetooth unavailable)
- Uses recipient's Nostr public key
- BitChat's app-specific private-envelope encryption
- Routes through global relay network
-
Smart Queuing (when neither available)
- Messages queued until transport becomes available
- Automatic delivery when connection established
For detailed protocol documentation, see the Technical Whitepaper.
Setup
Option 1: Using Xcode
open bitchat.xcodeproj
For a signed device build, create your ignored local configuration and replace the example team ID with your Apple Developer Team ID:
cp Configs/Local.xcconfig.example Configs/Local.xcconfig
Local.xcconfig.example derives unique app and App Group identifiers from that
team ID. The entitlement files already reference $(APP_GROUP_ID), so tracked
project or entitlement files do not need to be edited.
Useful command-line checks from the repository root:
# macOS Debug build without signing
xcodebuild -project bitchat.xcodeproj -scheme "bitchat (macOS)" \
-configuration Debug CODE_SIGNING_ALLOWED=NO build
# Full SwiftPM test suite
swift test
# iOS simulator tests
xcodebuild -project bitchat.xcodeproj -scheme "bitchat (iOS)" \
-sdk iphonesimulator \
-destination 'platform=iOS Simulator,name=iPhone 17' test
If iPhone 17 is unavailable, choose an installed simulator from:
xcodebuild -showdestinations -project bitchat.xcodeproj -scheme "bitchat (iOS)"
Option 2: Using just
brew install just
just check
just run
just build and just run use the current bitchat (macOS) scheme and keep
Xcode output in the ignored .DerivedData/ directory. They never patch source,
project, configuration, or entitlement files.
just clean removes only .DerivedData/ and .build/. It does not invoke Git
or restore tracked files, so uncommitted work is preserved. just test runs the
SwiftPM suite and just test-ios runs the iPhone 17 simulator suite.
Localization
- App localizations live in
bitchat/Localizable.xcstrings. - Share extension strings are separate in
bitchatShareExtension/Localization/Localizable.xcstrings. - 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 buildto compile-check any localization updates.