e6903456ab
* NIP-17/44: adopt NIP-44 v2 (XChaCha20-Poly1305, v2: base64url), switch rumor kind to 14, randomize BIP-340 aux; add XChaCha20Poly1305Compat and wire-up * Nostr DMs: ensure delivered/read acks are sent even without Noise key mapping by falling back to direct Nostr (geohash-style) acks to sender pubkey * NIP-44 v2 decrypt: try both Y parities for x-only sender pubkeys (even then odd) to fix unwrap authentication failures * Tests: add NIP-44 v2 ACK round-trip tests (delivered/read) using bitchat1 embedding and gift-wrap decrypt path * UI: fix DM autoscroll IDs by using dm:<peer>|<id> for private chat item IDs and preserve anchors, ensuring scrollTo targets exist when opening/switching/new messages * UI: fix string interpolation in DM/geohash context keys (remove escaped interpolation) to resolve 'unused ch' warnings and ensure proper IDs * UI: MeshPeerList shows transport state icon: radio for mesh-connected, purple globe for mutual favorite/Nostr; fallback dim person for others --------- 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.