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809e222a31
* Remove sequence numbers from protocol - Remove sequenceNumber field from BitchatPacket struct - Update BinaryProtocol to not encode/decode sequence numbers (header size reduced from 17 to 13 bytes) - Replace sequence-based duplicate detection with content-based using packet ID hash - Update packet ID generation to use SHA256(senderID + timestamp + type + payload prefix) - Remove all sequence tracking variables and methods - Simplify duplicate detection to rely on timestamp and content hashing * Fix connection stability issues - Increase peer availability check interval from 5 to 15 seconds - Fix availability logic to not mark connected peers as unavailable - Add BLE connection keepalive timer (20s) to prevent iOS timeouts - Fix missing delivery ACKs by passing peripheral context through Noise decryption - Reduce identity announce frequency from 2 to 10 seconds minimum - Remove unnecessary identity announces on connection - Debounce identity cache keychain saves (2 second delay) - Add message retry notification handler in ChatViewModel - Fix version negotiation redundancy by checking existing negotiations - Keep Noise sessions for already-connected peers * Fix build errors in message retry handler - Fix reference to 'displayedMessages' - should be 'messages' - Fix sendMessage call signature to use individual parameters instead of message object - Both iOS and macOS builds now succeed * Fix remaining connection stability issues - Fix duplicate identity announces with content-based deduplication - Simplify peripheral mapping with cleaner temp ID to peer ID transitions - Improve graceful leave detection across peer ID rotations - Track previousPeerID from announcements to maintain state - Add time-based cleanup for gracefully left peers * Fix connection stability issues - Add special duplicate detection for identity announces - Simplify peripheral mapping with dedicated structure - Improve graceful leave detection with peer ID rotation handling - Track graceful leave timestamps for cleanup - Transfer states properly during peer ID rotation * Improve BLE connection stability and message reliability - Increase peer availability timeout from 5s to 15s to prevent flapping - Add BLE keepalive timer with 30s interval to maintain connections - Fix missing delivery ACKs by passing peripheral context through decryption - Reduce identity announce frequency from 2s to 10s minimum interval - Add keychain save debouncing with 2s delay to prevent excessive writes - Implement message retry system for failed deliveries to favorites - Fix version negotiation redundancy by checking existing state - Add special duplicate detection for identity announcements - Implement graceful leave detection with peer ID rotation support - Simplify peripheral mapping to reduce complexity - Fix switch statement structure issues causing build errors These changes significantly improve connection stability, eliminate peer availability flapping, and ensure reliable message delivery. --------- 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 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 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
- Cover Traffic: Timing obfuscation and dummy messages for enhanced privacy
- Private Message End-to-End Encryption: Noise Protocol
- Store & Forward: Messages cached for offline peers and delivered when they reconnect
- IRC-Style Commands: Familiar
/join,/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
- Store-and-forward for offline message delivery
- 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.