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A secure, decentralized, peer-to-peer messaging app that works over Bluetooth mesh networks. No internet required, no servers, no phone numbers - just pure encrypted communication.

This is the Android port of the original bitchat iOS app, maintaining 100% protocol compatibility for cross-platform communication.

You can download the latest version of bitchat for Android from the GitHub Releases page.

Instructions:

1. Download the APK: On your Android device, navigate to the link above and download the latest .apk file. Open it.
2. Allow Unknown Sources: On some devices, before you can install the APK, you may need to enable "Install from unknown sources" in your device's settings. This is typically found under Settings > Security or Settings > Apps & notifications > Special app access.
3. Install: Open the downloaded .apk file to begin the installation.

This project is released into the public domain. See the LICENSE file for details.

• ✅ Cross-Platform Compatible: Full protocol compatibility with iOS bitchat
• ✅ Decentralized Mesh Network: Automatic peer discovery and multi-hop message relay over Bluetooth LE
• ✅ End-to-End Encryption: X25519 key exchange + AES-256-GCM for private messages
• ✅ Channel-Based Chats: Topic-based group messaging with optional password protection
• ✅ Store & Forward: Messages cached for offline peers and delivered when they reconnect
• ✅ Privacy First: No accounts, no phone numbers, no persistent identifiers
• ✅ IRC-Style Commands: Familiar /join, /msg, /who style interface
• ✅ Message Retention: Optional channel-wide message saving controlled by channel owners
• ✅ Emergency Wipe: Triple-tap logo to instantly clear all data
• ✅ Modern Android UI: Jetpack Compose with Material Design 3
• ✅ Dark/Light Themes: Terminal-inspired aesthetic matching iOS version
• ✅ Battery Optimization: Adaptive scanning and power management

• Android Studio: Arctic Fox (2020.3.1) or newer
• Android SDK: API level 26 (Android 8.0) or higher
• Kotlin: 1.8.0 or newer
• Gradle: 7.0 or newer

1. Clone the repository:

   git clone github.com/permissionlesstech/bitchat-android.git cd bitchat-android

2. Open in Android Studio:

   # Open Android Studio and select "Open an Existing Project" # Navigate to the bitchat-android directory

3. Build the project:

   ./gradlew build

4. Install on device:

   ./gradlew installDebug

For development builds with debugging enabled:

./gradlew assembleDebug adb install -r app/build/outputs/apk/debug/app-debug.apk

For production releases:

./gradlew assembleRelease

The app requires the following permissions (automatically requested):

• Bluetooth: Core BLE functionality
• Location: Required for BLE scanning on Android
• Notifications: Message alerts and background updates

• Bluetooth LE (BLE): Required for mesh networking
• Android 8.0+: API level 26 minimum
• RAM: 2GB recommended for optimal performance

• /j #channel - Join or create a channel
• /m @name message - Send a private message
• /w - List online users
• /channels - Show all discovered channels
• /block @name - Block a peer from messaging you
• /block - List all blocked peers
• /unblock @name - Unblock a peer
• /clear - Clear chat messages
• /pass [password] - Set/change channel password (owner only)
• /transfer @name - Transfer channel ownership
• /save - Toggle message retention for channel (owner only)

1. Install the app on your Android device (requires Android 8.0+)
2. Grant permissions for Bluetooth and location when prompted
3. Launch bitchat - it will auto-start mesh networking
4. Set your nickname or use the auto-generated one
5. Connect automatically to nearby iOS and Android bitchat users
6. Join a channel with /j #general or start chatting in public
7. Messages relay through the mesh network to reach distant peers

• Jetpack Compose UI: Modern Material Design 3 interface
• Dark/Light Themes: Terminal-inspired aesthetic matching iOS
• Haptic Feedback: Vibrations for interactions and notifications
• Adaptive Layout: Optimized for various Android screen sizes
• Message Status: Real-time delivery and read receipts
• RSSI Indicators: Signal strength colors for each peer

• Password Protection: Channel owners can set passwords with /pass
• Message Retention: Owners can enable mandatory message saving with /save
• @ Mentions: Use @nickname to mention users (with autocomplete)
• Ownership Transfer: Pass control to trusted users with /transfer

• Private Messages: X25519 key exchange + AES-256-GCM encryption
• Channel Messages: Argon2id password derivation + AES-256-GCM
• Digital Signatures: Ed25519 for message authenticity
• Forward Secrecy: New key pairs generated each session

• No Registration: No accounts, emails, or phone numbers required
• Ephemeral by Default: Messages exist only in device memory
• Cover Traffic: Random delays and dummy messages prevent traffic analysis
• Emergency Wipe: Triple-tap logo to instantly clear all data
• Local-First: Works completely offline, no servers involved

• LZ4 Compression: Automatic compression for messages >100 bytes
• 30-70% bandwidth savings on typical text messages
• Smart compression: Skips already-compressed data

• Adaptive Power Modes: Automatically adjusts based on battery level
  • Performance mode: Full features when charging or >60% battery
  • Balanced mode: Default operation (30-60% battery)
  • Power saver: Reduced scanning when <30% battery
  • Ultra-low power: Emergency mode when <10% battery
• Background efficiency: Automatic power saving when app backgrounded
• Configurable scanning: Duty cycle adapts to battery state

• Optimized Bloom filters: Faster duplicate detection with less memory
• Message aggregation: Batches small messages to reduce transmissions
• Adaptive connection limits: Adjusts peer connections based on power mode

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

• 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

• Coroutine Architecture: Asynchronous operations for mesh networking
• Kotlin Coroutines: Thread-safe concurrent mesh operations
• EncryptedSharedPreferences: Secure storage for user settings
• Lifecycle-Aware: Proper handling of Android app lifecycle
• Battery Optimization: Foreground service and adaptive scanning

1. BitchatApplication.kt: Application-level initialization and dependency injection
2. MainActivity.kt: Main activity handling permissions and UI hosting
3. ChatViewModel.kt: MVVM pattern managing app state and business logic
4. BluetoothMeshService.kt: Core BLE mesh networking (central + peripheral roles)
5. EncryptionService.kt: Cryptographic operations using BouncyCastle
6. BinaryProtocol.kt: Binary packet encoding/decoding matching iOS format
7. ChatScreen.kt: Jetpack Compose UI with Material Design 3

• Jetpack Compose: Modern declarative UI
• BouncyCastle: Cryptographic operations (X25519, Ed25519, AES-GCM)
• Nordic BLE Library: Reliable Bluetooth LE operations
• Kotlin Coroutines: Asynchronous programming
• LZ4: Message compression (when enabled)
• EncryptedSharedPreferences: Secure local storage

The Android implementation maintains 100% binary protocol compatibility with iOS:

• Header Format: Identical 13-byte header structure
• Packet Types: Same message types and routing logic
• Encryption: Identical cryptographic algorithms and key exchange
• UUIDs: Same Bluetooth service and characteristic identifiers
• Fragmentation: Compatible message fragmentation for large content

1. Update version information:

   // In app/build.gradle.kts defaultConfig {     versionCode = 2  // Increment for each release     versionName = "1.1.0"  // User-visible version }

2. Create a signed release build:

   ./gradlew assembleRelease

3. Generate app bundle (recommended for Play Store):

   ./gradlew bundleRelease

• Target API: Latest Android API (currently 34)
• Privacy Policy: Required for apps requesting sensitive permissions
• App Permissions: Justify Bluetooth and location usage
• Content Rating: Complete questionnaire for age-appropriate content

• Google Play Store: Main distribution channel
• F-Droid: For open-source distribution
• Direct APK: For testing and development

This Android port enables seamless communication with the original iOS bitchat app:

• iPhone ↔ Android: Full bidirectional messaging
• Mixed Groups: iOS and Android users in same channels
• Feature Parity: All commands and encryption work across platforms
• Protocol Sync: Identical message format and routing behavior

iOS Version: For iPhone/iPad users, get the original bitchat at github.com/jackjackbits/bitchat

Contributions are welcome! Key areas for enhancement:

1. Performance: Battery optimization and connection reliability
2. UI/UX: Additional Material Design 3 features
3. Security: Enhanced cryptographic features
4. Testing: Unit and integration test coverage
5. Documentation: API documentation and development guides

• Bug Reports: Create an issue with device info and logs
• Feature Requests: Start a discussion
• Security Issues: Email security concerns privately
• iOS Compatibility: Cross-reference with original iOS repo

For iOS-specific issues, please refer to the original iOS bitchat repository.