Description
Warning This software has not received external security review and may contain vulnerabilities and may not necessarily meet its stated security goals. Do not use it for sensitive use cases, and do not rely on its security until it has been reviewed. Work in progress. bitchat for Android 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. Install bitchat You can download the latest version of bitchat for Android from the GitHub Releases page . Instructions: Download the APK: On your Android device, navigate to the link above and download the latest .apk file. Open it. 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 . Install: Open the downloaded .apk file to begin the installation. License This project is released into the public domain. See the LICENSE file for details. Features ✅ 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 Setup Prerequisites 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 Build Instructions Clone the repository: github.com/permissionlesstech/bitchat-android.git cd bitchat-android"> git clone github.com/permissionlesstech/bitchat-android.git cd bitchat-android Open in Android Studio: # Open Android Studio and select "Open an Existing Project" # Navigate to the bitchat-android directory Build the project: ./gradlew build Install on device: ./gradlew installDebug Development Build For development builds with debugging enabled: ./gradlew assembleDebug adb install -r app/build/outputs/apk/debug/app-debug.apk Release Build For production releases: ./gradlew assembleRelease Android-Specific Requirements Permissions 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 Hardware Requirements Bluetooth LE (BLE) : Required for mesh networking Android 8.0+ : API level 26 minimum RAM : 2GB recommended for optimal performance Usage Basic Commands /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) Getting Started Install the app on your Android device (requires Android 8.0+) Grant permissions for Bluetooth and location when prompted Launch bitchat - it will auto-start mesh networking Set your nickname or use the auto-generated one Connect automatically to nearby iOS and Android bitchat users Join a channel with /j #general or start chatting in public Messages relay through the mesh network to reach distant peers Android UI Features 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 Channel Features 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 Security & Privacy Encryption 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 Privacy Features 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 Performance & Efficiency Message Compression LZ4 Compression : Automatic compression for messages >100 bytes 30-70% bandwidth savings on typical text messages Smart compression : Skips already-compressed data Battery Optimization 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 Network Efficiency 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 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 Android-Specific Optimizations 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 Android Technical Architecture Core Components BitchatApplication.kt : Application-level initialization and dependency injection MainActivity.kt : Main activity handling permissions and UI hosting ChatViewModel.kt : MVVM pattern managing app state and business logic BluetoothMeshService.kt : Core BLE mesh networking (central + peripheral roles) EncryptionService.kt : Cryptographic operations using BouncyCastle BinaryProtocol.kt : Binary packet encoding/decoding matching iOS format ChatScreen.kt : Jetpack Compose UI with Material Design 3 Dependencies 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 Binary Protocol Compatibility 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 Publishing to Google Play Preparation Update version information: // In app/build.gradle.kts defaultConfig { versionCode = 2 // Increment for each release versionName = " 1.1.0 " // User-visible version } Create a signed release build: ./gradlew assembleRelease Generate app bundle (recommended for Play Store): ./gradlew bundleRelease Play Store Requirements 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 Distribution Google Play Store : Main distribution channel F-Droid : For open-source distribution Direct APK : For testing and development Cross-Platform Communication 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 Contributing Contributions are welcome! Key areas for enhancement: Performance : Battery optimization and connection reliability UI/UX : Additional Material Design 3 features Security : Enhanced cryptographic features Testing : Unit and integration test coverage Documentation : API documentation and development guides Support & Issues 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 .