Bitchat Rust

A performant Rust implementation of the Bitchat protocol with WebAssembly support for browsers.

Overview

Decentralized, peer-to-peer messaging protocol designed for secure, private, and censorship-resistant communication over ephemeral mesh networks.

Core Features:

• End-to-end encryption using Noise Protocol Framework (XX pattern)
• BLE mesh networking with Nostr relay fallback
• Location-based channels using geohash precision levels
• Message fragmentation, compression, and deduplication
• Binary wire protocol with full canonical compatibility

Advanced Features (opt-in via --features experimental):

• File transfer with chunked uploads and SHA-256 integrity verification
• Group messaging with role-based permissions
• Multi-device session synchronization
• Capability negotiation with graceful degradation

Architecture

CSP-based multi-task orchestrator with channel communication

• bitchat-core - Protocol, cryptography, and data structures
• bitchat-runtime - Task orchestration and lifecycle management
• bitchat-ble / bitchat-nostr - Transport implementations
• bitchat-cli / bitchat-web - Application frontends

Cryptography: Noise_XX_25519_ChaChaPoly_SHA256
Identity: Ed25519 signatures, Curve25519 keys
Sync: GCS filter-based gossip with Bloom deduplication

See docs/protocol-architecture.md for complete specification.

Building

Native

nix develop              # Enter development environment (optional)
just build               # Build all crates
just test                # Run tests
just demo                # Run CLI demo (BLE + Nostr)

With Experimental Features

cargo build --features experimental
cargo test --features experimental

WebAssembly

just build-wasm          # Build WASM module for web
just serve-web           # Serve demo at http://localhost:8000

Testing

The project includes comprehensive integration testing:

• Canonical compatibility tests verify wire format compatibility
• Property-based tests for message store integrity
• Integration tests for transport and runtime behavior
• Simulator for cross-implementation testing (see simulator/)

Reference

• bitchat - iOS/macOS (main implementation)
• bitchat-android - Android (production)
• deepwiki - generative docs

License

Licensed under Apache 2.0, see LICENSE.