bitchat-tui

bitchat-tui

bitchat-tui is a terminal user interface client for BitChat, a secure peer-to-peer messaging protocol that operates over Bluetooth Low Energy. It enables off-grid encrypted communication without requiring internet connectivity or central servers. The application automatically scans for nearby peers via Bluetooth LE and establishes direct mesh connections.
All messages are end-to-end encrypted using X25519 Elliptic Curve Diffie-Hellman for key exchange, AES-256-GCM for message encryption with integrity authentication, and Ed25519 digital signatures for verifying message authenticity. Channel passwords are derived using PBKDF2-SHA256 with 100,000 rounds. Large messages are automatically fragmented and reassembled across Bluetooth LE's limited packet size.
The TUI provides a sidebar-based interface built with ratatui and crossterm, organizing conversations into public chat, named channels, direct messages, and a blocked users list. Unread message indicators and section counters help track activity across channels.
Written in Rust, bitchat-tui runs on Linux, macOS, and Windows.

State is persisted in ~/.bitchat/state.json and includes:
Identity -- Ed25519 signing key and X25519 encryption key, generated on first launch
Nickname -- User-chosen display name
Channels -- Joined channels, ownership info, and encrypted channel passwords
Blocked peers -- SHA256 fingerprints of blocked users
Channel passwords are encrypted at rest using AES-256-GCM with keys derived from the identity key.

The application accepts no command-line flags or options; all configuration is done interactively through TUI commands after launch. Requires a Bluetooth LE capable adapter. On Linux, the dbus system is required for Bluetooth access. Building from source on Windows requires Microsoft Visual C++ Build Tools with the "Desktop development with C++" workload. Communication range is limited by Bluetooth LE signal reach, typically around 10-100 meters depending on hardware.

bluetuith(1), bluetoothctl(1), hcitool(1)