Mostro Chat

mostro-chat is a minimalist peer-to-peer chat application written in Rust, utilizing the Nostr protocol for decentralized and secure communication. It integrates the nostr-sdk for event handling and encryption, and features a terminal-based user interface (TUI) built with ratatui and crossterm.

Features

• Peer-to-Peer Messaging: Direct communication between users without centralized servers.
• End-to-End Encryption: Messages are encrypted using a shared key derived from ECDH (Elliptic Curve Diffie-Hellman).
• Simplified NIP-59: Implements a non-standard version of NIP-59 for event wrapping and encryption.
• Proof of Work: Applies a configurable proof-of-work requirement to outgoing messages to deter spam.
• Time-Based Filtering: Displays messages from the last N seconds (default: 600 seconds).

Prerequisites

• Rust: Install Rust from rust-lang.org if you haven’t already.
• Nostr Relay: The app connects to wss://relay.mostro.network. Ensure access to this relay or use another relay.

Installation

Clone the repository:

    git clone https://github.com/MostroP2P/mostro-chat.git
    cd mostro-chat

Run the program:

    cargo run -- -s <sender_secret> -p <receiver_pubkey>

Usage

The application requires two arguments:

    -s, --sender-secret <SENDER_SECRET>: Your private key (in hex or bech32 format, e.g., nsec1...).
    -p, --receiver-pubkey <RECEIVER_PUBKEY>: The recipient’s public key (in hex or bech32 format, e.g., npub1...).

Example:

cargo run --release -- -s nsec1yourprivatekeyhere -p npub1recipientpubkeyhere

Controls

• Input Field: Type your message in the bottom section of the TUI.
• Send Message: Press Enter to send the typed message.
• Exit: Press Esc to quit the application.

Message Display

• Messages appear in the main area.
• Only messages from the last 10 minutes (600 seconds) are shown by default.
• Sent messages are prefixed with "You: ".
• Received messages are prefixed with "Counterpart: ".

Configuration

The following constants in the code can be modified:

• N_SECONDS: Time window for displaying messages (default: 600 seconds). Edit this in main.rs.
• POW_DIFFICULTY: Proof-of-work difficulty for outgoing messages (default: 2). Adjust in main.rs.
• RELAY_URL: Nostr relay URL (default: wss://relay.mostro.network). Change in main.rs.

How It Works

Shared Key Generation: Uses ECDH with the sender’s private key and receiver’s public key to create a shared key.

Message Encryption: Messages are wrapped in a simplified NIP-59 event, encrypted with the shared key, and signed with an ephemeral key.

Event Subscription: Subscribes to events targeting the shared key’s public key via the Nostr relay.

Real-Time Updates: Decrypts and displays incoming messages in the TUI if they fall within the time window.

Technical Details

NIP-59 Simplification: The app uses a custom, non-standard NIP-59 implementation for gift-wrapped events.

Asynchronous Handling: Employs tokio for managing Nostr client tasks and TUI updates concurrently.

You can find more information about here

License

This project is licensed under the MIT License. See the LICENSE file for details.

Contributing

Contributions are encouraged! Feel free to open issues or submit pull requests on GitHub.