🔐 HushNet Backend

HushNet Backend is a secure backend server for an end-to-end encrypted (E2EE) instant messaging application, built with Rust and Axum. It implements the Signal Protocol (X3DH + Double Ratchet) to provide cryptographically secure communication between users and devices.

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📋 Table of Contents

• 🔐 HushNet Backend
  • 📋 Table of Contents
  • ✨ Features
  • 🚀 Quick Start
  • 📚 Documentation
    • Core Documentation
    • Setup & Deployment
    • Additional Resources
  • 🏗️ Architecture
    • Communication Flow
  • 🛠️ Technology Stack
    • Core Framework
    • Cryptography
    • Database
    • Utilities
  • 📋 Prerequisites
  • ⚙️ Installation
    • Quick Install
  • 🔧 Configuration
    • Environment Variables
  • 🤝 Contributing
    • Quick Start for Contributors
  • 📄 License
  • 🙏 Acknowledgments
  • 📞 Contact

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✨ Features

• 🔒 End-to-End Encryption (E2EE): Signal Protocol implementation (X3DH + Double Ratchet)
• 🔐 Ed25519 Authentication: Cryptographic signature-based authentication (no JWT)
• 👥 Multi-Device Support: Full support for multiple devices per user
• 💬 Instant Messaging: Direct messages and group chats
• 🔑 Cryptographic Key Management: Identity keys, prekeys, signed prekeys, one-time prekeys
• ⚡ Real-time Communication: WebSockets for instant notifications
• 📡 PostgreSQL LISTEN/NOTIFY: Real-time event notifications
• 🚀 High Performance: Asynchronous backend powered by Tokio
• 🐳 Docker Ready: Docker configuration for PostgreSQL
• 🛡️ Anti-Replay Protection: Timestamp-based request validation

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🚀 Quick Start

# Clone the repository
git clone https://github.com/HushNet/HushNet-Backend.git
cd HushNet-Backend

# Start PostgreSQL with Docker
docker build -t hushnet-postgres .
docker run -d -p 5432:5432 --name hushnet-db hushnet-postgres

# Configure environment
echo "DATABASE_URL=postgres://postgres:dev@localhost:5432/e2ee" > .env

# Build and run
cargo build --release
cargo run

Server will start at http://127.0.0.1:8080 🎉

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📚 Documentation

Comprehensive documentation is organized into the following sections:

Core Documentation

• API Reference - Complete API endpoint documentation
• Database Schema - Database structure and relationships
• Security & Cryptography - Encryption protocols and authentication
• WebSocket & Real-time - WebSocket implementation and events
• Project Structure - Code organization and architecture

Setup & Deployment

• Installation Guide - Detailed setup instructions
• Configuration Guide - Environment variables and settings
• Docker Deployment - Docker and Docker Compose setup
• Development Guide - Development workflow and tools

Additional Resources

• Contributing Guidelines - How to contribute to the project
• Changelog - Version history and updates
• Roadmap - Future features and improvements

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🏗️ Architecture

HushNet Backend follows a clean, modular architecture:

┌─────────────────────────────────────────────────────────┐
│                    Client Applications                   │
└───────────────────────┬─────────────────────────────────┘
                        │ HTTP/WebSocket
┌───────────────────────▼─────────────────────────────────┐
│                   Axum Web Framework                     │
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────┐    │
│  │   Routes    │  │ Middlewares │  │ Controllers │    │
│  └──────┬──────┘  └──────┬──────┘  └──────┬──────┘    │
│         │                 │                 │            │
│         └────────┬────────┴────────┬────────┘           │
│                  │                 │                     │
│         ┌────────▼─────────┐  ┌───▼─────────┐          │
│         │    Services      │  │ Repositories │          │
│         └──────────────────┘  └───────┬──────┘          │
└───────────────────────────────────────┼─────────────────┘
                                        │
                    ┌───────────────────▼──────────────────┐
                    │       PostgreSQL Database            │
                    │  (LISTEN/NOTIFY for real-time)       │
                    └──────────────────────────────────────┘

Communication Flow

1. Authentication: Ed25519 signature verification on each request
2. Key Exchange: X3DH handshake to establish secure sessions
3. Messaging: Double Ratchet encryption for each message
4. Real-time: PostgreSQL NOTIFY → WebSocket → Clients

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🛠️ Technology Stack

Core Framework

• Rust (Edition 2021) - Programming language
• Axum 0.7 - Async web framework
• Tokio - Async runtime
• SQLx 0.8 - PostgreSQL async client

Cryptography

• ed25519-dalek 2.0 - Digital signatures
• base64 - Base64 encoding/decoding

Database

• PostgreSQL 14+ - Relational database
• LISTEN/NOTIFY - Real-time notification mechanism

Utilities

• Serde - JSON serialization/deserialization
• Tracing - Structured logging
• Dotenvy - Environment variable management
• Anyhow - Error handling
• UUID - Unique identifier generation
• Chrono - Date and time handling

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📋 Prerequisites

• Rust 1.70+ (Install)
• PostgreSQL 14+ (Install)
• Docker (optional, for database)
• Cargo (included with Rust)

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⚙️ Installation

For detailed installation instructions, see the Installation Guide.

Quick Install

# 1. Clone repository
git clone https://github.com/HushNet/HushNet-Backend.git
cd HushNet-Backend

# 2. Install dependencies
cargo build

# 3. Setup database (with Docker)
docker build -t hushnet-postgres .
docker run -d -p 5432:5432 --name hushnet-db hushnet-postgres

# 4. Configure environment
cp .env.example .env
# Edit .env with your configuration

# 5. Run server
cargo run

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🔧 Configuration

Environment Variables

Create a .env file in the project root:

# Database
DATABASE_URL=postgres://postgres:dev@localhost:5432/e2ee

# Logging
RUST_LOG=info

For complete configuration options, see the Configuration Guide.

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🤝 Contributing

We welcome contributions! Please see our Contributing Guidelines for details.

Quick Start for Contributors

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Make your changes
4. Run tests (cargo test)
5. Format code (cargo fmt)
6. Check lints (cargo clippy)
7. Commit changes (git commit -m 'Add amazing feature')
8. Push to branch (git push origin feature/amazing-feature)
9. Open a Pull Request

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📄 License

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

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🙏 Acknowledgments

• Signal Protocol for cryptographic inspiration
• Axum for the excellent web framework
• The Rust community 🦀

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📞 Contact

• GitHub Issues: Open an issue
• GitHub Discussions: Join the discussion

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Built with ❤️ and 🦀 Rust

⭐ If you like this project, please give it a star!

Documentation • API Reference • Contributing