Secure End-to-End Encrypted Messaging & File-Sharing System

A fully functional, secure messaging application featuring End-to-End Encryption (E2EE), Secure File Sharing, and a modern Warm Tactile UI.

Key Features

🔒 Security & Cryptography

• End-to-End Encryption: Messages are encrypted on the client using AES-GCM (256-bit) before transmission. The server never sees the plaintext.
• Key Exchange: Secure ECDH (Elliptic Curve Diffie-Hellman) key exchange using the Web Crypto API (P-256 curve).
• Identity Verification: ECDSA signatures ensure that public keys cannot be spoofed (MITM protection).
• Forward Secrecy: Unique session keys are generated for each conversation.
• Secure File Sharing: Files are encrypted in the browser, uploaded as encrypted blobs, and decrypted only by the intended recipient.

🎨 UI/UX

• Warm Tactile Design: A custom "Unified Card" interface using a warm paper palette (#E1CCA7 base) and crisp white cards.
• Unified Layout: Seamless sidebar and chat integration for a professional desktop-app feel.
• Physics-Based Animations: Smooth transitions powered by framer-motion.
• Responsive: Fully responsive layout that adapts to mobile devices.

🛡️ Auditing & Compliance

• Audit Logging: Comprehensive server-side logging of security events (login attempts, key exchanges, replay attacks).
• Threat Modeling: Full STRIDE analysis implemented and documented.

Project Structure

.
├── client/          # React frontend (Vite + Framer Motion)
│   ├── src/
│   │   ├── components/ # UI Components (AppShell, ChatPanel, Sidebar)
│   │   ├── crypto/     # Cryptographic modules (Web Crypto API)
│   │   ├── styles/     # CSS Design System (Warm Tactile)
│   │   └── pages/      # Application Pages
│   └── ...
│
└── server/          # Node.js + Express backend
    ├── models/      # MongoDB Schemas (User, Message, File, AuditLog)
    ├── routes/      # Secure API Endpoints
    └── ...

Setup Instructions

Prerequisites

• Node.js (v18+)
• MongoDB (Local or Atlas)

1. Backend Setup

cd server
npm install

Create a .env file:

MONGODB_URI=mongodb://localhost:27017/secure-messaging
PORT=5000
JWT_SECRET=your-secure-secret

Start the server:

npm start

2. Frontend Setup

cd client
npm install
npm run dev

Access the app at http://localhost:5173.

Implementation Status

✅ Completed Features

• User Authentication (JWT + bcrypt)
• ECDH Key Exchange (P-256)
• AES-GCM Message Encryption
• Encrypted File Sharing
• MITM Protection (ECDSA Signatures)
• Audit Logging
• UI Polish (Warm Tactile Unified Card)

🚀 Future Roadmap

• Group Chat E2EE (Sender Keys)
• Voice/Video Calls (WebRTC)
• Push Notifications

Security Architecture

For a deep dive into the security architecture, threat model, and cryptographic protocols, please refer to the Project Report and STRIDE Analysis.