Krypt 🔐

Privacy-first, zero-knowledge End-to-End Encrypted messenger.

Architecture

• Android Client — Jetpack Compose, Room DB, OkHttp WebSockets, WebRTC, CameraX
• Python Backend — FastAPI WebSocket relay (never sees plaintext)

Cryptography

• Identity: UUID + 2048-bit RSA Key Pair (generated on device, never leaves device)
• Messages: AES-256-GCM per message, AES key encrypted with recipient's RSA public key
• Files: Chunked (64KB), each chunk AES-256-GCM encrypted independently

Setup

1. Deploy Backend

cd server
pip install -r requirements.txt
python main.py
# Or: docker build -t krypt-server . && docker run -p 8000:8000 krypt-server

2. Configure Android App

Edit NetworkClient.kt and set your server URL:

const val SERVER_URL = "ws://YOUR_SERVER_IP:8000/ws"

3. Build APK

Push to GitHub → Actions tab → Download krypt-debug-apk artifact.

Features

• ✅ No accounts / No logins — UUID-based identity
• ✅ Zero-knowledge server — server routes ciphertext only
• ✅ E2EE text messaging
• ✅ E2EE file & photo sharing (chunked)
• ✅ WebRTC P2P audio/video calls
• ✅ 24-hour expiring encrypted statuses
• ✅ CameraX in-app camera
• ✅ Ultra-minimalist dark UI