🔐 QryptChat

Quantum-Resistant End-to-End Encrypted Messaging

A secure, privacy-focused chat application built with post-quantum cryptography to protect against both classical and quantum computer attacks.

✨ Features

🛡️ Quantum-Resistant Security

• Post-Quantum Cryptography ready for quantum-safe communication
• End-to-End Encryption with client-side key management
• Perfect Forward Secrecy with automatic key rotation
• Zero-Knowledge Architecture - your data stays private

📱 Progressive Web App

• Cross-Platform: Works on iOS, Android, Desktop, and Web
• Offline Support: Send messages even without internet
• Push Notifications: Never miss a message
• Install Anywhere: Add to home screen on any device

🚀 Real-Time Communication & Sync

• Instant Messaging with WebSocket real-time delivery
• Cross-Device Sync - seamless experience across all devices
• Multi-Session Support - stay logged in on multiple devices
• Typing Indicators to see when others are typing
• Online Presence to know who's available
• Message Status with delivery and read receipts

👥 Social Features

• Phone Verification via Twilio SMS for secure onboarding
• Contact Discovery find friends using phone numbers
• Group Chats up to 100 participants with admin controls
• Media Sharing with end-to-end encrypted file transfers

🌍 Accessibility & Internationalization

• Multi-Language Support - 6 languages (EN, ES, FR, DE, AR, ZH)
• RTL Support for Arabic and other right-to-left languages
• Dark/Light Themes with system preference detection
• Responsive Design optimized for all screen sizes

🏗️ Tech Stack

Layer	Technology	Purpose
Frontend	SvelteKit 5 + Svelte 5	Reactive UI framework
Styling	Vanilla CSS + Custom Properties	Modern design system
Database	Supabase PostgreSQL	User data and messages
Real-time	Supabase Realtime	Live message delivery & sync
Auth	Custom SMS + Supabase	Phone-based verification
SMS	Twilio	SMS verification service
Crypto	Post-Quantum Ready	Future-proof encryption
PWA	Vite PWA Plugin	Offline-first experience
I18n	Custom Store	Multi-language support

🚀 Quick Start

Prerequisites

• Node.js 20+ (recommended)
• pnpm (recommended) or npm
• Supabase account
• Twilio account (for SMS verification)

Installation

# Clone the repository
git clone https://github.com/yourusername/qryptchat.git
cd qryptchat

# Install dependencies
pnpm install

# Set up environment variables
cp .env.example .env
# Edit .env with your Supabase and Twilio credentials

# Run Supabase migrations (if using local Supabase)
pnpx supabase db reset

# Start development server
pnpm dev

The app will be available at http://localhost:8080 (or the PORT specified in your .env file).

Environment Variables

# Development
PORT=8080

# Supabase
PUBLIC_SUPABASE_URL=your_supabase_url
PUBLIC_SUPABASE_ANON_KEY=your_supabase_anon_key
SUPABASE_SERVICE_ROLE_KEY=your_service_role_key

# Twilio (for SMS verification)
TWILIO_ACCOUNT_SID=your_twilio_sid
TWILIO_AUTH_TOKEN=your_twilio_token
TWILIO_PHONE_NUMBER=your_twilio_phone

# App
PUBLIC_APP_URL=http://localhost:8080

🔒 Security Model

QryptChat implements a zero-knowledge architecture where:

• 🔐 All encryption happens client-side before data leaves your device
• 🗝️ Private keys never leave your device and are stored encrypted
• 🔄 Perfect forward secrecy ensures past messages stay secure
• 🛡️ Quantum-resistant algorithms protect against future quantum computers
• 🕵️ Metadata protection minimizes information leakage

📚 Documentation

• 🏗️ Architecture Overview
• 🔒 Encryption Details

🧪 Development

# Start development server
pnpm dev

# Run tests
pnpm test

# Run tests with UI
pnpm test:ui

# Build for production
pnpm build

# Preview production build
pnpm preview

# Lint code
pnpm lint

# Format code
pnpm format

🛣️ Roadmap

✅ Completed (v0.1.0)

• 🏗️ Core Infrastructure - SvelteKit + Vite + PWA setup
• 🎨 Modern UI/UX - Responsive design with dark/light themes
• 🌍 Internationalization - 6 languages with RTL support
• 📱 Progressive Web App - Offline-first with service worker
• 🔐 Authentication System - Phone-based SMS verification
• 🗄️ Database Schema - Complete Supabase setup with RLS
• 🔄 Real-time Foundation - WebSocket infrastructure ready

🚧 In Progress (v0.2.0)

• 💬 Core Messaging - Send/receive messages with encryption
• 🔄 Cross-Device Sync - Real-time synchronization across devices
• 👥 Contact System - Add and manage contacts
• 📊 Presence System - Online/offline status indicators

🎯 Upcoming (v0.3.0+)

• 👥 Group Chats - Multi-user conversations
• 📁 File Sharing - Encrypted media and document sharing
• 🔍 Message Search - Full-text search across conversations
• 🔔 Push Notifications - Cross-platform notification system
• 🎥 Voice & Video - End-to-end encrypted calls
• 🔐 Advanced Encryption - Post-quantum cryptography implementation

🔮 Future Vision

• 🤖 AI Integration - Smart message suggestions and translation
• 🌐 Federation - Connect with other secure messaging platforms
• 📈 Analytics - Privacy-preserving usage insights
• 🎨 Customization - Custom themes and chat backgrounds

📄 License

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

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Built with ❤️ for a quantum-safe future