A privacy-focused real-time location tracking app that connects friends worldwide.

Linda enables friends to share their locations in real-time while maintaining complete control over their privacy. Built for ETHGlobal Buenos Aires, the app demonstrates how trusted execution environments (TEEs) and blockchain technology can create a secure, privacy-preserving location sharing experience.

• Privacy-First Design: Users control their location sharing granularity (exact coordinates vs. city-level)
• Real-Time Updates: WebSocket-powered live location broadcasting to friends
• Confidential Computation: Backend runs inside Oasis ROFL TEE for tamper-proof execution
• Privacy-Preserving Identity: Self Protocol integration for anonymous age and country verification
• Cross-Platform: React Native app works on iOS, Android, and web

• Frontend: React Native with Expo
• Backend: Oasis ROFL (Runtime Off-chain Logic) with TypeScript, Express, and WebSocket
• Smart Contracts: Solidity on Celo (Sepolia testnet and Mainnet)
• Identity: Self Protocol for zero-knowledge identity verification
• Database: SQLite encrypted within TEE

Mobile App (React Native)
    ↓ HTTPS/WSS
Backend API (Express + WebSocket in ROFL TEE)
    ↓ SQLite (encrypted in TEE)
Privacy-controlled location sharing
    ↓ WebSocket broadcast
Real-time updates to friends

linda/
├── frontend/          # React Native (Expo) mobile app
├── oasis/             # ROFL backend (TypeScript + Express + WebSocket)
├── contracts/         # Solidity contracts (Foundry)
├── CLAUDE.md          # Development guide
├── CONNECT.md         # Frontend-backend integration guide
└── TESTING.md         # Testing procedures

cd frontend
npm install
npm start

cd oasis
npm install
docker compose up --build

cd contracts
npm install
forge build

For detailed setup instructions, see CLAUDE.md.

• Friend-Only Sharing: Location data only shared with bidirectional friends
• Granular Privacy: Choose between exact GPS coordinates or city-level sharing
• No History: Only current location stored, no tracking history
• TEE Enforcement: Privacy rules enforced inside trusted execution environment
• Verifiable Security: Remote attestation ensures code integrity

• Celo Sepolia: 0x16ECBA51e18a4a7e61fdC417f0d47AFEeDfbed74
• Celo Mainnet: 0xe57F4773bd9c9d8b6Cd70431117d353298B9f5BF

• CLAUDE.md - Comprehensive development guide
• CONNECT.md - Frontend-backend integration
• TESTING.md - Testing procedures

• Oasis ROFL - Confidential off-chain computation
• Self Protocol - Privacy-preserving identity
• Expo - React Native framework
• Celo - Mobile-first blockchain

Built for ETHGlobal Buenos Aires 2024