Linda

Problem Statement

Linda combines an intuitive mobile app with proof of humanity authentication and private real-time location streaming into one social network. The goal of Linda is to connect friends and family all across the world without corporate surveillance. Unlike traditional social platforms optimized for engagement and ad revenue, Linda is a mobile first app that fosters genuine friendships through spontaneous meetups when friends are nearby or traveling.Every account requires Self Protocol's proof-of-humanity verification using passport-based zero-knowledge proofs—eliminating bots, spam, and fake profiles at the protocol level. Location data processes inside Oasis Sapphire's Trusted Execution Environments (TEEs), so even we can't access your coordinates. You control per-friend privacy: share city-level location or real-time GPS.

Solution

Three-Layer Architecture: Frontend → Self Protocol (Celo): React Native app build with expo generates a UUID and deep-links to Self mobile app using @selfxyz/qrcode SDK. Users scan their passport, Self creates a zero-knowledge proof and posts it to our ProofOfHuman Solidity contract on Celo Sepolia. The contract verifies humanity and returns an action nullifier—a privacy-preserving user ID. No passport data touches our app.Frontend → ROFL Backend (Oasis TEE): Location data streams via HTTPS directly to our Node.js ROFL container running in Intel TDX enclaves. This avoids constant blockchain transactions (bad UX, high gas). Users send GPS coordinates; TEE calculates proximity using Haversine formula.TEE → Sapphire Storage: TEE encrypts and stores location data in Oasis Sapphire confidential smart contracts. Hardware-level encryption ensures even node operators can't read coordinates. When friends are nearby, TEE writes minimal notification events to blockchain—frontend displays alerts without accessing raw locations.