🌐 Cross-Chain Identity Hub

Link Your Decentralized Identity Across All Networks

The Cross-Chain Identity Hub is a foundational infrastructure project that links multiple blockchain addresses (Ethereum, Solana, Bitcoin, etc.) to a single, verifiable identity. This enables true cross-chain ownership verification and identity resolution for seamless multi-chain interactions.

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📁 Project Structure

cross-chain-identity-hub/
├── backend/           # Node.js API server for verification
├── contracts/         # Solidity smart contracts
└── frontend/          # React user interface

Architecture Overview:

• Backend: Challenge generation, proof verification, ENS resolution
• Contracts: On-chain storage and verification logic
• Frontend: User interface for identity linking and management

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🛠️ Technology Stack

Component	Technologies	Purpose
Frontend	React, TypeScript, Tailwind CSS, Lucide Icons	User interface and interactions
Backend	Node.js, Express, Ethers.js, Crypto libraries	API endpoints and verification logic
Smart Contracts	Solidity, Foundry	On-chain storage and proof verification
Wallet Integration	Ethers.js, Solana Web3.js	Multi-chain wallet connectivity

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🚀 Quick Start

Prerequisites

• Node.js v18+
• Git
• Foundry (for smart contracts)

1. Clone Repository

git clone https://github.com/your-org/cross-chain-identity-hub.git
cd cross-chain-identity-hub

2. Backend Setup

cd backend
npm install
./start.sh

The API server will start on http://localhost:3000

Test the API:

# Health check
curl http://localhost:3000/health

# Run example test
node examples/api-test.js

3. Smart Contracts

cd contracts
forge install
forge build
forge test

Deploy to testnet:

forge script script/Deploy.s.sol --rpc-url sepolia --broadcast --verify

4. Frontend

cd frontend
npm install
npm run dev

Access the application at http://localhost:3000

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📡 API Reference

Endpoint	Method	Description	Example
/health	GET	Health check	curl http://localhost:3000/health
/challenge	POST	Generate identity challenge	See below
/verify	POST	Verify proof submission	See examples/

Generate Challenge Example:

curl -X POST http://localhost:3000/challenge \
  -H "Content-Type: application/json" \
  -d '{
    "ensName": "alice.eth",
    "chain": "bitcoin", 
    "address": "1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa"
  }'

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🔧 Development Commands

Smart Contracts (Foundry)

# Build contracts
forge build

# Run tests
forge test

# Generate gas report
forge test --gas-report

# Coverage analysis
forge coverage

# Clean artifacts
forge clean

Backend

# Start development server
npm run dev

# Run tests
npm test

# Generate API documentation
npm run docs

Frontend

# Development server
npm run dev

# Build for production
npm run build

# Run tests
npm test

# Type checking
npm run type-check

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🔍 Example: Identity Resolution

A successfully linked identity in the Cross-Chain Identity Hub:

ENS Name: vitalik.eth
Blockchain: Ethereum (Ξ)

Details:
  Resolved Address: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045
  Proof Hash: 0xe8532100...afddd408
  Verification Method: ENS Registry
  Verified On: Sep 28, 2025, 12:20 AM
  Status: ✅ Verified

Multi-Chain Linking:

• Ethereum: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045
• Solana: DRiP2Pn2K6fuMLKQmt5rZWyHiUZ6ygcT4s3FzMyK3qK
• Bitcoin: bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh

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🧪 Testing

Unit Tests

# Backend tests
cd backend && npm test

# Contract tests
cd contracts && forge test

# Frontend tests  
cd frontend && npm test