Identity Relayer

Express.js application that relays identity proofs to the Ethereum blockchain.

Features

• Single endpoint to accept ETH addresses and ZK proofs
• Input validation for hex strings and ETH addresses
• Ethers.js integration for blockchain interaction
• Error handling and logging
• Health check endpoint

Installation

npm install

Configuration

Create a .env file with the following variables:

# Server Configuration
PORT=3000

# Ethereum Configuration
RPC_URL=https://mainnet.infura.io/v3/YOUR_INFURA_PROJECT_ID
# Or use a local node: http://localhost:8545

# Contract Configuration (to be filled once provided)
CONTRACT_ADDRESS=your_contract_address
CONTRACT_ABI=your_contract_abi_json

# Private key for signing transactions (keep secure!)
PRIVATE_KEY=your_private_key

Usage

Start the server

# Development mode
npm run dev

# Production mode
npm start

API Endpoints

Submit Proof (with ZK verification)

• URL: POST /submit-proof
• Body:

  {
    "ethAddress": "0x742d35Cc6635C0532925a3b8D098D0ba37b5",
    "zkProof": "0x1234abcd..."
  }

• Response:

  {
    "success": true,
    "message": "Proof submitted and address whitelisted successfully",
    "transactionHash": "0x...",
    "gasUsed": 21000,
    "blockNumber": 12345,
    "status": true
  }

Simple Whitelist (without ZK verification)

• URL: POST /whitelist
• Body:

  {
    "ethAddress": "0x742d35Cc6635C0532925a3b8D098D0ba37b5"
  }

• Response:

  {
    "success": true,
    "message": "Address whitelisted successfully",
    "transactionHash": "0x...",
    "gasUsed": 21000,
    "blockNumber": 12345,
    "status": true
  }

Health Check

• URL: GET /health
• Response:

  {
    "status": "healthy",
    "timestamp": "2023-12-07T10:30:00.000Z",
    "web3Connected": true
  }

Contract Integration

Once you provide the contract ABI and address, update the submitToContract function in server.js to implement the actual blockchain interaction.

Error Handling

The API validates:

• Required fields (ethAddress, zkProof)
• ETH address format (40 hex characters)
• ZK proof format (hex string starting with 0x)

Common error responses:

• 400: Bad request (validation errors)
• 500: Internal server error