Ethereum Guide

Ethereum Wallet Authentication

Authenticate using Ethereum wallet signatures. EIP-191 challenge-response, wallet registration, and cryptographic identity for agents and dApps.

Wallet-Based Identity

Every Ethereum wallet has a unique address and private key. GitHat uses this for authentication: the address is the identity, the signature is the credential. Cryptographically secure by design.

EIP-191 Signing

Challenge-response with EIP-191: the nonce prevents replay attacks, the signature proves wallet ownership, and the recovered address must match the registered wallet. Standard Ethereum security.

Token Security

Two-minute tokens are deliberate. AI agents operate in rapid cycles. Short tokens mean a compromised token expires before it can be misused. Re-authentication is cheap (one signature).

Install

npm install ethers

Example

// Wallet authentication with ethers.js v6
import { ethers } from 'ethers';

const wallet = new ethers.Wallet(process.env.PRIVATE_KEY);

// Register (one-time)
await fetch('https://api.githat.io/agent/register', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json', Authorization: 'Bearer USER_TOKEN' },
  body: JSON.stringify({ walletAddress: wallet.address, chainId: 1, name: 'My Agent' })
});

// Authenticate (every 2 minutes)
const { nonce } = await fetch('https://api.githat.io/agent/challenge', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ wallet: wallet.address })
}).then(r => r.json());

const signature = await wallet.signMessage(nonce);
const { access_token } = await fetch('https://api.githat.io/agent/token', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ wallet: wallet.address, signature, nonce })
}).then(r => r.json());
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