ETH Authenticator package for Node

This package works as a middleware for an Express app.

Exmaple

Refer this repository for an example setup, including a working demo server: https://github.com/pelieth/node-eth-auth-server.

Setup

npm install node-eth-auth

Usage

Insert it as a middleware to authenticating routes in your Express app. After this middleware, the context object is stored as req.ethAuth, which has attributes listed inside callback functions.

const express = require('express');
const EthAuth = require('node-eth-auth');

let ethAuthMiddleware = new EthAuth({
  // all options and their default values
  signature: 'Signature',
  message: 'Message',
  address: 'Address',
  banner: 'eth-auth',
});

const app = express();

/* --- Step 1: authentication request --- */
app.get('/auth/:Address', ethAuthMiddleware, (req, res) => { 
  //           ^^^^^^^^ the URL parameter

  /* req.ethAuth
   *   message: The challenge string.
   */
});

/* --- Step 2: challenge response --- */
app.get('/auth/:Message/:Signature', ethAuthMiddleware, (req, res) => { 
  /*
   * req.ethAuth
   *   recoveredAddress: The recovered wallet address for the signature.
   */
});

Workflow

1. The client emits an authentication request.
2. The server stores and responds with a challenge string.
3. The client prompts and signs a message (challenge, banner) for a user, and send the challenge response to the server.
4. The server looks up that challenge string, and matches the corresponding address against the one recovered from the signature. Respond the client with the result.
5. The authentication is now done.

Options

• signature='Signature'

• message='Message'

• address='Address'
  These options specify the corresponding URL parameter (in URL, not in query string!) for a request.

• banner='eth-auth':String
  An identifier for your app that is sent to the user when an authentication request is made. The user signs the challenge string along with the banner to prevent spoofings. It is strongly discouraged to use the default value.

Testing

npm install
npm test