hmac-authentication npm

Signs and authenticates HTTP requests based on a shared-secret HMAC signature.

Developed in parallel with the following packages for other languages:

• Go: github.com/18F/hmacauth
• Ruby: hmac_authentication

Installation

$ npm install hmac-authentication --save

Authenticating incoming requests

Assuming you're using Express, during initialization of your application, where config.signatureHeader identifies the header containing the message signature, config.headers is a list of headers factored into the signature, and config.secretKey is the shared secret between your application and the service making the request:

var express = require('express');
var bodyParser = require('bodyParser');
var HmacAuth = require('hmac-authentication');
var config = require('./config.json');

function doLaunch(config) {
  var middlewareOptions = {
    verify: HmacAuth.middlewareAuthenticator(
      config.secretKey, config.signatureHeader, config.headers)
  };
  var server = express();
  server.use(bodyParser.raw(middlewareOptions));

  // Continue server initialization...
}

If you're not using Express, you can use something similar to the following:

var HmacAuth = require('hmac-authentication');
var config = require('./config.json');

// When only used for authentication, it doesn't matter what the first
// argument is, because the hash algorithm used for authentication will be
// parsed from the incoming request signature header.
var auth = new HmacAuth(
  'sha1', config.secretKey, config.signatureHeader, config.headers);

// rawBody must be a string.
function requestHandler(req, rawBody) {
  var authenticationResult = auth.authenticateRequest(req, rawBody);

  if (authenticationResult[0] != HmacAuth.MATCH) {
    // Handle authentication failure...
  }
}

Signing outgoing requests

Do something similar to the following. rawBody must be a string.

var HmacAuth = require('hmac-authentication');
var config = require('./config.json');

var auth = new HmacAuth(
  config.digestName, config.secretKey, config.signatureHeader, config.headers);

function makeRequest(req, rawBody) {
  // Prepare request...
  auth.signRequest(req, rawBody);
}

Public domain

This project is in the worldwide public domain. As stated in CONTRIBUTING:

This project is in the public domain within the United States, and copyright and related rights in the work worldwide are waived through the CC0 1.0 Universal public domain dedication.

All contributions to this project will be released under the CC0 dedication. By submitting a pull request, you are agreeing to comply with this waiver of copyright interest.