An implementation of the HTTP HMAC Spec in PHP that integrates with popular libraries such as Symfony and Guzzle.


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This library implements version 2.0 of the HTTP HMAC Spec to sign and verify RESTful Web API requests. It integrates with popular frameworks and libraries, like Symfony and Guzzle, and can be used on both the server and client.


Use Composer and add it as a dependency to your project's composer.json file:

    "require": {
        "acquia/http-hmac-php": "~3.3.0"

Please refer to Composer's documentation for more detailed installation and usage instructions.


Sign an API request sent via Guzzle

use Acquia\Hmac\Guzzle\HmacAuthMiddleware;
use Acquia\Hmac\Key;
use GuzzleHttp\Client;
use GuzzleHttp\HandlerStack;

// Optionally, you can provide signed headers to generate the digest. The header keys need to be provided to the middleware below.
$options = [
  'headers' => [
    'X-Custom-1' => 'value1',
    'X-Custom-2' => 'value2',

// A key consists of your UUID and a MIME base64 encoded shared secret.
$key = new Key('e7fe97fa-a0c8-4a42-ab8e-2c26d52df059', base64_encode('secret'));

// Provide your key, realm and optional signed headers.
$middleware = new HmacAuthMiddleware($key, 'CIStore', array_keys($options['headers']));

// Register the middleware.
$stack = HandlerStack::create();

// Create a client.
$client = new Client([
    'handler' => $stack,

// Request.
$result = $client->get('', $options);

Authenticate the request using PSR-7-compatible requests

use Acquia\Hmac\RequestAuthenticator;
use Acquia\Hmac\ResponseSigner;

// $keyLoader implements \Acquia\Hmac\KeyLoaderInterface
$authenticator = new RequestAuthenticator($keyLoader);

// $request implements PSR-7's \Psr\Http\Message\RequestInterface
// An exception will be thrown if it cannot authenticate.
$key = $authenticator->authenticate($request);

$signer = new ResponseSigner($key, $request)
$signedResponse = $signer->signResponse($response);

Authenticate using Silex's SecurityServiceProvider

In order to use the provided Silex security provider, you will need to include the following optional libraries in your project's composer.json:

    "require": {
        "symfony/psr-http-message-bridge": "~0.1",
        "symfony/security": "~3.0",
        "zendframework/zend-diactoros": "~1.3.5"

Sample implementation:

use Acquia\Hmac\HmacSecurityProvider;
use Silex\Application;
use Silex\Provider\SecurityServiceProvider;

$app = new Application();

// $keyLoader implements \Acquia\Hmac\KeyLoaderInterface
$app->register(new SecurityServiceProvider());
$app->register(new HmacSecurityProvider($keyLoader));

$app['security.firewalls'] = [
    'hmac-auth' => array(
        'pattern' => '^/api/',
        'hmac' => true,


Authenticate using Symfony's Security component

In order to use the provided Symfony integration, you will need to include the following optional libraries in your project's composer.json

    "require": {
        "symfony/psr-http-message-bridge": "~0.1",
        "symfony/security": "~3.0",
        "zendframework/zend-diactoros": "~1.3.5"

Sammple implementation:

# app/config/parameters.yml
   hmac_keys: {"key": "secret"}

# app/config/services.yml
        class: Acquia\Hmac\KeyLoader
            $keys: '%hmac_keys%'

        class: Acquia\Hmac\RequestAuthenticator
         - '@hmac.keyloader'
        public: false

        class: Acquia\Hmac\Symfony\HmacAuthenticationEntryPoint
        class: Acquia\Hmac\Symfony\HmacAuthenticationProvider
            - '@hmac.request.authenticator'
        public: false
        class: Acquia\Hmac\Symfony\HmacAuthenticationListener
        arguments: ['@security.token_storage', '@security.authentication.manager', '@hmac.entry-point']
        public: false

# app/config/security.yml
    # ...

            pattern:   ^/api/
            stateless: true
            wsse:      true
// src/AppBundle/AppBundle.php
namespace AppBundle;

use Acquia\Hmac\Symfony\HmacFactory;
use Symfony\Component\HttpKernel\Bundle\Bundle;
use Symfony\Component\DependencyInjection\ContainerBuilder;

class AppBundle extends Bundle
    public function build(ContainerBuilder $container)
        $extension = $container->getExtension('security');
        $extension->addSecurityListenerFactory(new HmacFactory());

Contributing and Development

Submit changes using GitHub's standard pull request workflow.

All code should adhere to the following standards:

Use PHP_CodeSniffer to validate coding style and automatically fix problems according to the PSR-2 standard:

$ vendor/bin/phpcs --standard=PSR2 --runtime-set ignore_warnings_on_exit true --colors src/.
$ vendor/bin/phpcs --standard=PSR2 --runtime-set ignore_warnings_on_exit true --colors test/.
$ vendor/bin/phpcbf --standard=PSR2 src/.
$ vendor/bin/phpcbf --standard=PSR2 test/.

Refer to PHP Project Starter's documentation for the Apache Ant targets supported by this project.