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   1  <?php
   2  
   3  declare(strict_types=1);
   4  
   5  /*
   6   * The MIT License (MIT)
   7   *
   8   * Copyright (c) 2014-2020 Spomky-Labs
   9   *
  10   * This software may be modified and distributed under the terms
  11   * of the MIT license.  See the LICENSE file for details.
  12   */
  13  
  14  namespace Jose\Component\Signature\Algorithm;
  15  
  16  use Base64Url\Base64Url;
  17  use function extension_loaded;
  18  use function in_array;
  19  use InvalidArgumentException;
  20  use Jose\Component\Core\JWK;
  21  use RuntimeException;
  22  
  23  final class EdDSA implements SignatureAlgorithm
  24  {
  25      /**
  26       * EdDSA constructor.
  27       *
  28       * @throws RuntimeException if the extension "sodium" is not available
  29       */
  30      public function __construct()
  31      {
  32          if (!extension_loaded('sodium')) {
  33              throw new RuntimeException('The extension "sodium" is not available. Please install it to use this method');
  34          }
  35      }
  36  
  37      public function allowedKeyTypes(): array
  38      {
  39          return ['OKP'];
  40      }
  41  
  42      /**
  43       * @throws InvalidArgumentException if the key is not private
  44       * @throws InvalidArgumentException if the curve is not supported
  45       */
  46      public function sign(JWK $key, string $input): string
  47      {
  48          $this->checkKey($key);
  49          if (!$key->has('d')) {
  50              throw new InvalidArgumentException('The EC key is not private');
  51          }
  52          $x = Base64Url::decode($key->get('x'));
  53          $d = Base64Url::decode($key->get('d'));
  54          $secret = $d.$x;
  55  
  56          switch ($key->get('crv')) {
  57              case 'Ed25519':
  58                  return sodium_crypto_sign_detached($input, $secret);
  59  
  60              default:
  61                  throw new InvalidArgumentException('Unsupported curve');
  62          }
  63      }
  64  
  65      /**
  66       * @throws InvalidArgumentException if the curve is not supported
  67       */
  68      public function verify(JWK $key, string $input, string $signature): bool
  69      {
  70          $this->checkKey($key);
  71  
  72          $public = Base64Url::decode($key->get('x'));
  73  
  74          switch ($key->get('crv')) {
  75              case 'Ed25519':
  76                  return sodium_crypto_sign_verify_detached($signature, $input, $public);
  77  
  78              default:
  79                  throw new InvalidArgumentException('Unsupported curve');
  80          }
  81      }
  82  
  83      public function name(): string
  84      {
  85          return 'EdDSA';
  86      }
  87  
  88      /**
  89       * @throws InvalidArgumentException if the key type is not valid
  90       * @throws InvalidArgumentException if a mandatory key parameter is missing
  91       * @throws InvalidArgumentException if the curve is not suuported
  92       */
  93      private function checkKey(JWK $key): void
  94      {
  95          if (!in_array($key->get('kty'), $this->allowedKeyTypes(), true)) {
  96              throw new InvalidArgumentException('Wrong key type.');
  97          }
  98          foreach (['x', 'crv'] as $k) {
  99              if (!$key->has($k)) {
 100                  throw new InvalidArgumentException(sprintf('The key parameter "%s" is missing.', $k));
 101              }
 102          }
 103          if ('Ed25519' !== $key->get('crv')) {
 104              throw new InvalidArgumentException('Unsupported curve.');
 105          }
 106      }
 107  }