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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\Core;
  15  
  16  use function array_key_exists;
  17  use Base64Url\Base64Url;
  18  use function in_array;
  19  use InvalidArgumentException;
  20  use function is_array;
  21  use JsonSerializable;
  22  
  23  class JWK implements JsonSerializable
  24  {
  25      /**
  26       * @var array
  27       */
  28      private $values = [];
  29  
  30      /**
  31       * Creates a JWK object using the given values.
  32       * The member "kty" is mandatory. Other members are NOT checked.
  33       *
  34       * @throws InvalidArgumentException if the key parameter "kty" is missing
  35       */
  36      public function __construct(array $values)
  37      {
  38          if (!isset($values['kty'])) {
  39              throw new InvalidArgumentException('The parameter "kty" is mandatory.');
  40          }
  41          $this->values = $values;
  42      }
  43  
  44      /**
  45       * Creates a JWK object using the given Json string.
  46       *
  47       * @throws InvalidArgumentException if the data is not valid
  48       *
  49       * @return JWK
  50       */
  51      public static function createFromJson(string $json): self
  52      {
  53          $data = json_decode($json, true);
  54          if (!is_array($data)) {
  55              throw new InvalidArgumentException('Invalid argument.');
  56          }
  57  
  58          return new self($data);
  59      }
  60  
  61      /**
  62       * Returns the values to be serialized.
  63       */
  64      public function jsonSerialize(): array
  65      {
  66          return $this->values;
  67      }
  68  
  69      /**
  70       * Get the value with a specific key.
  71       *
  72       * @param string $key The key
  73       *
  74       * @throws InvalidArgumentException if the key does not exist
  75       *
  76       * @return null|mixed
  77       */
  78      public function get(string $key)
  79      {
  80          if (!$this->has($key)) {
  81              throw new InvalidArgumentException(sprintf('The value identified by "%s" does not exist.', $key));
  82          }
  83  
  84          return $this->values[$key];
  85      }
  86  
  87      /**
  88       * Returns true if the JWK has the value identified by.
  89       *
  90       * @param string $key The key
  91       */
  92      public function has(string $key): bool
  93      {
  94          return array_key_exists($key, $this->values);
  95      }
  96  
  97      /**
  98       * Get all values stored in the JWK object.
  99       *
 100       * @return array Values of the JWK object
 101       */
 102      public function all(): array
 103      {
 104          return $this->values;
 105      }
 106  
 107      /**
 108       * Returns the thumbprint of the key.
 109       *
 110       * @see https://tools.ietf.org/html/rfc7638
 111       *
 112       * @throws InvalidArgumentException if the hashing function is not supported
 113       */
 114      public function thumbprint(string $hash_algorithm): string
 115      {
 116          if (!in_array($hash_algorithm, hash_algos(), true)) {
 117              throw new InvalidArgumentException(sprintf('The hash algorithm "%s" is not supported.', $hash_algorithm));
 118          }
 119          $values = array_intersect_key($this->values, array_flip(['kty', 'n', 'e', 'crv', 'x', 'y', 'k']));
 120          ksort($values);
 121          $input = json_encode($values, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
 122          if (false === $input) {
 123              throw new InvalidArgumentException('Unable to compute the key thumbprint');
 124          }
 125  
 126          return Base64Url::encode(hash($hash_algorithm, $input, true));
 127      }
 128  
 129      /**
 130       * Returns the associated public key.
 131       * This method has no effect for:
 132       * - public keys
 133       * - shared keys
 134       * - unknown keys.
 135       *
 136       * Known keys are "oct", "RSA", "EC" and "OKP".
 137       *
 138       * @return JWK
 139       */
 140      public function toPublic(): self
 141      {
 142          $values = array_diff_key($this->values, array_flip(['p', 'd', 'q', 'dp', 'dq', 'qi']));
 143  
 144          return new self($values);
 145      }
 146  }