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   1  <?php
   2  
   3  /**
   4   * Pure-PHP implementation of AES.
   5   *
   6   * Uses mcrypt, if available/possible, and an internal implementation, otherwise.
   7   *
   8   * PHP version 5
   9   *
  10   * NOTE: Since AES.php is (for compatibility and phpseclib-historical reasons) virtually
  11   * just a wrapper to Rijndael.php you may consider using Rijndael.php instead of
  12   * to save one include_once().
  13   *
  14   * If {@link self::setKeyLength() setKeyLength()} isn't called, it'll be calculated from
  15   * {@link self::setKey() setKey()}.  ie. if the key is 128-bits, the key length will be 128-bits.  If it's 136-bits
  16   * it'll be null-padded to 192-bits and 192 bits will be the key length until {@link self::setKey() setKey()}
  17   * is called, again, at which point, it'll be recalculated.
  18   *
  19   * Since \phpseclib3\Crypt\AES extends \phpseclib3\Crypt\Rijndael, some functions are available to be called that, in the context of AES, don't
  20   * make a whole lot of sense.  {@link self::setBlockLength() setBlockLength()}, for instance.  Calling that function,
  21   * however possible, won't do anything (AES has a fixed block length whereas Rijndael has a variable one).
  22   *
  23   * Here's a short example of how to use this library:
  24   * <code>
  25   * <?php
  26   *    include 'vendor/autoload.php';
  27   *
  28   *    $aes = new \phpseclib3\Crypt\AES('ctr');
  29   *
  30   *    $aes->setKey('abcdefghijklmnop');
  31   *
  32   *    $size = 10 * 1024;
  33   *    $plaintext = '';
  34   *    for ($i = 0; $i < $size; $i++) {
  35   *        $plaintext.= 'a';
  36   *    }
  37   *
  38   *    echo $aes->decrypt($aes->encrypt($plaintext));
  39   * ?>
  40   * </code>
  41   *
  42   * @author    Jim Wigginton <terrafrost@php.net>
  43   * @copyright 2008 Jim Wigginton
  44   * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
  45   * @link      http://phpseclib.sourceforge.net
  46   */
  47  
  48  namespace phpseclib3\Crypt;
  49  
  50  /**
  51   * Pure-PHP implementation of AES.
  52   *
  53   * @author  Jim Wigginton <terrafrost@php.net>
  54   */
  55  class AES extends Rijndael
  56  {
  57      /**
  58       * Dummy function
  59       *
  60       * Since \phpseclib3\Crypt\AES extends \phpseclib3\Crypt\Rijndael, this function is, technically, available, but it doesn't do anything.
  61       *
  62       * @see \phpseclib3\Crypt\Rijndael::setBlockLength()
  63       * @param int $length
  64       * @throws \BadMethodCallException anytime it's called
  65       */
  66      public function setBlockLength($length)
  67      {
  68          throw new \BadMethodCallException('The block length cannot be set for AES.');
  69      }
  70  
  71      /**
  72       * Sets the key length
  73       *
  74       * Valid key lengths are 128, 192, and 256.  Set the link to bool(false) to disable a fixed key length
  75       *
  76       * @see \phpseclib3\Crypt\Rijndael:setKeyLength()
  77       * @param int $length
  78       * @throws \LengthException if the key length isn't supported
  79       */
  80      public function setKeyLength($length)
  81      {
  82          switch ($length) {
  83              case 128:
  84              case 192:
  85              case 256:
  86                  break;
  87              default:
  88                  throw new \LengthException('Key of size ' . $length . ' not supported by this algorithm. Only keys of sizes 128, 192 or 256 supported');
  89          }
  90          parent::setKeyLength($length);
  91      }
  92  
  93      /**
  94       * Sets the key.
  95       *
  96       * Rijndael supports five different key lengths, AES only supports three.
  97       *
  98       * @see \phpseclib3\Crypt\Rijndael:setKey()
  99       * @see setKeyLength()
 100       * @param string $key
 101       * @throws \LengthException if the key length isn't supported
 102       */
 103      public function setKey($key)
 104      {
 105          switch (strlen($key)) {
 106              case 16:
 107              case 24:
 108              case 32:
 109                  break;
 110              default:
 111                  throw new \LengthException('Key of size ' . strlen($key) . ' not supported by this algorithm. Only keys of sizes 16, 24 or 32 supported');
 112          }
 113  
 114          parent::setKey($key);
 115      }
 116  }