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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 \phpseclib\Crypt\AES extends \phpseclib\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 \phpseclib\Crypt\AES();
  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   * @category  Crypt
  43   * @package   AES
  44   * @author    Jim Wigginton <terrafrost@php.net>
  45   * @copyright 2008 Jim Wigginton
  46   * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
  47   * @link      http://phpseclib.sourceforge.net
  48   */
  49  
  50  namespace phpseclib\Crypt;
  51  
  52  /**
  53   * Pure-PHP implementation of AES.
  54   *
  55   * @package AES
  56   * @author  Jim Wigginton <terrafrost@php.net>
  57   * @access  public
  58   */
  59  class AES extends Rijndael
  60  {
  61      /**
  62       * Dummy function
  63       *
  64       * Since \phpseclib\Crypt\AES extends \phpseclib\Crypt\Rijndael, this function is, technically, available, but it doesn't do anything.
  65       *
  66       * @see \phpseclib\Crypt\Rijndael::setBlockLength()
  67       * @access public
  68       * @param int $length
  69       */
  70      function setBlockLength($length)
  71      {
  72          return;
  73      }
  74  
  75      /**
  76       * Sets the key length
  77       *
  78       * Valid key lengths are 128, 192, and 256.  If the length is less than 128, it will be rounded up to
  79       * 128.  If the length is greater than 128 and invalid, it will be rounded down to the closest valid amount.
  80       *
  81       * @see \phpseclib\Crypt\Rijndael:setKeyLength()
  82       * @access public
  83       * @param int $length
  84       */
  85      function setKeyLength($length)
  86      {
  87          switch ($length) {
  88              case 160:
  89                  $length = 192;
  90                  break;
  91              case 224:
  92                  $length = 256;
  93          }
  94          parent::setKeyLength($length);
  95      }
  96  
  97      /**
  98       * Sets the key.
  99       *
 100       * Rijndael supports five different key lengths, AES only supports three.
 101       *
 102       * @see \phpseclib\Crypt\Rijndael:setKey()
 103       * @see setKeyLength()
 104       * @access public
 105       * @param string $key
 106       */
 107      function setKey($key)
 108      {
 109          parent::setKey($key);
 110  
 111          if (!$this->explicit_key_length) {
 112              $length = strlen($key);
 113              switch (true) {
 114                  case $length <= 16:
 115                      $this->key_length = 16;
 116                      break;
 117                  case $length <= 24:
 118                      $this->key_length = 24;
 119                      break;
 120                  default:
 121                      $this->key_length = 32;
 122              }
 123              $this->_setEngine();
 124          }
 125      }
 126  }