CryptLib/Cipher/Block/Mode/CFB.php

   1 <?php
   2 /**
   3  * The CFB (Cipher FeedBack) mode implementation
   4  *
   5  * PHP version 5.3
   6  *
   7  * @category   PHPCryptLib
   8  * @package    Cipher
   9  * @subpackage Block
  10  * @author     Anthony Ferrara <ircmaxell@ircmaxell.com>
  11  * @copyright  2011 The Authors
  12  * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
  13  * @version    Build @@version@@
  14  */
  15
  16 namespace CryptLib\Cipher\Block\Mode;
  17
  18 /**
  19  * The CFB (Cipher FeedBack) mode implementation
  20  *
  21  * @category   PHPCryptLib
  22  * @package    Cipher
  23  * @subpackage Block
  24  * @author     Anthony Ferrara <ircmaxell@ircmaxell.com>
  25  */
  26 class CFB extends \CryptLib\Cipher\Block\AbstractMode {
  27
  28     /**
  29      * Decrypt the data using the supplied key, cipher
  30      *
  31      * @param string $data The data to decrypt
  32      *
  33      * @return string The decrypted data
  34      */
  35     protected function decryptBlock($data) {
  36         $stub        = $this->cipher->encryptBlock($this->state);
  37         $rawData     = $stub ^ $data;
  38         $this->state = $rawData;
  39         return $rawData;
  40     }
  41
  42     /**
  43      * Encrypt the data using the supplied key, cipher
  44      *
  45      * @param string $data The data to encrypt
  46      *
  47      * @return string The encrypted data
  48      */
  49     protected function encryptBlock($data) {
  50         $stub        = $this->cipher->encryptBlock($this->state);
  51         $this->state = $data;
  52         return $stub ^ $data;
  53     }
  54
  55 }