[Sommaire] [Imprimer]

   1  <?php
   2  /**
   3   * The Horde_Cipher_BlockMode_ecb:: This class implements the
   4   * Horde_Cipher_BlockMode using the Electronic Code Book method of
   5   * encrypting blocks of data.
   6   *
   7   * $Horde: framework/Cipher/Cipher/BlockMode/ecb.php,v 1.7.12.5 2006/01/01 21:28:11 jan Exp $
   8   *
   9   * Copyright 2002-2006 Mike Cochrane <mike@graftonhall.co.nz>
  10   *
  11   * See the enclosed file COPYING for license information (LGPL). If you
  12   * did not receive this file, see http://www.fsf.org/copyleft/lgpl.html.
  13   *
  14   * @author  Mike Cochrane <mike@graftonhall.co.nz>
  15   * @since   Horde 2.2
  16   * @package Horde_Cipher
  17   */
  18  class Horde_Cipher_BlockMode_ecb extends Horde_Cipher_BlockMode {
  19  
  20      /**
  21       * Encrypt a string.
  22       *
  23       * @param Horde_Cipher $cipher  Cipher algorithm to use for
  24       *                              encryption.
  25       * @param string $plaintext     The data to encrypt.
  26       *
  27       * @return  The encrypted data.
  28       */
  29      function encrypt(&$cipher, $plaintext)
  30      {
  31          $encrypted = '';
  32          $blocksize = $cipher->getBlockSize();
  33  
  34          $jMax = strlen($plaintext);
  35          for ($j = 0; $j < $jMax; $j += $blocksize) {
  36              $plain = substr($plaintext, $j, $blocksize);
  37  
  38              if (strlen($plain) < $blocksize) {
  39                  // pad the block with \0's if it's not long enough
  40                  $plain = str_pad($plain, 8, "\0");
  41              }
  42  
  43              $encrypted .= $cipher->encryptBlock($plain);
  44          }
  45  
  46          return $encrypted;
  47      }
  48  
  49      /**
  50       * Decrypt a string.
  51       *
  52       * @param Horde_Cipher $cipher  Cipher algorithm to use for
  53       *                              decryption.
  54       * @param string $ciphertext    The data to decrypt.
  55       *
  56       * @return  The decrypted data.
  57       */
  58      function decrypt(&$cipher, $ciphertext)
  59      {
  60          $decrypted = '';
  61          $blocksize = $cipher->getBlockSize();
  62  
  63          $jMax = strlen($ciphertext);
  64          for ($j = 0; $j < $jMax; $j += $blocksize) {
  65              $plain = substr($ciphertext, $j, $blocksize);
  66              $decrypted .= $cipher->decryptBlock($plain);
  67          }
  68  
  69          // Remove trailing \0's used to pad the last block.
  70          while (substr($decrypted, -1, 1) == "\0") {
  71              $decrypted = substr($decrypted, 0, -1);
  72          }
  73  
  74          return $decrypted;
  75      }
  76  
  77  }