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   1  <?php
   2  /**
   3   * PHPExcel
   4   *
   5   * Copyright (c) 2006 - 2014 PHPExcel
   6   *
   7   * This library is free software; you can redistribute it and/or
   8   * modify it under the terms of the GNU Lesser General Public
   9   * License as published by the Free Software Foundation; either
  10   * version 2.1 of the License, or (at your option) any later version.
  11   *
  12   * This library is distributed in the hope that it will be useful,
  13   * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15   * Lesser General Public License for more details.
  16   *
  17   * You should have received a copy of the GNU Lesser General Public
  18   * License along with this library; if not, write to the Free Software
  19   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  20   *
  21   * @category   PHPExcel
  22   * @package    PHPExcel_Reader_Excel5
  23   * @copyright  Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
  24   * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
  25   * @version    ##VERSION##, ##DATE##
  26   */
  27  
  28  /**
  29   * PHPExcel_Reader_Excel5_RC4
  30   *
  31   * @category    PHPExcel
  32   * @package        PHPExcel_Reader_Excel5
  33   * @copyright    Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
  34   */
  35  class PHPExcel_Reader_Excel5_RC4
  36  {
  37      // Context
  38      var $s = array();
  39      var $i = 0;
  40      var $j = 0;
  41  
  42      /**
  43       * RC4 stream decryption/encryption constrcutor
  44       * 
  45       * @param string $key Encryption key/passphrase
  46       */
  47  	public function __construct($key)
  48      {
  49          $len = strlen($key);
  50  
  51          for ($this->i = 0; $this->i < 256; $this->i++) {
  52              $this->s[$this->i] = $this->i;
  53          }
  54  
  55          $this->j = 0;
  56          for ($this->i = 0; $this->i < 256; $this->i++) {
  57              $this->j = ($this->j + $this->s[$this->i] + ord($key[$this->i % $len])) % 256;
  58              $t = $this->s[$this->i];
  59              $this->s[$this->i] = $this->s[$this->j];
  60              $this->s[$this->j] = $t;
  61          }
  62          $this->i = $this->j = 0;
  63      }
  64  
  65      /**
  66       * Symmetric decryption/encryption function
  67       * 
  68       * @param string $data Data to encrypt/decrypt
  69       * 
  70       * @return string
  71       */
  72  	public function RC4($data)
  73      {
  74          $len = strlen($data);
  75          for ($c = 0; $c < $len; $c++) {
  76              $this->i = ($this->i + 1) % 256;
  77              $this->j = ($this->j + $this->s[$this->i]) % 256;
  78              $t = $this->s[$this->i];
  79              $this->s[$this->i] = $this->s[$this->j];
  80              $this->s[$this->j] = $t;
  81  
  82              $t = ($this->s[$this->i] + $this->s[$this->j]) % 256;
  83  
  84              $data[$c] = chr(ord($data[$c]) ^ $this->s[$t]);
  85          }
  86          return $data;
  87      }
  88  }