vendor/phpoffice/phpexcel/Classes/PHPExcel/Reader/Excel5/RC4.php

   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 }