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src/lib/PHPExcel/Reader/Excel5/RC4.php 2.38 KB
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  <?php
  /**
   * PHPExcel
   *
   * Copyright (c) 2006 - 2014 PHPExcel
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   *
   * @category   PHPExcel
   * @package    PHPExcel_Reader_Excel5
   * @copyright  Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
   * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt	LGPL
   * @version    1.8.0, 2014-03-02
   */
  
  /**
   * PHPExcel_Reader_Excel5_RC4
   *
   * @category	PHPExcel
   * @package		PHPExcel_Reader_Excel5
   * @copyright	Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
   */
  class PHPExcel_Reader_Excel5_RC4
  {
  	// Context
  	var $s = array();
  	var $i = 0;
  	var $j = 0;
  
  	/**
  	 * RC4 stream decryption/encryption constrcutor
  	 * 
  	 * @param string $key Encryption key/passphrase
  	 */
  	public function __construct($key)
  	{
  		$len = strlen($key);
  
  		for ($this->i = 0; $this->i < 256; $this->i++) {
  			$this->s[$this->i] = $this->i;
  		}
  
  		$this->j = 0;
  		for ($this->i = 0; $this->i < 256; $this->i++) {
  			$this->j = ($this->j + $this->s[$this->i] + ord($key[$this->i % $len])) % 256;
  			$t = $this->s[$this->i];
  			$this->s[$this->i] = $this->s[$this->j];
  			$this->s[$this->j] = $t;
  		}
  		$this->i = $this->j = 0;
  	}
  
  	/**
  	 * Symmetric decryption/encryption function
  	 * 
  	 * @param string $data Data to encrypt/decrypt
  	 * 
  	 * @return string
  	 */
  	public function RC4($data)
  	{
  		$len = strlen($data);
  		for ($c = 0; $c < $len; $c++) {
  			$this->i = ($this->i + 1) % 256;
  			$this->j = ($this->j + $this->s[$this->i]) % 256;
  			$t = $this->s[$this->i];
  			$this->s[$this->i] = $this->s[$this->j];
  			$this->s[$this->j] = $t;
  
  			$t = ($this->s[$this->i] + $this->s[$this->j]) % 256;
  
  			$data[$c] = chr(ord($data[$c]) ^ $this->s[$t]);
  		}
  		return $data;
  	}
  }