rc4.inc in Simplenews Statistics 6.2

RC4 symmetric cipher encryption/decryption Copyright (c) 2006 by Ali Farhadi. released under the terms of the Gnu Public License. see the GPL for details.

Email: ali[at]farhadi[dot]ir Website: http://farhadi.ir/

File

rc4.inc

<?php

// $Id: rc4.inc,v 1.1 2009/09/28 14:08:33 docc Exp $

/**
 * @file
 * RC4 symmetric cipher encryption/decryption
 * Copyright (c) 2006 by Ali Farhadi.
 * released under the terms of the Gnu Public License.
 * see the GPL for details.
 *
 * Email: ali[at]farhadi[dot]ir
 * Website: http://farhadi.ir/
 */

/**
 * Encrypt given plain text using the key with RC4 algorithm.
 * All parameters and return value are in binary format.
 *
 * @param string key - secret key for encryption
 * @param string pt - plain text to be encrypted
 * @return string
 */
function rc4Encrypt($key, $pt) {
  $s = array();
  for ($i = 0; $i < 256; $i++) {
    $s[$i] = $i;
  }
  $j = 0;
  $x;
  for ($i = 0; $i < 256; $i++) {
    $j = ($j + $s[$i] + ord($key[$i % strlen($key)])) % 256;
    $x = $s[$i];
    $s[$i] = $s[$j];
    $s[$j] = $x;
  }
  $i = 0;
  $j = 0;
  $ct = '';
  $y;
  for ($y = 0; $y < strlen($pt); $y++) {
    $i = ($i + 1) % 256;
    $j = ($j + $s[$i]) % 256;
    $x = $s[$i];
    $s[$i] = $s[$j];
    $s[$j] = $x;
    $ct .= $pt[$y] ^ chr($s[($s[$i] + $s[$j]) % 256]);
  }
  return $ct;
}

/**
 * Decrypt given cipher text using the key with RC4 algorithm.
 * All parameters and return value are in binary format.
 *
 * @param string key - secret key for decryption
 * @param string ct - cipher text to be decrypted
 * @return string
*/
function rc4Decrypt($key, $ct) {
  return rc4Encrypt($key, $ct);
}

Functions

Name	Description
rc4Decrypt	Decrypt given cipher text using the key with RC4 algorithm. All parameters and return value are in binary format.
rc4Encrypt	Encrypt given plain text using the key with RC4 algorithm. All parameters and return value are in binary format.