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<?php
/**
* Pure-PHP implementation of RC4.
*
* Uses mcrypt, if available, and an internal implementation, otherwise.
*
* PHP version 5
*
* Useful resources are as follows:
*
* - {@link http://www.mozilla.org/projects/security/pki/nss/draft-kaukonen-cipher-arcfour-03.txt ARCFOUR Algorithm}
* - {@link http://en.wikipedia.org/wiki/RC4 - Wikipedia: RC4}
*
* RC4 is also known as ARCFOUR or ARC4. The reason is elaborated upon at Wikipedia. This class is named RC4 and not
* ARCFOUR or ARC4 because RC4 is how it is referred to in the SSH1 specification.
*
* Here's a short example of how to use this library:
* <code>
* <?php
* include 'vendor/autoload.php';
*
* $rc4 = new \phpseclib\Crypt\RC4();
*
* $rc4->setKey('abcdefgh');
*
* $size = 10 * 1024;
* $plaintext = '';
* for ($i = 0; $i < $size; $i++) {
* $plaintext.= 'a';
* }
*
* echo $rc4->decrypt($rc4->encrypt($plaintext));
* ?>
* </code>
*
* @category Crypt
* @package RC4
* @author Jim Wigginton <terrafrost@php.net>
* @copyright 2007 Jim Wigginton
* @license http://www.opensource.org/licenses/mit-license.html MIT License
* @link http://phpseclib.sourceforge.net
*/
namespace phpseclib\Crypt;
/**
* Pure-PHP implementation of RC4.
*
* @package RC4
* @author Jim Wigginton <terrafrost@php.net>
* @access public
*/
class RC4 extends Base
{
/**
* Turns key lengths, be they valid or invalid, to valid key lengths
*
* @param int $length
* @access private
* @return int
*/
protected function calculateNewKeyLength($length)
{
switch (true) {
case $length < 8:
return 8;
case $length > 2048:
return 2048;
}
return $length;
}
}
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