note 87274 added to ref.mcrypt
| From: | RafaelM dot Salvioni at osu1 dot php dot net | Date: | Thu, 27 Nov 2008 12:26:20 +0000 |
| Subject: | note 87274 added to ref.mcrypt | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-147032@lists.php.net to get a copy of this message | ||
The follow function is a implementation of the RC4 cypher algorithm in pure PHP code.
The function is used to encrypt and decrypt data.
<?php
/**
* Crypt/decrypt strings with RC4 stream cypher algorithm.
*
* @param string $key Key
* @param string $data Encripted/pure data
* @see http://pt.wikipedia.org/wiki/RC4
* @return string
*/
function rc4($key, $data)
{
// Store the vectors "S" has calculated
static $SC;
// Function to swaps values of the vector "S"
$swap = create_function('&$v1, &$v2', '
$v1 = $v1 ^ $v2;
$v2 = $v1 ^ $v2;
$v1 = $v1 ^ $v2;
');
$ikey = crc32($key);
if (!isset($SC[$ikey])) {
// Make the vector "S", basead in the key
$S = range(0, 255);
$j = 0;
$n = strlen($key);
for ($i = 0; $i < 255; $i++) {
$char = ord($key{$i % $n});
$j = ($j + $S[$i] + $char) % 256;
$swap($S[$i], $S[$j]);
}
$SC[$ikey] = $S;
} else {
$S = $SC[$ikey];
}
// Crypt/decrypt the data
$n = strlen($data);
$data = str_split($data, 1);
$i = $j = 0;
for ($m = 0; $m < $n; $m++) {
$i = ($i + 1) % 256;
$j = ($j + $S[$i]) % 256;
$swap($S[$i], $S[$j]);
$char = ord($data[$m]);
$char = $S[($S[$i] + $S[$j]) % 256] ^ $char;
$data[$m] = chr($char);
}
return implode('', $data);
}
?>
----
Server IP: 69.147.83.197
Probable Submitter: 201.28.8.198
----
Manual Page -- http://www.php.net/manual/en/ref.mcrypt.php
Edit -- https://master.php.net/note/edit/87274
Del: integrated -- https://master.php.net/note/delete/87274/integrated
Del: useless -- https://master.php.net/note/delete/87274/useless
Del: bad code -- https://master.php.net/note/delete/87274/bad+code
Del: spam -- https://master.php.net/note/delete/87274/spam
Del: non-english -- https://master.php.net/note/delete/87274/non-english
Del: in docs -- https://master.php.net/note/delete/87274/in+docs
Del: other reasons-- https://master.php.net/note/delete/87274
Reject -- https://master.php.net/note/reject/87274
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