note 105166 deleted from function.mcrypt-encrypt by nikic
| From: | nikic@php.net | Date: | Sat, 09 Nov 2013 11:13:29 +0000 |
| Subject: | note 105166 deleted from function.mcrypt-encrypt by nikic | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-197475@lists.php.net to get a copy of this message | ||
Note Submitter: antonio dot daeliminare dot bonifati at gmail dot com
----
Simple DES-ECB binary string encryption/decryption (no initialization vector). I implement
PKCS7-padding the right way. This is better than Mcrypt default zero-padding.
<?php
function encrypt($str, $key)
{
# Add PKCS7 padding.
$block = mcrypt_get_block_size('des', 'ecb');
if (($pad = $block - (strlen($str) % $block)) < $block) {
$str .= str_repeat(chr($pad), $pad);
}
return mcrypt_encrypt(MCRYPT_DES, $key, $str, MCRYPT_MODE_ECB);
}
function decrypt($str, $key)
{
$str = mcrypt_decrypt(MCRYPT_DES, $key, $str, MCRYPT_MODE_ECB);
# Strip padding out.
$block = mcrypt_get_block_size('des', 'ecb');
$pad = ord($str[($len = strlen($str)) - 1]);
if ($pad && $pad < $block && preg_match(
'/' . chr($pad) . '{' . $pad . '}$/', $str
)
) {
return substr($str, 0, strlen($str) - $pad);
}
return $str;
}
?>
I am using these functions to encrypt query strings:
<?php
const KEY = "\xc8\xd9\xb9\x06\xd9\xe8\xc9\xd2"; # Change this
# Send encrypted GET query string
$query = encrypt('field1=value1&field2=value2', KEY);
echo '<a href="script.php?' . urlencode($query) .
'">link</a>';
# Receive encrypted GET query string
$query = decrypt(urldecode($_SERVER['QUERY_STRING']), KEY);
parse_str($query, $query);
$query = filter_var_array($query, array(...));
?>