[PHP] Mcrypt 암호화/복호화

function encrypt($string,$key) {
srand((double) microtime() * 1000000);
$key = md5($key);
$td = mcrypt_module_open('des', '','cfb', '');
$key = substr($key, 0, mcrypt_enc_get_key_size($td));
$iv_size = mcrypt_enc_get_iv_size($td);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
if (mcrypt_generic_init($td, $key, $iv) != -1) {
$c_t = mcrypt_generic($td, $string);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
$c_t = $iv.$c_t;
return $c_t;
}
}

$id= encrypt(english,title);

<a href=view.php?id=<?=htmlentities(urlencode($id))?>>view</a>

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view.php 내용

function decrypt($string,$key) {
$key = md5($key);
$td = mcrypt_module_open('des', '','cfb', '');
$key = substr($key, 0, mcrypt_enc_get_key_size($td));
$iv_size = mcrypt_enc_get_iv_size($td);
$iv = substr($string,0,$iv_size);
$string = substr($string,$iv_size);
if (mcrypt_generic_init($td, $key, $iv) != -1) {
$c_t = mdecrypt_generic($td, $string);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
return $c_t;
}
}

echo decrypt($_REQUEST['id'],title);