Use of undefined constant CRYPT_SHA512

I use a php script that hashes passwords using php's crypt and uses SHA512, however when I try to check if SHA512 is set I get the above error. Of course I know WHY I get this error.. php is missing some dependency. I just don't know what that dependency is.

Can anyone please tell me what I need to i开发者_开发知识库nstall (on a Ubuntu server) to be able to use SHA512 in PHP ?

Thanks!

The php docs say that built-in support for SHA-256 and SHA-512 was added in PHP 5.3.2. If you use any earlier versions of PHP, it relies on implementations of those algorithms provided by your system, which apparently yours does not have.

Make sure you have newest version of PHP5 and install mcrypt - also contains alot of other encryption methods like rinjdael (AES)

Bottom line, you should be using mcrypt, not SHA512 or any md5 style hasher. It's too easy to brute force decrypt them. There is a ton of good reference at http://www.php.net/manual/en/function.mcrypt-generic.php and all over google. Below is an example of a 3DES hashed URL using the reference function urlsafe_b64encode from http://www.php.net/manual/en/function.mcrypt-generic.php#71135

$key = "what can i tell you";
$request = http_build_query($_REQUEST);
$request_enc = urlencode(urlsafe_b64encode(mcrypt_ecb(MCRYPT_3DES, $key, $request, MCRYPT_ENCRYPT)));
$url = "http://localhost/takemerightthere/".$request_enc;