Encryption and Decryption in PHP part : 2

Encryption and Decryption in PHP

<?php

$key = 'Your Key';
$string = 'My String'; // note the spaces

$encrypted = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($key), $string, MCRYPT_MODE_CBC, md5(md5($key))));

$decrypted = rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($key), base64_decode($encrypted), MCRYPT_MODE_CBC, md5(md5($key))), "\0");

echo 'Encrypted:' . "\n";
var_dump($encrypted);

echo "\n";

echo 'Decrypted:' . "\n";
var_dump($decrypted); // spaces are preserved

?>

Output : 

Origional : 'My String'

Encrypted:

string 'X7zPEx/hl2aMvBrK2+V3XJtqvQssSiYUQWTFyHlbjmQ=' (length=44)

Decrypted:

string 'My String' (length=9)