Encrypted:

"‘¾N%–œ·¤Õj‰W±I©®Î‹ñ`û0

Decrypted:

This is very important data



The code:

<?php

    /* Open the cipher */
    $td = mcrypt_module_open('rijndael-256', '', 'ofb', '');

    /* Create the IV and determine the keysize length */
    $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_DEV_RANDOM);
    $ks = mcrypt_enc_get_key_size($td);

    /* Create key with a little added computational complexity */
    $key = substr(md5(md5(md5(md5(md5('very secret key'))))), 0, $ks);

    /* Intialize encryption */
    mcrypt_generic_init($td, $key, $iv);

    /* Encrypt data */
    $encrypted = mcrypt_generic($td, 'This is very important data');

    /* Show encrypted data */
    echo "<h2>Encrypted:</h2>$encrypted<br />";

    /* Terminate encryption handler */
    mcrypt_generic_deinit($td);

    /* Initialize encryption module for decryption */
    mcrypt_generic_init($td, $key, $iv);

    /* Decrypt encrypted string */
    $decrypted = mdecrypt_generic($td, $encrypted);

    /* Terminate decryption handle and close module */
    mcrypt_generic_deinit($td);
    mcrypt_module_close($td);

    /* Show string */
    echo "<h2>Decrypted:</h2>" . trim($decrypted);

?>