mcrypt
PHP Manual

mcrypt_enc_get_supported_key_sizes

(PHP 4 >= 4.0.2, PHP 5)

mcrypt_enc_get_supported_key_sizes — Returns an array with the supported keysizes of the opened algorithm

Description

array mcrypt_enc_get_supported_key_sizes ( resource $td )

Returns an array with the key sizes supported by the algorithm specified by the encryption descriptor. If it returns an empty array then all key sizes between 1 and mcrypt_enc_get_key_size() are supported by the algorithm.

Example#1 mcrypt_enc_get_supported_key_sizes() example

<?php
    $td 
mcrypt_module_open('rijndael-256''''ecb''');
    
var_dump(mcrypt_enc_get_supported_key_sizes($td));
?>

This will print:

array(3) { [0]=> int(16) [1]=> int(24) [2]=> int(32) }


mcrypt
PHP Manual