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) }