mcrypt_enc_get_supported_key_sizes

Description

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.

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

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