<?php
$td = mcrypt_module_open(MCRYPT_CAST_256, '', MCRYPT_MODE_CFB, '');
echo mcrypt_enc_get_algorithms_name($td). "\n";
$td = mcrypt_module_open('cast-256', '', MCRYPT_MODE_CFB, '');
echo mcrypt_enc_get_algorithms_name($td). "\n";
?>
The above example will output: