<?php
    $modes = mcrypt_list_modes();
    foreach ($modes as $mode) {
        echo "$mode <br />\n";
    }
?>
     
    
     The above example will produce a list with all supported
     algorithms in the default mode directory. If it is not set
     with the ini directive mcrypt.modes_dir, the default directory
     of mcrypt is used (which is /usr/local/lib/libmcrypt).