a brute-force MD5 cracker

Debug output:

'); echo('
');
$goodtext = "Not found yet.";
// if MD5 not set yet, this code is skipped
if ( isset($_GET['md5']) ) {
    $time_pre = microtime(true);
    $md5 = $_GET['md5'];

    // available letters to decode
    $txt = "abcdefghijklmnopqrstuvwxyz1234567890";
    $show = 25;

    // nested loops for comparing first, second, third, fourth characters to possible values
    for($i=0; $i 0 ) {
                        echo("$check $try\n");
                        $show = $show - 1;
                    }
                }
            }
        }
    }
    // Compute and display elapsed time
    $time_post = microtime(true);
    echo("Total time elapsed: ".($time_post-$time_pre));
    echo('
'); } ?>

Your secret code was: