$qwerty = 'qwertyuiopasdfghjklzxcvbnm' . 'QWERTYUIOPASDFGHJKLZXCVBNM';
$dvorak = 'abcdefghijklmnopqrstuvwxyz' . 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
$message = "Start the attack when the sun rises.";
$encoded = strtr($message, $qwerty, $dvorak);
$decoded = strtr($encoded, $dvorak, $qwerty);
?>