<?PHP
$username = mysql_real_escape_string( $_POST['username'] );
$password = md5(sha1(md5(md5(sha1( mysql_real_escape_string($_POST['password']))))));
$sql = mysql_query("INSERT INTO users (username, password) VALUES ( '$username', '$password')");
$bot = mysql_real_escape_string( $_POST['bot'] );
if ( $bot != htmlspecialchars(13) )
    {

        echo 'Mathematical sum correct! Wow! You are good in maths!<br />';
        echo "You have been registered!";

    }
else
    {

       echo 'Sorry. You got the mathematical sum wrong. How bad are you in math?';

    }
mysql_close($core);
?>