Système de connexion avec base de donnée by @akumatereure

<?php
<!-- Salut pour les Fainéant voici le code :) ♥♥♥ . PS:allez me follow sur Twitter @AkumaTereure -->
<!-- il faut changer les endroits ou il y a ecrit A Remplacer!! par votre propre Base de donnée,Utilisateur MYSQL et Mot de passe" -->
$sessionID = $GET["sessionID"];
$actionget = $_GET["action"];
$user = $GET["user"];
$password = $GET["password"];
$registerKey = $GET["registerKey"];

if (empty($sessionID)) die ("ERROR:INVALID_SESSION_ID");


$action = new action;
if ($actionget == "connect")
    $response = $action->connect($user, $password);
elseif ($actionget == "register")
$response = $action->register($user, $password, $registerKey);
else
$response = "ERROR:NO_ACTION";
echo rc4($sessionID, $response);

class action
{
    public $bdd;

    public function action()
        {
        try { $this->bdd = new PDO('mysql:host=localhost;dbname=A Remplacer!!', 'A Remplacer!!', 'A remplacer!!') ; }
        catch (Exception $ex) { die('ERROR_BDD_CONNECTION'); }
        }
        public function connect ($user, $pass)

        {
            if (!$this->userExist($user)) return ("ERROR:USER_NOT_FOUND");

            $data = $this->executeQuery("SELECT * FROM Users WHERE User = ?;", array($user));
            if ($data['Password'] != md5($pass))
                return ("ERROR:INCORRECT_PASSWORD");
            elseif ($data['Banned'] ==1)
            return ("ERROR:USER_BANNED");
            else
                return ("OK:") . $data['Prenium'];
        }

        public function register ($user, $pass, $register)
        {
            $data = $this->executeQuery("SELECT * FROM Register Keys WHERE RegisterKey = ?;", array($registerKey));
            if (empty($data['RegisterKey'])) return ("ERROR:INVALID_KEY");
            if (!empty($data['User'])) return ("ERROR:KEY_ALREADY_USED");
            if ($this->userExist ($user)) return ("ERROR:USER_ALREADY_EXIST");

            $this->executeQuery("INSERT INTO User VALUES (' ', ?, ?, '0', '0', ?);", array($user,md5($pass), getTime()));
            $this->executeQuery("UPDATE RegisterKeys SET User = ? WHERE RegisterKey = ?;", array($user, $registerKey));

            return ("OK:REGISTERED");

        }

        private function userExist($user)
        {
            $data == $this->executeQuery("SELECT *FROM Users WHERE User = ?;", array($user));
            if (empty($data['User']))
                return (false);
            else return (true);

        }


        private function executeQuery($query, $args, $fetch = true)
        {
            $response = $this->bdd->prepare(query);
            $response->execute ($args);
            if ($fetch)
            {
                $data = $response->fetch();
                $response->closeCursor();
                return ($data);
            }
            else
                return ($response);
        }
}

function rc4($key, $str) {
$s = array();
for ($i = 0; $i < 256; $i++) {
$s[$i] = $i;
}

$j = 0;

for ($i = 0; $i < 256; $i++) {
$j = ($j + $s[$i] + ord($key[$i % strlen($key)])) % 256;
$x = $s[$i];
$s[$i] = $s[$j];
$s[$j] = $x;
}

$i = 0;
$j = 0;
$res = '';

for ($y = 0; $y < strlen($str); $y++) {
$i = ($i + 1) % 256;
$j = ($j + $s[$i]) % 256;
$x = $s[$i];
$s[$i] = $s[$j];
$s[$j] = $x;
$res .= $str[$y] ^ chr($s[($s[$i] + $s[$j]) % 256]);
}

return $res;
}






function getTime ()
{
    date_default_timezone_set('Europe/Paris');
    return date("Y-m-d H:i:s");
}

?>