public static function login($username, $password)
 {
     // Login to MAPI to check credentials
     $mapiSession = mapi_logon_zarafa($username, $password, ZARAFA_SERVER);
     if ($mapiSession == false) {
         return false;
     }
     Encryption::add('username', $username);
     Encryption::add('password', $password);
     Authentication::$_authenticated = true;
 }