public static function getToken($launch) {
        global $CFG;
        if ( ! isset($CFG->websocket_secret) || strlen($CFG->websocket_secret) < 1 ) return false;
        $plain = self::makeToken($launch);
        if ( ! $plain ) return $plain;
        $encrypted = AesCtr::encrypt($plain, $CFG->websocket_secret, 256) ;
        return $encrypted;
    }