protected function _lockReferrer(KControllerContextInterface $context)
    {
        $cookie = $this->getObject('lib:http.cookie', array(
            'name'   => $this->_cookie_name.'_locked',
            'value'  => true,
            'path'   => $this->_cookie_path
        ));

        $context->response->headers->addCookie($cookie);
    }