public function passCaptcha($displayError = true)
    {
        $return = true;

        // spam spider prevention
        $mac = $this->getConfig()->getRequestParameter('c_mac');
        $macHash = $this->getConfig()->getRequestParameter('c_mach');

        if (!$this->pass($mac, $macHash)) {
            $return = false;
        }

        if (!$return && $displayError) {
            // even if there is no exception, use this as a default display method
            oxRegistry::get('oxUtilsView')->addErrorToDisplay('MESSAGE_WRONG_VERIFICATION_CODE');
        }

        return $return;
    }