public function getImageUrl()
    {
        $config = \OxidEsales\Eshop\Core\Registry::getConfig();
        $url = $config->getCurrentShopUrl() . 'modules/oe/captcha/core/utils/verificationimg.php?e_mac=';
        $key = $config->getConfigParam('oecaptchakey');

        $key = $key ? $key : $config->getConfigParam('sConfigKey');

        $encryptor = new \OxidEsales\Eshop\Core\Encryptor();
        $url .= $encryptor->encrypt($this->getText(), $key);

        return $url;
    }