public function generate()
    {
        $sClientKey = appSetting('site_key_client', 'nails/driver-captcha-recaptcha');

        if (empty($sClientKey)) {
            throw new CaptchaDriverException('ReCaptcha not configured.');
        }

        $oAsset = Factory::service('Asset');
        $oAsset->load('https://www.google.com/recaptcha/api.js');

        $oResponse = Factory::factory('CaptchaForm', 'nails/module-captcha');
        $oResponse->setHtml('<div class="g-recaptcha" data-sitekey="' . $sClientKey . '"></div>');

        return $oResponse;
    }