protected function _verify($value) {
        $queryString = http_build_query([
            'secret'   => $this->_secretKey,
            'response' => $value,
            'remoteIp' => $_SERVER['REMOTE_ADDR']
        ]);

        /**
         * PHP 5.6.0 changed the way you specify the peer name for SSL context options.
         * Using "CN_name" will still work, but it will raise deprecated errors.
         */
        $peerKey = version_compare(PHP_VERSION, '5.6.0', '<') ? 'CN_name' : 'peer_name';
        $context = stream_context_create([
            'http'  => [
                'header'      => "Content-type: application/x-www-form-urlencoded\r\n",
                'method'      => self::POST_METHOD,
                'content'     => $queryString,
                'verify_peer' => true,
                $peerKey      => self::PEER_KEY
            ]
        ]);
        $jsonObject = json_decode(file_get_contents(self::SITE_VERIFY_URL, false, $context));

        return $jsonObject->success;
    }