recaptcha

[HttpPost]
public void Method(MyData data, string challenge, string response)
{
    string recaptchaValidationUrl = "http://www.google.com/recaptcha/api/verify";
    string privateKey = "MY_RECAPTCHA_PRIVATE_KEY";

    if (!CheckRecaptcha(recaptchaValidationUrl, request.RcChallenge, request.RcResponse, privateKey,
    HttpContext.Current.Request.UserHostAddress))
    {
        return new FindTechResResponse { ErrorMessage = "Invalid captcha code" };
    }
}

public static bool CheckRecaptcha(string recaptchaValidationUrl, string challenge, string response, string privateKey, string clientIp)
{
    using (WebClient webClient = new WebClient())
    {
        NameValueCollection data = new NameValueCollection();
        data["privatekey"] = privateKey;
        data["remoteip"] = clientIp;
        data["challenge"] = challenge;
        data["response"] = response;

        byte[] responseBytes = webClient.UploadValues(recaptchaValidationUrl, "POST", data);
        string responseString = Encoding.UTF8.GetString(responseBytes);
        string isSolvedString = responseString.Split('\n')[0];
        bool isSolved = bool.Parse(isSolvedString);
        return isSolved;
        }
    }
}