Validate Recaptcha

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Net;
using System.IO;
using System.Web.Mvc;

namespace WeBlog.Core {
  public static class RecaptchaUtils {
    public static JsonResult ValidateRecaptcha( string privateKey, string remoteip, string challenge, string response) {
      string postData = String.Format("privatekey={0}&remoteip={1}&challenge={2}&response={3}",
                            privateKey, remoteip,
                            challenge, response);
      JsonResult result = new JsonResult();
      byte[] postDataBuffer = System.Text.Encoding.ASCII.GetBytes(postData);

      Uri serviceUri = new Uri("http://api-verify.recaptcha.net/verify", UriKind.Absolute);
      try {
        HttpWebRequest webRequest = (HttpWebRequest)System.Net.WebRequest.Create(serviceUri);
        webRequest.ContentType = "application/x-www-form-urlencoded";
        webRequest.ContentLength = postDataBuffer.Length;
        webRequest.Method = "POST";

        //incase you are using a proxy server
        IWebProxy proxy = WebRequest.GetSystemWebProxy();
        proxy.Credentials = System.Net.CredentialCache.DefaultCredentials;
        webRequest.Proxy = proxy;

        Stream requestStream = webRequest.GetRequestStream();
        requestStream.Write(postDataBuffer, 0, postDataBuffer.Length);

        HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse();
        string jsonResponse = string.Empty;

        using (StreamReader sr = new StreamReader(webResponse.GetResponseStream()))
          jsonResponse = sr.ReadToEnd();

        string[] tokens = jsonResponse.Split(new char[] { '\n' });
        if (tokens.Length == 2) {
          Boolean success = tokens[0].Equals("true", StringComparison.CurrentCulture);
          result.Data = new { Success = success, Message = tokens[1] };
        }
        else {
          result.Data = new { Success = false, Message = "Invalid response returned" };
        }
      }
      catch (Exception ex) {
        result.Data = new { Success = false, Message = ex.Message };
      }

      return result;
    }
  }
}