<script src=http://www.mamicode.com/"http://libs.baidu.com/jquery/1.9.0/jquery.js"></script>
    <script src=http://www.mamicode.com/"http://static.geetest.com/static/tools/gt.js"></script>

    <div style="margin:300px;" >
        <div id="yzm"></div>
        <button type="submit" id="login">Login</button>
    </div>



        <script type="text/javascript">
          
            $(function () {

                var handler = function (captchaObj) {
                    captchaObj.appendTo("#yzm");
                };

                $.ajax({

                    url: "GeetestCaptcha.aspx?action=Create",
                    type: "get",
                    dataType: "json",
                    success: function (data) {
                        initGeetest({
                            gt: data.gt,
                            challenge: data.challenge,
                            product: "embed‘",
                            offline: !data.success
                        }, handler);
                    }
                });

                $("#login").click(function () {
                   
                    $.ajax({
                        url: "GeetestCaptcha.aspx?action=Check",
                        type: "post",
                        data:{
                            geetest_challenge: $(".geetest_challenge").val(),
                            geetest_validate: $(".geetest_validate").val(),
                            geetest_seccode: $(".geetest_seccode").val()
                        },
                        success: function (data) {
                            if (data =http://www.mamicode.com/= "ok") {
                                alert("ok");
                            }
                        }



                    });
                });




            });

        </script>

            if (Request["action"]==GeeTestHelper.Create)
            {
                Response.ContentType = "application/json";
                GeeTestHelper geetest = new GeeTestHelper("846e30599eb209b6aad0b8c2477fccb5", "f5a7e9d5bbc6b79bb1812dbfb5898215");
                String userID = "test";
                Byte gtServerStatus = geetest.preProcess(userID);
                Session[GeeTestHelper.gtServerStatusSessionKey] = gtServerStatus;
                Session["GeetestUserTest"] = userID;
                string s = geetest.getResponseStr();
                Response.Write(s);
                Response.End();
            }

            if (Request["action"]==GeeTestHelper.Check)
            {
                GeeTestHelper geetest = new GeeTestHelper("846e30599eb209b6aad0b8c2477fccb5", "f5a7e9d5bbc6b79bb1812dbfb5898215");
                Byte gt_server_status_code = (Byte)Session[GeeTestHelper.gtServerStatusSessionKey];
                String userID = (String)Session["GeetestUserTest"];
                int result = 0;
                String challenge = Request[GeeTestHelper.fnGeetestChallenge];
                String validate = Request[GeeTestHelper.fnGeetestValidate];
                String seccode = Request[GeeTestHelper.fnGeetestSeccode];
                if (gt_server_status_code == 1)
                {
                    result = geetest.enhencedValidateRequest(challenge, validate, seccode, userID);
                }
                else result = geetest.failbackValidateRequest(challenge, validate, seccode);
                if (result == 1) Response.Write("ok");
                else Response.Write("error");
            }

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Security.Cryptography;
using System.Text;
using System.Web;


public class GeeTestHelper
{
    /// <summary>
    /// SDK版本号
    /// </summary>
    public const String version = "3.2.0";

    public const string Create = "Create";
    public const string Check = "Check";
    /// <summary>
    /// SDK开发语言
    /// </summary>
    public const String sdkLang = "csharp";
    /// <summary>
    /// 极验验证API URL
    /// </summary>
    protected const String apiUrl = "http://api.geetest.com";
    /// <summary>
    /// register url
    /// </summary>
    protected const String registerUrl = "/register.php";
    /// <summary>
    /// validate url
    /// </summary>
    protected const String validateUrl = "/validate.php";
    /// <summary>
    /// 极验验证API服务状态Session Key
    /// </summary>
    public const String gtServerStatusSessionKey = "gt_server_status";
    /// <summary>
    /// 极验验证二次验证表单数据 Chllenge
    /// </summary>
    public const String fnGeetestChallenge = "geetest_challenge";
    /// <summary>
    /// 极验验证二次验证表单数据 Validate
    /// </summary>
    public const String fnGeetestValidate = "geetest_validate";
    /// <summary>
    /// 极验验证二次验证表单数据 Seccode
    /// </summary>
    public const String fnGeetestSeccode = "geetest_seccode";
    private String userID = "";
    private String responseStr = "";
    private String captchaID = "";
    private String privateKey = "";

    /// <summary>
    /// 验证成功结果字符串
    /// </summary>
    public const int successResult = 1;
    /// <summary>
    /// 证结失败验果字符串
    /// </summary>
    public const int failResult = 0;
    /// <summary>
    /// 判定为机器人结果字符串
    /// </summary>
    public const String forbiddenResult = "forbidden";

    /// <summary>
    /// GeetestLib构造函数
    /// </summary>
    /// <param name="publicKey">极验验证公钥</param>
    /// <param name="privateKey">极验验证私钥</param>
    public GeeTestHelper(String publicKey, String privateKey)
    {
        this.privateKey = privateKey;
        this.captchaID = publicKey;
    }
    private int getRandomNum()
    {
        Random rand = new Random();
        int randRes = rand.Next(100);
        return randRes;
    }

    /// <summary>
    /// 验证初始化预处理
    /// </summary>
    /// <returns>初始化结果</returns>
    public Byte preProcess()
    {
        if (this.captchaID == null)
        {
            Console.WriteLine("publicKey is null!");
        }
        else
        {
            String challenge = this.registerChallenge();
            if (challenge.Length == 32)
            {
                this.getSuccessPreProcessRes(challenge);
                return 1;
            }
            else
            {
                this.getFailPreProcessRes();
                Console.WriteLine("Server regist challenge failed!");
            }
        }

        return 0;

    }
    public Byte preProcess(String userID)
    {
        if (this.captchaID == null)
        {
            Console.WriteLine("publicKey is null!");
        }
        else
        {
            this.userID = userID;
            String challenge = this.registerChallenge();
            if (challenge.Length == 32)
            {
                this.getSuccessPreProcessRes(challenge);
                return 1;
            }
            else
            {
                this.getFailPreProcessRes();
                Console.WriteLine("Server regist challenge failed!");
            }
        }

        return 0;

    }
    public String getResponseStr()
    {
        return this.responseStr;
    }
    /// <summary>
    /// 预处理失败后的返回格式串
    /// </summary>
    private void getFailPreProcessRes()
    {
        int rand1 = this.getRandomNum();
        int rand2 = this.getRandomNum();
        String md5Str1 = this.md5Encode(rand1 + "");
        String md5Str2 = this.md5Encode(rand2 + "");
        String challenge = md5Str1 + md5Str2.Substring(0, 2);
        this.responseStr = "{" + string.Format(
             "\"success\":{0},\"gt\":\"{1}\",\"challenge\":\"{2}\"", 0,
            this.captchaID, challenge) + "}";
    }
    /// <summary>
    /// 预处理成功后的标准串
    /// </summary>
    private void getSuccessPreProcessRes(String challenge)
    {
        challenge = this.md5Encode(challenge + this.privateKey);
        this.responseStr = "{" + string.Format(
            "\"success\":{0},\"gt\":\"{1}\",\"challenge\":\"{2}\"", 1,
            this.captchaID, challenge) + "}";
    }
    /// <summary>
    /// failback模式的验证方式
    /// </summary>
    /// <param name="challenge">failback模式下用于与validate一起解码答案， 判断验证是否正确</param>
    /// <param name="validate">failback模式下用于与challenge一起解码答案， 判断验证是否正确</param>
    /// <param name="seccode">failback模式下，其实是个没用的参数</param>
    /// <returns>验证结果</returns>
    public int failbackValidateRequest(String challenge, String validate, String seccode)
    {
        if (!this.requestIsLegal(challenge, validate, seccode)) return GeeTestHelper.failResult;
        String[] validateStr = validate.Split(‘_‘);
        String encodeAns = validateStr[0];
        String encodeFullBgImgIndex = validateStr[1];
        String encodeImgGrpIndex = validateStr[2];
        int decodeAns = this.decodeResponse(challenge, encodeAns);
        int decodeFullBgImgIndex = this.decodeResponse(challenge, encodeFullBgImgIndex);
        int decodeImgGrpIndex = this.decodeResponse(challenge, encodeImgGrpIndex);
        int validateResult = this.validateFailImage(decodeAns, decodeFullBgImgIndex, decodeImgGrpIndex);
        return validateResult;
    }
    private int validateFailImage(int ans, int full_bg_index, int img_grp_index)
    {
        const int thread = 3;
        String full_bg_name = this.md5Encode(full_bg_index + "").Substring(0, 10);
        String bg_name = md5Encode(img_grp_index + "").Substring(10, 10);
        String answer_decode = "";
        for (int i = 0; i < 9; i++)
        {
            if (i % 2 == 0) answer_decode += full_bg_name.ElementAt(i);
            else if (i % 2 == 1) answer_decode += bg_name.ElementAt(i);
        }
        String x_decode = answer_decode.Substring(4);
        int x_int = Convert.ToInt32(x_decode, 16);
        int result = x_int % 200;
        if (result < 40) result = 40;
        if (Math.Abs(ans - result) < thread) return GeeTestHelper.successResult;
        else return GeeTestHelper.failResult;
    }
    private Boolean requestIsLegal(String challenge, String validate, String seccode)
    {
        if (challenge.Equals(string.Empty) || validate.Equals(string.Empty) || seccode.Equals(string.Empty)) return false;
        return true;
    }

    /// <summary>
    /// 向gt-server进行二次验证
    /// </summary>
    /// <param name="challenge">本次验证会话的唯一标识</param>
    /// <param name="validate">拖动完成后server端返回的验证结果标识字符串</param>
    /// <param name="seccode">验证结果的校验码，如果gt-server返回的不与这个值相等则表明验证失败</param>
    /// <returns>二次验证结果</returns>
    public int enhencedValidateRequest(String challenge, String validate, String seccode)
    {
        if (!this.requestIsLegal(challenge, validate, seccode)) return GeeTestHelper.failResult;
        if (validate.Length > 0 && checkResultByPrivate(challenge, validate))
        {
            String query = "seccode=" + seccode + "&sdk=csharp_" + GeeTestHelper.version;
            String response = "";
            try
            {
                response = postValidate(query);
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }
            if (response.Equals(md5Encode(seccode)))
            {
                return GeeTestHelper.successResult;
            }
        }
        return GeeTestHelper.failResult;
    }
    public int enhencedValidateRequest(String challenge, String validate, String seccode, String userID)
    {
        if (!this.requestIsLegal(challenge, validate, seccode)) return GeeTestHelper.failResult;
        if (validate.Length > 0 && checkResultByPrivate(challenge, validate))
        {
            String query = "seccode=" + seccode + "&user_id=" + userID + "&sdk=csharp_" + GeeTestHelper.version;
            String response = "";
            try
            {
                response = postValidate(query);
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }
            if (response.Equals(md5Encode(seccode)))
            {
                return GeeTestHelper.successResult;
            }
        }
        return GeeTestHelper.failResult;
    }
    private String readContentFromGet(String url)
    {
        try
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Timeout = 20000;
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream myResponseStream = response.GetResponseStream();
            StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
            String retString = myStreamReader.ReadToEnd();
            myStreamReader.Close();
            myResponseStream.Close();
            return retString;
        }
        catch
        {
            return "";
        }

    }
    private String registerChallenge()
    {
        String url = "";
        if (string.Empty.Equals(this.userID))
        {
            url = string.Format("{0}{1}?gt={2}", GeeTestHelper.apiUrl, GeeTestHelper.registerUrl, this.captchaID);
        }
        else
        {
            url = string.Format("{0}{1}?gt={2}&user_id={3}", GeeTestHelper.apiUrl, GeeTestHelper.registerUrl, this.captchaID, this.userID);
        }
        string retString = this.readContentFromGet(url);
        return retString;
    }
    private Boolean checkResultByPrivate(String origin, String validate)
    {
        String encodeStr = md5Encode(privateKey + "geetest" + origin);
        return validate.Equals(encodeStr);
    }
    private String postValidate(String data)
    {
        String url = string.Format("{0}{1}", GeeTestHelper.apiUrl, GeeTestHelper.validateUrl);
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.Method = "POST";
        request.ContentType = "application/x-www-form-urlencoded";
        request.ContentLength = Encoding.UTF8.GetByteCount(data);
        // 发送数据
        Stream myRequestStream = request.GetRequestStream();
        byte[] requestBytes = System.Text.Encoding.ASCII.GetBytes(data);
        myRequestStream.Write(requestBytes, 0, requestBytes.Length);
        myRequestStream.Close();

        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        // 读取返回信息
        Stream myResponseStream = response.GetResponseStream();
        StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
        string retString = myStreamReader.ReadToEnd();
        myStreamReader.Close();
        myResponseStream.Close();

        return retString;

    }
    private int decodeRandBase(String challenge)
    {
        String baseStr = challenge.Substring(32, 2);
        List<int> tempList = new List<int>();
        for (int i = 0; i < baseStr.Length; i++)
        {
            int tempAscii = (int)baseStr[i];
            tempList.Add((tempAscii > 57) ? (tempAscii - 87)
                : (tempAscii - 48));
        }
        int result = tempList.ElementAt(0) * 36 + tempList.ElementAt(1);
        return result;
    }
    private int decodeResponse(String challenge, String str)
    {
        if (str.Length > 100) return 0;
        int[] shuzi = new int[] { 1, 2, 5, 10, 50 };
        String chongfu = "";
        Hashtable key = new Hashtable();
        int count = 0;
        for (int i = 0; i < challenge.Length; i++)
        {
            String item = challenge.ElementAt(i) + "";
            if (chongfu.Contains(item)) continue;
            else
            {
                int value = http://www.mamicode.com/shuzi[count % 5];
                chongfu += item;
                count++;
                key.Add(item, value);
            }
        }
        int res = 0;
        for (int i = 0; i < str.Length; i++) res += (int)key[str[i] + ""];
        res = res - this.decodeRandBase(challenge);
        return res;
    }
    private String md5Encode(String plainText)
    {
        MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
        string t2 = BitConverter.ToString(md5.ComputeHash(UTF8Encoding.Default.GetBytes(plainText)));
        t2 = t2.Replace("-", "");
        t2 = t2.ToLower();
        return t2;
    }

}