애플릿에서 사용자 휴대폰 번호 서버측 코드 가져오기 (C#)

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


public class AverageHandler : IHttpHandler
{
public bool IsReusable
{ get { return true; } }

public void ProcessRequest(HttpContext ctx)
{
    ctx.Response.ContentType = "application/json";
    HttpRequest Request = ctx.Request;
    string text = Request["encryptedData"];
    string IV = Request["iv"];

    //   appid appsecret  
    string appid = "       ";
    string secret = "       ";

    string code = Request["code"];//         
    Stream s_re = WebRequest.Create("https://api.weixin.qq.com/sns/jscode2session?appid="+appid+"&secret="+secret+"&js_code="+code+"&grant_type=authorization_code").GetResponse().GetResponseStream();
    StreamReader sr = new StreamReader(s_re, Encoding.UTF8);
    string strLine = sr.ReadToEnd();
    sr.Close();
    try
    {
        JsonData jo = JsonMapper.ToObject(strLine);
        string Key = jo["session_key"].ToString();
        //string weixinID = jo["openid"].ToString();
        string str= AES_decrypt(text,Key,IV);
        ctx.Response.Write(str);
     }
        catch (Exception ex)
     {
         //return "";

     }

}

public string AES_decrypt(string encryptedDataStr, string key, string iv)  
        {  
            RijndaelManaged rijalg = new RijndaelManaged();  
            //-----------------    
            //   cipher    AES-128-CBC    
  
            rijalg.KeySize = 128;  
  
            rijalg.Padding = PaddingMode.PKCS7;  
            rijalg.Mode = CipherMode.CBC;  
  
            rijalg.Key = Convert.FromBase64String(key);  
            rijalg.IV = Convert.FromBase64String(iv);  
  
  
            byte[] encryptedData= Convert.FromBase64String(encryptedDataStr);  
            //      
            ICryptoTransform decryptor = rijalg.CreateDecryptor(rijalg.Key, rijalg.IV);  
  
            string result;  
              
            using (MemoryStream msDecrypt = new MemoryStream(encryptedData))  
            {  
                using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))  
                {  
                    using (StreamReader srDecrypt = new StreamReader(csDecrypt))  
                    {  
  
                        result = srDecrypt.ReadToEnd();  
                    }  
                }  
            }  
  
            return result;  
        }

  

}