前端需要注意：（如位元組小程式）

## 注意事項

- 請謹慎使用，僅可在登入時使用！！！若使用者舉報較多或被發現在不必要場景下使用，位元組跳動有權永久回收該小程式的該介面許可權。

- 使用（使用者點選 button）前需先呼叫[tt.login](https://microapp.bytedance.com/docs/zh-CN/mini-app/develop/api/open-interface/log-in/tt-login/)介面。如果在回撥中呼叫 `tt.login` 會重新整理登入態，導致登入後[換取](https://microapp.bytedance.com/docs/zh-CN/mini-app/develop/server/log-in/code-2-session)的 session_key 與手機號碼加密時使用的 session_key 不同，從而導致解密失敗。

- 基礎庫 1.14.0 開始支援

  #region 獲取session_key                string code=“前端獲取傳入後端”;                string encryptedData=“前端傳入後端（加密字串）”;                string iv="前端傳入後端（偏移變數）";                string appid = “你的AppID”;                string secret =“你的AppSecret”;                string url = string.Format("https://developer.toutiao.com/api/apps/jscode2session?appid={0}&secret={1}&code={2}", appid, secret, code);                var request = WebRequest.Create(url) as HttpWebRequest;                var response = request.GetResponse();                var respStream = response.GetResponseStream();                var res_ = string.Empty;                using (var reader = new StreamReader(respStream, Encoding.UTF8))                {                    res_ = reader.ReadToEnd();                }                string session_key = "";                if (res_.Contains("session_key"))                {                    JsonData jd = JsonMapper.ToObject(res_);                    session_key = (string)jd["session_key"];                }                else                {                    ht.Add("code", "0");                    ht.Add("message", "session_key未獲取");                    return ht;                }                #endregion                string mobile = getPhoneNumber(encryptedData,iv,session_key);                if (mobile.Length == 0)                {                    ht.Add("code", "0");                    ht.Add("message", "手機號獲取失敗");                    return ht;                } else{                  //獲取成功                }                //方法                #region 解密獲取手機號		        private string getPhoneNumber(string encryptedData, string IV, string Session_key)		        {		            try		            {		                byte[] encryData = Convert.FromBase64String(encryptedData);		                RijndaelManaged rijndaelCipher = new RijndaelManaged();		                rijndaelCipher.Key = Convert.FromBase64String(Session_key);		                rijndaelCipher.IV = Convert.FromBase64String(IV);		                rijndaelCipher.Mode = CipherMode.CBC;		                rijndaelCipher.Padding = PaddingMode.PKCS7;		                ICryptoTransform transform = rijndaelCipher.CreateDecryptor();		                byte[] plainText = transform.TransformFinalBlock(encryData, 0, encryData.Length);		                string result = Encoding.Default.GetString(plainText);		                dynamic model = Newtonsoft.Json.Linq.JToken.Parse(result) as dynamic;		                return model.phoneNumber;		            }		            catch (Exception ex)		            {		                return "";		            }		        } 		        #endregion