微信开放平台(消息加解密接入指引)

消息加解密接入指引

开发者在代替授权公众号接收和处理消息时,出于安全考虑,必须对消息收发的过程进行必须的加解密。该文档讲述如何使用示例代码接入加解密,参考本文档并使用示例代码,加解密的接入将非常简单。若想进一步的了解细节,请查看 《公众号第三方平台的加密解密技术方案》

首先请注意,开发者在接收消息和事件时,都需要进行消息加解密(某些事件可能需要回复,回复时也需要先进行加密)。但是,通过API主动调用接口(包括调用客服消息接口发消息)时,不需要进行加密。

消息类型

公众号第三方平台可能会接收到两种类型的消息:

1、用户发送给公众号的消息(由公众号第三方平台代收)。此时,消息XML体中,ToUserName(即接收者)为公众号的原始ID(可通过《接口说明》中的获取授权方信息接口来获得)。

2、微信服务器发送给服务自身的事件推送(如取消授权通知,Ticket推送等)。此时,消息XML体中没有ToUserName字段,而是AppId字段,即公众号服务的AppId。这种系统事件推送通知(现在包括推送component_verify_ticket协议和推送取消授权通知),服务开发者收到后也需进行解密,接收到后只需直接返回字符串“success”。

开发者可以在微信公众平台接口调试工具,在接口类型中选择“消息接口调试”,并选择安全模式的加密调试,进行消息加解密的在线调试。

具体消息加解密的做法是,当关注者与已授权公众号进行交互时,公众号第三方平台将接收到相应的消息推送、事件推送。为了加强安全性,将对此过程进行2个措施:

1、在接收已授权公众号消息和事件的URL中,增加2个参数(此前已有2个参数,为时间戳 timestamp,随机数nonce),分别是encrypt_type(加密类型,为aes)和msg_signature(消息体签名,用于验证消息体的正确性)

2、postdata中的XML体,将使用第三方平台申请时的接收消息的加密symmetric_key(也称为EncodingAESKey)来进行加密。

示例代码

微信公众平台提供了c++, php, java, python, c# 5种语言的示例代码(点击下载,请运行示例代码前先阅读对应的readme文件),每种语言的类名和接口名均一致,下面以C++为例说明。

1.函数说明

1.1. 构造函数

// @param sToken: 第三方平台申请时填写的接收消息的校验token
// @param sEncodingAESKey: 第三方平台申请时填写的接收消息的加密symmetric_key
// @param sAppid: 公众号第三方平台的appidWXBizMsgCrypt(const std::string &sToken,
const std::string &sEncodingAESKey,
const std::string &sAppid)

1.2. 解密函数

// 检验消息的真实性,并且获取解密后的明文
// @param sMsgSignature: 签名串,对应URL参数的msg_signature
// @param sTimeStamp: 时间戳,对应URL参数的timestamp
// @param sNonce: 随机串,对应URL参数的nonce
// @param sPostData: 密文,对应POST请求的数据
// @param sMsg: 解密后的明文,当return返回0时有效
// @return: 成功0,失败返回对应的错误码
int DecryptMsg(const std::string &sMsgSignature,
const std::string &sTimeStamp,
const std::string &sNonce,
const std::string &sPostData,
std::string &sMsg);

1.3. 加密函数

//将公众号回复用户的消息加密打包
// @param sReplyMsg:公众号待回复用户的消息,xml格式的字符串
// @param sTimeStamp: 时间戳,可以自己生成,也可以用URL参数的timestamp
// @param sNonce: 随机串,可以自己生成,也可以用URL参数的nonce
// @param sEncryptMsg: 加密后的可以直接回复用户的密文,包括msg_signature, timestamp, nonce,encrypt的xml格式的字符串,当return返回0时有效
// return:成功0,失败返回对应的错误码
int EncryptMsg(const std::string &sReplyMsg,
const std::string &sTimeStamp,
const std::string &sNonce,
std::string &sEncryptMsg);

2. 使用方法

2.1 实例化对象

使用构造函数,实例化一个对象,传入公众号第三方平台的token(申请公众号第三方平台时填写的接收消息的校验token), 公众号第三方平台的appid, 公众号第三方平台的 EncodingAESKey(申请公众号第三方平台时填写的接收消息的加密symmetric_key

2.2 解密
安全模式下,第三方平台方收到以下带密文消息体:

encrypt_msg =
<xml>
<ToUserName></ToUserName>
<Encrypt></Encrypt>
</xml>

调用示例代码中的DecryptMsg函数(需传入msg_signature、timetamp、noncepostdata,前3个参数可从接收已授权公众号消息和事件的URL中获得,postdata即为POST过来的数据包内容),若调用成功,sMsg则为输出结果,其内容为如下的明文的xml消息体:

<xml>
<ToUserName></ToUserName>
<FromUserName></FromUserName>
<CreateTime>1411035097</CreateTime>
<MsgType></MsgType>
<Content></Content>
<MsgId>6060349595123187712</MsgId>
</xml>

2.3 公众帐号处理消息,生成需要回复给微信公众平台的xml消息体,假设回复以下内容:

res_msg =
<xml>
<ToUserName></ToUserName>
<FromUserName></FromUserName>
<CreateTime>1411034505</CreateTime>
<MsgType></MsgType>
<Content></Content>
<FuncFlag>0</FuncFlag>
</xml>

2.4 回包加密

调用EncryptMsg接口,传入需要回复给微信公众平台的res_msg, timestamp, nonce, 若加密成功,则sEncryptMsg为密文消息体,内容如下:

<xml>
<Encrypt>
<![CDATA[LDFAmKFr7U/RMmwRbsR676wjym90byw7+hhh226e8bu6KVYy00HheIsVER4eMgz/VBtofSaeXXQBz6fVdkN2CzBUaTtjJeTCXEIDfTBNxpw/QRLGLq
qMZHA3I+JiBxrrSzd2yXuXst7TdkVgY4lZEHQcWk85x1niT79XLaWQog+OnBV31eZbXGPPv8dZciKqGo0meTYi+fkMEJdyS8OE7NjO79vpIyIw7hMBtEXPBK/tJGN5m5SoAS
6I4rRZ8Zl8umKxXqgr7N8ZOs6DB9tokpvSl9wT9T3E62rufaKP5EL1imJUd1pngxy09EP24O8Th4bCrdUcZpJio2l11vE6bWK2s5WrLuO0cKY2GP2unQ4fDxh0L4ePmNOVFJ
wp9Hyvd0BAsleXA4jWeOMw5nH3Vn49/Q/ZAQ2HN3dB0bMA+6KJYLvIzTz/Iz6vEjk8ZkK+AbhW5eldnyRDXP/OWfZH2P3WQZUwc/G/LGmS3ekqMwQThhS2Eg5t4yHv0mAIei
07Lknip8nnwgEeF4R9hOGutE9ETsGG4CP1LHTQ4fgYchOMfB3wANOjIt9xendbhHbu51Z4OKnA0F+MlgZomiqweT1v/+LUxcsFAZ1J+Vtt0FQXElDKg+YyQnRCiLl3I+GJ/c
xSj86XwClZC3NNhAkVU11SvxcXEYh9smckV/qRP2Acsvdls0UqZVWnPtzgx8hc8QBZaeH+JeiaPQD88frNvA==]]> </Encrypt>
<MsgSignature></MsgSignature>
<TimeStamp>1411034505</TimeStamp>
<Nonce></Nonce>
</xml>

3. 注意事项

1.EncodingAESKey长度固定为43个字符,从a-z,A-Z,0-9共62个字符中选取。

2.出于安全考虑,开放平台网站提供了修改EncodingAESKey的功能(在EncodingAESKey可能泄漏时进行修改),所以建议公众账号保存当前的和上一次的EncodingAESKey,若当前EncodingAESKey解密失败,则尝试用上一次的EncodingAESKey的解密。回包时,用哪个Key解密成功,则用此Key加密对应的回包。

消息解密流程图:
在这里插入图片描述


微信官方示例

注意事项

  1. Cryptography.cs文件封装了AES加解密过程,用户无须关心具体实现。WXBizMsgCrypt.cs文件提供了用户接入企业微信的两个接口,Sample.cs文件提供了如何使用这两个接口的示例。
  2. WXBizMsgCrypt.cs封装了DecryptMsg, EncryptMsg两个接口,分别用于收到用户回复消息的解密以及开发者回复消息的加密过程。使用方法可以参考Sample.cs文件。
  3. 加解密协议请参考微信公众平台官方文档。

Sample.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
namespace MsgCryptTest
{
    class Sample
    {
        static void Main(string[] args)
        {
            //公众平台上开发者设置的token, appID, EncodingAESKey
            string sToken = "QDG6eK";
            string sAppID = "wx5823bf96d3bd56c7";
            string sEncodingAESKey = "jWmYm7qr5nMoAUwZRjGtBxmz3KA1tkAj3ykkR6q2B2C";

            Tencent.WXBizMsgCrypt wxcpt = new Tencent.WXBizMsgCrypt(sToken, sEncodingAESKey, sAppID);
            
             /* 1. 对用户回复的数据进行解密。
             * 用户回复消息或者点击事件响应时,企业会收到回调消息,假设企业收到的推送消息:
             * 	POST /cgi-bin/wxpush? msg_signature=477715d11cdb4164915debcba66cb864d751f3e6&timestamp=1409659813&nonce=1372623149 HTTP/1.1
	            Host: qy.weixin.qq.com
                Content-Length: 613
             *
             * 	<xml>
	                <ToUserName><![CDATA[wx5823bf96d3bd56c7]]></ToUserName>
	                <Encrypt><![CDATA[RypEvHKD8QQKFhvQ6QleEB4J58tiPdvo+rtK1I9qca6aM/wvqnLSV5zEPeusUiX5L5X/0lWfrf0QADHHhGd3QczcdCUpj911L3vg3W/sYYvuJTs3TUUkSUXxaccAS0qhxchrRYt66wiSpGLYL42aM6A8dTT+6k4aSknmPj48kzJs8qLjvd4Xgpue06DOdnLxAUHzM6+kDZ+HMZfJYuR+LtwGc2hgf5gsijff0ekUNXZiqATP7PF5mZxZ3Izoun1s4zG4LUMnvw2r+KqCKIw+3IQH03v+BCA9nMELNqbSf6tiWSrXJB3LAVGUcallcrw8V2t9EL4EhzJWrQUax5wLVMNS0+rUPA3k22Ncx4XXZS9o0MBH27Bo6BpNelZpS+/uh9KsNlY6bHCmJU9p8g7m3fVKn28H3KDYA5Pl/T8Z1ptDAVe0lXdQ2YoyyH2uyPIGHBZZIs2pDBS8R07+qN+E7Q==]]></Encrypt>
                </xml>
             */
            string sReqMsgSig = "477715d11cdb4164915debcba66cb864d751f3e6";
            string sReqTimeStamp = "1409659813";
            string sReqNonce = "1372623149";
            string sReqData = "<xml><ToUserName><![CDATA[wx5823bf96d3bd56c7]]></ToUserName><Encrypt><![CDATA[RypEvHKD8QQKFhvQ6QleEB4J58tiPdvo+rtK1I9qca6aM/wvqnLSV5zEPeusUiX5L5X/0lWfrf0QADHHhGd3QczcdCUpj911L3vg3W/sYYvuJTs3TUUkSUXxaccAS0qhxchrRYt66wiSpGLYL42aM6A8dTT+6k4aSknmPj48kzJs8qLjvd4Xgpue06DOdnLxAUHzM6+kDZ+HMZfJYuR+LtwGc2hgf5gsijff0ekUNXZiqATP7PF5mZxZ3Izoun1s4zG4LUMnvw2r+KqCKIw+3IQH03v+BCA9nMELNqbSf6tiWSrXJB3LAVGUcallcrw8V2t9EL4EhzJWrQUax5wLVMNS0+rUPA3k22Ncx4XXZS9o0MBH27Bo6BpNelZpS+/uh9KsNlY6bHCmJU9p8g7m3fVKn28H3KDYA5Pl/T8Z1ptDAVe0lXdQ2YoyyH2uyPIGHBZZIs2pDBS8R07+qN+E7Q==]]></Encrypt></xml>";
            string sMsg = "";  //解析之后的明文
			int ret = 0;
            ret = wxcpt.DecryptMsg(sReqMsgSig, sReqTimeStamp, sReqNonce, sReqData, ref sMsg);
            if (ret != 0)
            {
                System.Console.WriteLine("ERR: Decrypt fail, ret: " + ret);
                return;
            }
            System.Console.WriteLine(sMsg);


            /*
             * 2. 企业回复用户消息也需要加密和拼接xml字符串。
             * 假设企业需要回复用户的消息为:
             * 		<xml>
             * 		<ToUserName><![CDATA[mycreate]]></ToUserName>
             * 		<FromUserName><![CDATA[wx5823bf96d3bd56c7]]></FromUserName>
             * 		<CreateTime>1348831860</CreateTime>
                    <MsgType><![CDATA[text]]></MsgType>
             *      <Content><![CDATA[this is a test]]></Content>
             *      <MsgId>1234567890123456</MsgId>
             *      </xml>
             * 生成xml格式的加密消息过程为:
             */
            string sRespData = "<xml><ToUserName><![CDATA[mycreate]]></ToUserName><FromUserName><![CDATA[wx582测试一下中文的情况,消息长度是按字节来算的396d3bd56c7]]></FromUserName><CreateTime>1348831860</CreateTime><MsgType><![CDATA[text]]></MsgType><Content><![CDATA[this is a test]]></Content><MsgId>1234567890123456</MsgId></xml>";
            string sEncryptMsg = ""; //xml格式的密文
            ret = wxcpt.EncryptMsg(sRespData, sReqTimeStamp, sReqNonce, ref sEncryptMsg);
            System.Console.WriteLine("sEncryptMsg");
            System.Console.WriteLine(sEncryptMsg);

            /*测试:
             * 将sEncryptMsg解密看看是否是原文
             * */
            XmlDocument doc = new XmlDocument();
            doc.LoadXml(sEncryptMsg);
            XmlNode root = doc.FirstChild;
            string sig = root["MsgSignature"].InnerText;
            string enc = root["Encrypt"].InnerText;
            string timestamp = root["TimeStamp"].InnerText;
            string nonce = root["Nonce"].InnerText;
            string stmp = "";
            ret = wxcpt.DecryptMsg(sig, timestamp, nonce, sEncryptMsg, ref stmp);
            System.Console.WriteLine("stemp");
            System.Console.WriteLine(stmp + ret);
            return;
        }
    }
}

WXBizMsgCrypt.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Collections;
//using System.Web;
using System.Security.Cryptography;
//-40001 : 签名验证错误
//-40002 :  xml解析失败
//-40003 :  sha加密生成签名失败
//-40004 :  AESKey 非法
//-40005 :  appid 校验错误
//-40006 :  AES 加密失败
//-40007 : AES 解密失败
//-40008 : 解密后得到的buffer非法
//-40009 :  base64加密异常
//-40010 :  base64解密异常
namespace Tencent
{
    class WXBizMsgCrypt
    {
        string m_sToken;
        string m_sEncodingAESKey;
        string m_sAppID;
        enum WXBizMsgCryptErrorCode
        {
            WXBizMsgCrypt_OK = 0,
            WXBizMsgCrypt_ValidateSignature_Error = -40001,
            WXBizMsgCrypt_ParseXml_Error = -40002,
            WXBizMsgCrypt_ComputeSignature_Error = -40003,
            WXBizMsgCrypt_IllegalAesKey = -40004,
            WXBizMsgCrypt_ValidateAppid_Error = -40005,
            WXBizMsgCrypt_EncryptAES_Error = -40006,
            WXBizMsgCrypt_DecryptAES_Error = -40007,
            WXBizMsgCrypt_IllegalBuffer = -40008,
            WXBizMsgCrypt_EncodeBase64_Error = -40009,
            WXBizMsgCrypt_DecodeBase64_Error = -40010
        };

        //构造函数
	    // @param sToken: 公众平台上,开发者设置的Token
	    // @param sEncodingAESKey: 公众平台上,开发者设置的EncodingAESKey
	    // @param sAppID: 公众帐号的appid
        public WXBizMsgCrypt(string sToken, string sEncodingAESKey, string sAppID)
        {
            m_sToken = sToken;
            m_sAppID = sAppID;
            m_sEncodingAESKey = sEncodingAESKey;
        }


        // 检验消息的真实性,并且获取解密后的明文
        // @param sMsgSignature: 签名串,对应URL参数的msg_signature
        // @param sTimeStamp: 时间戳,对应URL参数的timestamp
        // @param sNonce: 随机串,对应URL参数的nonce
        // @param sPostData: 密文,对应POST请求的数据
        // @param sMsg: 解密后的原文,当return返回0时有效
        // @return: 成功0,失败返回对应的错误码
        public int DecryptMsg(string sMsgSignature, string sTimeStamp, string sNonce, string sPostData, ref string sMsg)
        {
			if (m_sEncodingAESKey.Length!=43)
			{
				return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_IllegalAesKey;
			}
            XmlDocument doc = new XmlDocument();
            XmlNode root;
            string sEncryptMsg;
            try
            {
                doc.LoadXml(sPostData);
                root = doc.FirstChild;
                sEncryptMsg = root["Encrypt"].InnerText;
            }
            catch (Exception)
            {
                return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_ParseXml_Error;
            }
            //verify signature
            int ret = 0;
            ret = VerifySignature(m_sToken, sTimeStamp, sNonce, sEncryptMsg, sMsgSignature);
            if (ret != 0)
                return ret;
            //decrypt
            string cpid = "";
            try
            {
                sMsg = Cryptography.AES_decrypt(sEncryptMsg, m_sEncodingAESKey, ref cpid);
            }
            catch (FormatException)
            {
                return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_DecodeBase64_Error;
            }
            catch (Exception)
            {
                return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_DecryptAES_Error;
            }
            if (cpid != m_sAppID)
                return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_ValidateAppid_Error;
            return 0;
        }

        //将企业号回复用户的消息加密打包
        // @param sReplyMsg: 企业号待回复用户的消息,xml格式的字符串
        // @param sTimeStamp: 时间戳,可以自己生成,也可以用URL参数的timestamp
        // @param sNonce: 随机串,可以自己生成,也可以用URL参数的nonce
        // @param sEncryptMsg: 加密后的可以直接回复用户的密文,包括msg_signature, timestamp, nonce, encrypt的xml格式的字符串,
        //						当return返回0时有效
        // return:成功0,失败返回对应的错误码
        public int EncryptMsg(string sReplyMsg, string sTimeStamp, string sNonce, ref string sEncryptMsg)
        {
			if (m_sEncodingAESKey.Length!=43)
			{
				return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_IllegalAesKey;
			}
            string raw = "";
            try
            {
                raw = Cryptography.AES_encrypt(sReplyMsg, m_sEncodingAESKey, m_sAppID);
            }
            catch (Exception)
            {
                return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_EncryptAES_Error;
            }
            string MsgSigature = "";
            int ret = 0;
            ret = GenarateSinature(m_sToken, sTimeStamp, sNonce, raw, ref MsgSigature);
            if (0 != ret)
                return ret;
            sEncryptMsg = "";

            string EncryptLabelHead = "<Encrypt><![CDATA[";
            string EncryptLabelTail = "]]></Encrypt>";
            string MsgSigLabelHead = "<MsgSignature><![CDATA[";
            string MsgSigLabelTail = "]]></MsgSignature>";
            string TimeStampLabelHead = "<TimeStamp><![CDATA[";
            string TimeStampLabelTail = "]]></TimeStamp>";
            string NonceLabelHead = "<Nonce><![CDATA[";
            string NonceLabelTail = "]]></Nonce>";
            sEncryptMsg = sEncryptMsg + "<xml>" + EncryptLabelHead + raw + EncryptLabelTail;
            sEncryptMsg = sEncryptMsg + MsgSigLabelHead + MsgSigature + MsgSigLabelTail;
            sEncryptMsg = sEncryptMsg + TimeStampLabelHead + sTimeStamp + TimeStampLabelTail;
            sEncryptMsg = sEncryptMsg + NonceLabelHead + sNonce + NonceLabelTail;
            sEncryptMsg += "</xml>";
            return 0;
        }

        public class DictionarySort : System.Collections.IComparer
        {
            public int Compare(object oLeft, object oRight)
            {
                string sLeft = oLeft as string;
                string sRight = oRight as string;
                int iLeftLength = sLeft.Length;
                int iRightLength = sRight.Length;
                int index = 0;
                while (index < iLeftLength && index < iRightLength)
                {
                    if (sLeft[index] < sRight[index])
                        return -1;
                    else if (sLeft[index] > sRight[index])
                        return 1;
                    else
                        index++;
                }
                return iLeftLength - iRightLength;

            }
        }
        //Verify Signature
        private static int VerifySignature(string sToken, string sTimeStamp, string sNonce, string sMsgEncrypt, string sSigture)
        {
            string hash = "";
            int ret = 0;
            ret = GenarateSinature(sToken, sTimeStamp, sNonce, sMsgEncrypt, ref hash);
            if (ret != 0)
                return ret;
            //System.Console.WriteLine(hash);
            if (hash == sSigture)
                return 0;
            else
            {
                return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_ValidateSignature_Error;
            }
        }

        public static int GenarateSinature(string sToken, string sTimeStamp, string sNonce, string sMsgEncrypt ,ref string sMsgSignature)
        {
            ArrayList AL = new ArrayList();
            AL.Add(sToken);
            AL.Add(sTimeStamp);
            AL.Add(sNonce);
            AL.Add(sMsgEncrypt);
            AL.Sort(new DictionarySort());
            string raw = "";
            for (int i = 0; i < AL.Count; ++i)
            {
                raw += AL[i];
            }

            SHA1 sha;
            ASCIIEncoding enc;
            string hash = "";
            try
            {
                sha = new SHA1CryptoServiceProvider();
                enc = new ASCIIEncoding();
                byte[] dataToHash = enc.GetBytes(raw);
                byte[] dataHashed = sha.ComputeHash(dataToHash);
                hash = BitConverter.ToString(dataHashed).Replace("-", "");
                hash = hash.ToLower();
            }
            catch (Exception)
            {
                return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_ComputeSignature_Error;
            }
            sMsgSignature = hash;
            return 0;
        }
    }
}

Cryptography.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;
using System.Net;
namespace Tencent
{
    class Cryptography
    {
        public static UInt32 HostToNetworkOrder(UInt32 inval)
        {
            UInt32 outval = 0;
            for (int i = 0; i < 4; i++)
                outval = (outval << 8) + ((inval >> (i * 8)) & 255);
            return outval;
        }

        public static Int32 HostToNetworkOrder(Int32 inval)
        {
            Int32 outval = 0;
            for (int i = 0; i < 4; i++)
                outval = (outval << 8) + ((inval >> (i * 8)) & 255);
            return outval;
        }
        /// <summary>
        /// 解密方法
        /// </summary>
        /// <param name="Input">密文</param>
        /// <param name="EncodingAESKey"></param>
        /// <returns></returns>
        /// 
        public static string AES_decrypt(String Input, string EncodingAESKey, ref string appid)
        {
            byte[] Key;
            Key = Convert.FromBase64String(EncodingAESKey + "=");
            byte[] Iv = new byte[16];
            Array.Copy(Key, Iv, 16);
            byte[] btmpMsg = AES_decrypt(Input, Iv, Key);

            int len = BitConverter.ToInt32(btmpMsg, 16);
            len = IPAddress.NetworkToHostOrder(len);


            byte[] bMsg = new byte[len];
            byte[] bAppid = new byte[btmpMsg.Length - 20 - len];
            Array.Copy(btmpMsg, 20, bMsg, 0, len);
            Array.Copy(btmpMsg, 20+len , bAppid, 0, btmpMsg.Length - 20 - len);
            string oriMsg = Encoding.UTF8.GetString(bMsg);
            appid = Encoding.UTF8.GetString(bAppid);

            
            return oriMsg;
        }

        public static String AES_encrypt(String Input, string EncodingAESKey, string appid)
        {
            byte[] Key;
            Key = Convert.FromBase64String(EncodingAESKey + "=");
            byte[] Iv = new byte[16];
            Array.Copy(Key, Iv, 16);
            string Randcode = CreateRandCode(16);
            byte[] bRand = Encoding.UTF8.GetBytes(Randcode);
            byte[] bAppid = Encoding.UTF8.GetBytes(appid);
            byte[] btmpMsg = Encoding.UTF8.GetBytes(Input);
            byte[] bMsgLen = BitConverter.GetBytes(HostToNetworkOrder(btmpMsg.Length));
            byte[] bMsg = new byte[bRand.Length + bMsgLen.Length + bAppid.Length + btmpMsg.Length];

            Array.Copy(bRand, bMsg, bRand.Length);
            Array.Copy(bMsgLen, 0, bMsg, bRand.Length, bMsgLen.Length);
            Array.Copy(btmpMsg, 0, bMsg, bRand.Length + bMsgLen.Length, btmpMsg.Length);
            Array.Copy(bAppid, 0, bMsg, bRand.Length + bMsgLen.Length + btmpMsg.Length, bAppid.Length);
   
            return AES_encrypt(bMsg, Iv, Key);

        }
        private static string CreateRandCode(int codeLen)
        {
            string codeSerial = "2,3,4,5,6,7,a,c,d,e,f,h,i,j,k,m,n,p,r,s,t,A,C,D,E,F,G,H,J,K,M,N,P,Q,R,S,U,V,W,X,Y,Z";
            if (codeLen == 0)
            {
                codeLen = 16;
            }
            string[] arr = codeSerial.Split(',');
            string code = "";
            int randValue = -1;
            Random rand = new Random(unchecked((int)DateTime.Now.Ticks));
            for (int i = 0; i < codeLen; i++)
            {
                randValue = rand.Next(0, arr.Length - 1);
                code += arr[randValue];
            }
            return code;
        }

        private static String AES_encrypt(String Input, byte[] Iv, byte[] Key)
        {
            var aes = new RijndaelManaged();
            //秘钥的大小,以位为单位
            aes.KeySize = 256;
            //支持的块大小
            aes.BlockSize = 128;
            //填充模式
            aes.Padding = PaddingMode.PKCS7;
            aes.Mode = CipherMode.CBC;
            aes.Key = Key;
            aes.IV = Iv;
            var encrypt = aes.CreateEncryptor(aes.Key, aes.IV);
            byte[] xBuff = null;

            using (var ms = new MemoryStream())
            {
                using (var cs = new CryptoStream(ms, encrypt, CryptoStreamMode.Write))
                {
                    byte[] xXml = Encoding.UTF8.GetBytes(Input);
                    cs.Write(xXml, 0, xXml.Length);
                }
                xBuff = ms.ToArray();
            }
            String Output = Convert.ToBase64String(xBuff);
            return Output;
        }

        private static String AES_encrypt(byte[] Input, byte[] Iv, byte[] Key)
        {
            var aes = new RijndaelManaged();
            //秘钥的大小,以位为单位
            aes.KeySize = 256;
            //支持的块大小
            aes.BlockSize = 128;
            //填充模式
            //aes.Padding = PaddingMode.PKCS7;
            aes.Padding = PaddingMode.None;
            aes.Mode = CipherMode.CBC;
            aes.Key = Key;
            aes.IV = Iv;
            var encrypt = aes.CreateEncryptor(aes.Key, aes.IV);
            byte[] xBuff = null;

            #region 自己进行PKCS7补位,用系统自己带的不行
            byte[] msg = new byte[Input.Length + 32 - Input.Length % 32];
            Array.Copy(Input, msg, Input.Length);
            byte[] pad = KCS7Encoder(Input.Length);
            Array.Copy(pad, 0, msg, Input.Length, pad.Length);
            #endregion

            #region 注释的也是一种方法,效果一样
            //ICryptoTransform transform = aes.CreateEncryptor();
            //byte[] xBuff = transform.TransformFinalBlock(msg, 0, msg.Length);
            #endregion

            using (var ms = new MemoryStream())
            {
                using (var cs = new CryptoStream(ms, encrypt, CryptoStreamMode.Write))
                {
                    cs.Write(msg, 0, msg.Length);
                }
                xBuff = ms.ToArray();
            }

            String Output = Convert.ToBase64String(xBuff);
            return Output;
        }

        private static byte[] KCS7Encoder(int text_length)
        {
            int block_size = 32;
            // 计算需要填充的位数
            int amount_to_pad = block_size - (text_length % block_size);
            if (amount_to_pad == 0)
            {
                amount_to_pad = block_size;
            }
            // 获得补位所用的字符
            char pad_chr = chr(amount_to_pad);
            string tmp = "";
            for (int index = 0; index < amount_to_pad; index++)
            {
                tmp += pad_chr;
            }
            return Encoding.UTF8.GetBytes(tmp);
        }
        /**
         * 将数字转化成ASCII码对应的字符,用于对明文进行补码
         * 
         * @param a 需要转化的数字
         * @return 转化得到的字符
         */
        static char chr(int a)
        {

            byte target = (byte)(a & 0xFF);
            return (char)target;
        }
        private static byte[] AES_decrypt(String Input, byte[] Iv, byte[] Key)
        {
            RijndaelManaged aes = new RijndaelManaged();
            aes.KeySize = 256;
            aes.BlockSize = 128;
            aes.Mode = CipherMode.CBC;
            aes.Padding = PaddingMode.None;
            aes.Key = Key;
            aes.IV = Iv;
            var decrypt = aes.CreateDecryptor(aes.Key, aes.IV);
            byte[] xBuff = null;
            using (var ms = new MemoryStream())
            {
                using (var cs = new CryptoStream(ms, decrypt, CryptoStreamMode.Write))
                {
                    byte[] xXml = Convert.FromBase64String(Input);
                    byte[] msg = new byte[xXml.Length + 32 - xXml.Length % 32];
                    Array.Copy(xXml, msg, xXml.Length);
                    cs.Write(xXml, 0, xXml.Length);
                }
                xBuff = decode2(ms.ToArray());
            }
            return xBuff;
        }
        private static byte[] decode2(byte[] decrypted)
        {
            int pad = (int)decrypted[decrypted.Length - 1];
            if (pad < 1 || pad > 32)
            {
                pad = 0;
            }
            byte[] res = new byte[decrypted.Length - pad];
            Array.Copy(decrypted, 0, res, 0, decrypted.Length - pad);
            return res;
        }
    }
}
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