C#微信公众号开发系列教程三(消息体签名及加解密)
http://www.cnblogs.com/zskbll/p/4139039.html
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C#微信公眾號開發系列教程一(調試環境部署)
C#微信公眾號開發系列教程一(調試環境部署續:vs遠程調試)
C#微信公眾號開發系列教程二(新手接入指南)
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?? 距離上一篇博文已經半個月了,本來打算每兩天更新一次的,但可憐苦逼碼農無日無夜的加班。第一篇博文發表后,博文視點的編輯就找到我,問我想不想出版這個系列,我當時瞬間就想到了王大錘的獨白,想想真的是有點小激動,后面按照那邊的要求,提交了申請書,也提交了目錄,可惜文筆不行,再加上最近太忙,樣稿一直沒有給他,感覺挺愧疚了。真心希望能幫一下迷茫的新手開發者,希望各位在看博文的時候能給小弟一些建議或意見,讓這個系列能更完美的面向大家。
?? 前幾篇主要是微信開發的準備工作,也沒有什么技術含量。在第一篇和第二篇中,我主要講的是使用花生殼來配合vs進行代碼調試,也一度被園友吐槽本人是花生殼請來的逗比,沒辦法,為了和花生殼劃清界限,在本篇進入正文前,為大家介紹一個比花生殼更好用的工具ngrok(群里的朋友介紹的,我現在冒充下逗比介紹給大家。),ngrok的好處我就不在此具體說明了,畢竟不是本文的重點,我錄了視頻,有興趣的可以下載看下。鏈接:http://pan.baidu.com/s/1eQ8akQQ?密碼: ov6l
?? 出于安全考慮,微信公眾平臺在10月份的時候加入了消息體的加解密功能,首先,需要先驗證簽名,用于公眾平臺和公眾賬號驗證消息體的正確性,其次,針對推送給公眾號的普通消息和事件消息,以及推送給設備公眾賬號的設備進行加密,最后,公眾號對密文消息的回復也需要加密。啟用加解密功能后,公眾平臺服務器在向公眾號服務器配置地址推送消息時,url將新增加兩個參數,一個是加密類型一個是消息體簽名,并以此來體現新功能。加密算法采用AES。關于明文模式,兼容模式,安全模式的說明,大家請參考官方文檔.
驗證消息真實性和加解密的幫助類官方提供的有demo,再次不詳細講述了,下載下來可以直接調用,下面請看代碼:
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Security.Cryptography; using System.IO; using System.Net; namespace WxApi {public 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();//秘鑰的大小,以位為單位aes.KeySize = 256;//支持的塊大小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();//秘鑰的大小,以位為單位aes.KeySize = 256;//支持的塊大小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 自己進行PKCS7補位,用系統自己帶的不行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 注釋的也是一種方法,效果一樣//ICryptoTransform transform = aes.CreateEncryptor();//byte[] xBuff = transform.TransformFinalBlock(msg, 0, msg.Length);#endregionusing (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;// 計算需要填充的位數int amount_to_pad = block_size - (text_length % block_size);if (amount_to_pad == 0){amount_to_pad = block_size;}// 獲得補位所用的字符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);}/*** 將數字轉化成ASCII碼對應的字符,用于對明文進行補碼* * @param a 需要轉化的數字* @return 轉化得到的字符*/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;}} } 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 : 簽名驗證錯誤 //-40002 : xml解析失敗 //-40003 : sha加密生成簽名失敗 //-40004 : AESKey 非法 //-40005 : appid 校驗錯誤 //-40006 : AES 加密失敗 //-40007 : AES 解密失敗 //-40008 : 解密后得到的buffer非法 //-40009 : base64加密異常 //-40010 : base64解密異常 namespace WxApi {public class MsgCrypt{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};//構造函數// @param sToken: 公眾平臺上,開發者設置的Token// @param sEncodingAESKey: 公眾平臺上,開發者設置的EncodingAESKey// @param sAppID: 公眾帳號的appidpublic MsgCrypt(string sToken, string sEncodingAESKey, string sAppID){m_sToken = sToken;m_sAppID = sAppID;m_sEncodingAESKey = sEncodingAESKey;}// 檢驗消息的真實性,并且獲取解密后的明文// @param sMsgSignature: 簽名串,對應URL參數的msg_signature// @param sTimeStamp: 時間戳,對應URL參數的timestamp// @param sNonce: 隨機串,對應URL參數的nonce// @param sPostData: 密文,對應POST請求的數據// @param sMsg: 解密后的原文,當return返回0時有效// @return: 成功0,失敗返回對應的錯誤碼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 signatureint ret = 0;ret = VerifySignature(m_sToken, sTimeStamp, sNonce, sEncryptMsg, sMsgSignature);if (ret != 0)return ret;//decryptstring 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;}//將企業號回復用戶的消息加密打包// @param sReplyMsg: 企業號待回復用戶的消息,xml格式的字符串// @param sTimeStamp: 時間戳,可以自己生成,也可以用URL參數的timestamp// @param sNonce: 隨機串,可以自己生成,也可以用URL參數的nonce// @param sEncryptMsg: 加密后的可以直接回復用戶的密文,包括msg_signature, timestamp, nonce, encrypt的xml格式的字符串,// 當return返回0時有效// return:成功0,失敗返回對應的錯誤碼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;elseindex++;}return iLeftLength - iRightLength;}}//Verify Signatureprivate 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;}} }?
在處理程序中,首先獲取到公眾平臺服務器發送過來的數據,并轉成字符串。代碼如下
string postStr = "";Stream s = VqiRequest.GetInputStream();//此方法是對System.Web.HttpContext.Current.Request.InputStream的封裝,可直接代碼byte[] b = new byte[s.Length];s.Read(b, 0, (int)s.Length);postStr = Encoding.UTF8.GetString(b);然后再分別獲取url中的參數:timestamp,nonce,msg_signature,encrypt_type。可以看到,在明文模式下是沒有encrypt_type參數的。如圖:
明文模式
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兼容模式和安全模式
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兼容模式和安全模式則加入了消息體的簽名與加密類型兩個參數。
由于在實際的運營中,兼容模式不太可能使用,所以在此不做詳細介紹了。
接著上面的講。獲取到url中的參數后,判斷encrypt_type的值是否為aes,如果是則說明是使用的兼容模式或安全模式,此時則需調用解密相關的方法進行解密。
if (encrypt_type == "aes"){requestXML.IsAes = true;requestXML.EncodingAESKey = aeskey;requestXML.token = token;requestXML.appid = appid;var ret = new MsgCrypt(token, aeskey, appid);int r = ret.DecryptMsg(msg_signature, timestamp, nonce, postStr, ref data);if (r!=0){WxApi.Base.WriteBug("消息解密失敗");return null;}}否則則直接解析接收到的xml字符串。
下圖是接收到的密文:
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解密之后的內容如下:
此時就可以解析此xml了。
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當需要回復加密的請求時,回復的內容也是需要加密的,所以在回復前需要判斷此條接收到的消息是否加密,如果是加密的,則需要將需要回復的內容加密后,再進行回復。回復消息的方法將在下一篇中具體講解,此篇只講解加密的過程。
處理代碼如下:
private static void Response(WeiXinRequest requestXML, string data){if (requestXML.IsAes){var wxcpt = new MsgCrypt(requestXML.token, requestXML.EncodingAESKey, requestXML.appid);wxcpt.EncryptMsg(data, Utils.ConvertDateTimeInt(DateTime.Now).ToString(), Utils.GetRamCode(), ref data);}Utils.ResponseWrite(data);}將接收到的消息實體和需要回復的內容xml傳遞過來,如果是加密的,則加密后再Response,否則直接Response。
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時間倉促,如有不明白的,請留言,如果你覺得本篇博文對你有幫助,請點擊一下推薦,推薦給更多的朋友的。
各位有建議或者意見可留言給我哦,或者加如QQ群一起進行交流。
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如果你是土豪,可以掃描下面的二維碼懸賞一下,你的支持是筆者繼續更新下去的動力。
總結
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