C#基础代码片段： private static byte[] AES_decrypt(string input, string iv, string key)         {             RijndaelManaged aes = new RijndaelManaged();             aes.KeySize = 256;             aes.BlockSize = 128;             aes.Mode = CipherMode.CBC;             aes.Padding =  PaddingMode.PKCS7;             aes.Key = Convert.FromBase64String(key);             aes.IV = Convert.FromBase64String(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;         } 错误日志： ExecptionMessage:Padding is invalid and cannot be removed. mscorlib    at System.Security.Cryptography.RijndaelManagedTransform.DecryptData(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount, Byte[]& outputBuffer, Int32 outputOffset, PaddingMode paddingMode, Boolean fLast)    at System.Security.Cryptography.RijndaelManagedTransform.TransformFinalBlock(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount)    at System.Security.Cryptography.CryptoStream.FlushFinalBlock()    at System.Security.Cryptography.CryptoStream.Dispose(Boolean disposing)    at System.IO.Stream.Close()    at System.IO.Stream.Dispose()    at Senparc.Weixin.WxOpen.Helpers.EncryptHelper.AES_Decrypt(String Input, Byte[] Iv, Byte[] Key)    at Senparc.Weixin.WxOpen.Helpers.EncryptHelper.DecodeEncryptedData(String sessionKey, String encryptedData, String iv) 加密数据： sessionKey:98195476102492321891401391061935624977242；IV:116115241129461711788323441202601974169239； encryptedData:deWfUALVVTxrux2cp0qeqLWotTHTIpRmIrpcuWoh3ngyr7vjCDYq1wh2Q0CE6Zj9P/V2ZVqtjkVAiGdBuBR8fSs9qpWhb9ieO5FoumuvgoM6HP5+7Eul6lm8njXJlbTZr+pODAIeMoBIwpQUPpCLwYtpSuKlQGKvsrmoVU5j5xgoKm4dyKmNwq3qcqE5Q+HUOV0r/c7GusFWZD0haaccduMjmKAyupCpbwdDu6kiVfEo1pVZdp5j4C5ihrZdE7gzeS9vOAFDaB+NXPB6Lz+H8js6BH8gVJ7tZ1KUAwqt+FIqHHBKsREKoyjePwREkRc1Sr/N+QR1vps2cFGpqp16NAoTyT/JFi2jNs8PgrrEYZkjVvyMUYFlDnq5BWNyyh5RX34JEq7EN62sc+wfAMB2Nrm/QEcBCtYLycP3xcQnCLasU2SQbpIr5GOUz7aiIu5rwMXMUDDg7jxCOA4+ORfSHUgS6OczRjY+QqrcfKmlA84=