C# Aes CryptoStream Specified padding mode is not valid for this algorithm的解決方法

//解密數據
            using (var ss = File.OpenRead(@"d:\qq.d.flac"))
            {
                using (FileStream w = new FileStream(@"d:\qq.flac", FileMode.Create))
                {
                    using (var cs = AesStream.StreamDecrypt(w, "qq"))
                    {
                        ss.Seek(0, SeekOrigin.Begin);
                        for (int i = 0; i < ss.Length; i += 4096)
                        {
                            byte[] chunkData = new byte[4096];
                            int bytesRead = 0;

　　　　　　　　        //Updates the underlying data source or repository with the current state of the buffer, then clears the buffer.
                            if (!cs.HasFlushedFinalBlock)
                            {
                                cs.FlushFinalBlock();
                            }
                            bytesRead = ss.Read(chunkData, 0, chunkData.Length);

if (i > 4096*1024)
                            {
                                break;
                            }
                            cs.Write(chunkData, 0, bytesRead);
                        }
                    }
                }
            }