C＃SSLStream读取收到的格式错误的消息

Question

我正在使用SSLStream和Socket类在SSL Server Enpoint上工作，遇到的麻烦是，在成功握手之后，我无法解码服务器接收到的消息：

static string  ReadMessage(SslStream sslStream )
{
   byte[] buffer = new byte[2048];
            StringBuilder messageData = new StringBuilder();
            int bytes = -1;
            do
            {
           bytes = sslStream.Read(buffer, 0, buffer.Length);

                // Use Decoder class to convert from bytes to UTF8
                // in case a character spans two buffers.
                Decoder decoder = Encoding.UTF8.GetDecoder();
                char[] chars = new char[decoder.GetCharCount(buffer, 0, bytes)];
                decoder.GetChars(buffer, 0, bytes, chars, 0);
                messageData.Append(chars);
                // Check for EOF.
                if (messageData.ToString().IndexOf("<EOF>") != -1)
                {
                    break;
                }
            } while (bytes != 0);

            return messageData.ToString();
        }

此后，messageData.ToString（）返回：

"��\u0019I�\nbk�imk�(L9�IK\u0004�d;e�(P\r�XTk�((x�&;\u001a�y;s�~k<�(d��q�uO\n�4,\u0005�Om$�\u0011\f#�<!S�Um8�6\u001d<�Om@�WcS�\f<S�W;\u0003�\u0010m\f�"

我是否缺少从SSLStream解密的步骤？