Исходный код файла ChannelManager.cs (пример CNG)

В файле ChannelManager.cs содержится исходный код класса ChannelManager, используемого в примере защищенного обмена данными с шифрованием CNG.Этот код выглядит следующим образом.

using System;                           // Required for the IDisposable interface
using System.Text;                      // Required for the Encoding class
using System.IO;                        // Required for the MemoryStream class
using System.IO.Pipes;                  // Required for the NamedPipeClientStream class


public partial class CNG_SecureCommunicationExample
{

// Synchronize session options with the Bob and Mallory applications.
    static string AppControl(string mode, string data)
        {
        if ("send" == mode)
            {
                using (ChannelManager ChMgr = new ChannelManager("server",
                                                     "BobControlChannel"))
                    ChMgr.SendMessage(Encoding.Unicode.GetBytes(data));

                if (fMallory || "exit" == data)
                using (ChannelManager ChMgr = new ChannelManager("server",
                                                     "MalloryControlChannel"))
                    ChMgr.SendMessage(Encoding.Unicode.GetBytes(data));
            }

        else
            {
            using (ChannelManager ChMgr = new ChannelManager("client", data))
                {
                byte[] byteBuffer = ChMgr.ReadMessage();
                string options = Encoding.Unicode.GetString(byteBuffer);
                if ("exit" == options) return "exit"; 
                fVerbose = options.Substring(0,1) == "y"?true:false;
                fMallory = options.Substring(1,1) == "y"?true:false;
                Version  = Int32.Parse(options.Substring(2,1));
                }
            }
        return "";
        }

// Convert the message string into a Unicode byte array.
// Create temporary ChannelManager object.
// Send the new channel name.
// This method demonstrates a bad corporate security policy
//  and allows Mallory to substitute his own new channel name.

    static void SendChannelName(string name)
        {
        byte[] AB_Channel = Encoding.Unicode.GetBytes(name);
        using(ChannelManager ChMgr = new ChannelManager("server", "PublicChannel"))
            ChMgr.SendMessage(AB_Channel);
        }

    static string ReceiveChannelName()
        {
        using (ChannelManager ChMgr = new ChannelManager("client", "PublicChannel"))
            return  Encoding.Unicode.GetString(ChMgr.ReadMessage());
        }


// Pipe server or client class 
   internal sealed class ChannelManager  : IDisposable
        {
        NamedPipeServerStream m_ServerPipe;
        NamedPipeClientStream m_ClientPipe;
        Stream m_Stream;

        string m_ChannelType;                   // "client" or "server"
        string m_ChannelName;
        byte[] byteBuffer = new byte[1000];     // Only big enough for small messages

        public ChannelManager(string ChannelType, string ChannelName)
            {
            m_ChannelType = ChannelType;
            m_ChannelName = ChannelName;

            if ("server" == ChannelType)
                {
                m_ServerPipe = new NamedPipeServerStream(ChannelName,
                        PipeDirection.InOut, 1,
                        PipeTransmissionMode.Message);
                m_Stream = m_ServerPipe;
                m_ServerPipe.WaitForConnection();                
            }
            else 
                {
                m_ClientPipe = new NamedPipeClientStream(ChannelName);
                m_Stream = m_ClientPipe;
                m_ClientPipe.Connect(); 
                m_ClientPipe.ReadMode = PipeTransmissionMode.Message;    
                }
            }

        public void Dispose()
            {
            if (m_Stream != null)
               (m_Stream as IDisposable).Dispose();
            }

        public byte[] ReadMessage()
            {
            MemoryStream ms = new MemoryStream();
            int count;

            do {
               count = m_Stream.Read(byteBuffer, 0 , byteBuffer.Length);
               if (count > 0 )
                   ms.Write(byteBuffer, 0 ,count);
               } while (count == byteBuffer.Length);
            byte[] bA = ms.ToArray();
            return bA;
            }

        public bool SendMessage(byte[] msg)
            {
            try
                {
                m_Stream.Write(msg, 0, msg.Length);
                }
            catch (IOException e)
                {
                Display("Connection has been closed.\n" + e +"\n", MyColor);
                return false;
                }
            return true;
            }
        }   // End class ChannelManager

}       // End ChannelManager.cs: public partial class CNG_SecureCommunicationExample

См. также

Задачи

Практическое руководство. Построение и запуск примера CNG

Основные понятия

Общие сведения об исходном коде (пример CNG)

Пример защищенного обмена данными с шифрованием CNG

Службы криптографии