Mallory.cs-Quellcode (CNG-Beispiel)

Aktualisiert: Juli 2008

Das Beispiel für die sichere Kommunikation mit Cryptography Next Generation (CNG) besteht aus drei Konsolenanwendungen: Alice, Bob und Mallory. Die Mallory-Anwendung (Datei Mallory.cs) enthält den folgenden Code.

using System;                           // Required for the IDisposable interface
using System.Text;                      // Required for the Encoding class

public partial class CNG_SecureCommunicationExample
{
    static int  MyColor = 5;                        // Bob White displays white text
    static int  OtherColor = 4;                     // Alice Green displays green text
    static bool fDisplaySendMessage = true;         // Boolean flag controls output display visibility

     static void Main()
        {
        InitConsole("Mallory Purple", 310, 490);
        string s = "";
        while (true)
            {
            SplashScreen();
            s = AppControl("receive", "MalloryControlChannel");
            if ("exit" == s) break;              
            Run();
            }
        }          // End Main


    static void Run()
    {
        ASCIIEncoding enc = new ASCIIEncoding();

        InitializeOptions();

        Display("Hi, I'm Mallory, the man in the middle.\n" +
                "I wonder what Alice and Bob are talking about.\n" +
                "I think I'll listen in.\n\n");

        string AliceChannelName = ReceiveChannelName();
        string BobChannelName   = AliceChannelName + "1";
        SendChannelName(BobChannelName);

//-------------------------------------------------------------------------------------------------


        using (Communicator MalloryAlice = new Communicator("client", AliceChannelName))
        using (Communicator MalloryBob = new Communicator("server", BobChannelName))
            {
            string s;
            fDisplaySendMessage = true;

            if (3 <= Version)
                {
                Display("\nI know Alice will publicaly send Bob a digital signature key.\n");
                byte[] DSKey = MalloryAlice.ChMgr.ReadMessage();                      // Read the message
                MalloryAlice.StoreDSKey(DSKey);
                MalloryBob.StoreDSKey(DSKey);

                s = enc.GetString(DSKey);
                if (fVerbose)
                    {
                    Display("Here it is:\n\n");
                    Display(s + "\n\n", 4);
                    }
                MalloryBob.ChMgr.SendMessage(DSKey);
                }

            if (2 <= Version)
                {
                Display(sep, 1);
                Display("Alice and Bob are going to exchange their\n" +
                        "public cryptographic keys through a public channel.\n" +  // Send and Receive ECDH public keys
                        "First, Alice will send Bob her key.\n\n");

                MalloryAlice.Send_or_Receive_PublicCryptoKey("receive", 4);
                Display("Good.  I just intercepted Alice's public key: \n");
                Display("Next, I will send my MalloryAlice public cryptographic key to Alice:\n\nSending...\n");
                MalloryAlice.Send_or_Receive_PublicCryptoKey("send", 5);

                Display("Next, I will send my MalloryBob public cryptographic key to Bob:\n\nSending...\n");
                MalloryBob.Send_or_Receive_PublicCryptoKey("send", 5);
                Display("Now I will receive Bob's public key: \n");
                if (! MalloryBob.Send_or_Receive_PublicCryptoKey("receive", 2))
                    {                
                    Display("I've been discovered!\n\n",0);
                    System.Threading.Thread.Sleep(3000);
                    return;
                    }
                Display("Good.  I just intercepted Bob's public key: \n");
                }

//-------------------------------------------------------------------------------------------------
// Now that all the keys have been transmitted, have a conversation.

            if (1 < Version)
                {
                Display(sep, 1);
                Display("Now that they have exchanged their keys,\n" +
                       "they can have a secure conversation:\n\n", 5);
                Display(sep, 1);
                }

            Display("From Alice:\n",7);
            OtherColor = 4; 
            s = MalloryAlice.ReceiveMessage();

            Display("To Bob:\n",7); 
            MalloryBob.SendMessage(s,true);

            Display("From Bob:\n",7); 
            OtherColor = 2; 
            s = MalloryBob.ReceiveMessage();

            Display("To Alice:\n",7); 
            MalloryAlice.SendMessage(s,true);

            Display("From Alice:\n",7); 
            OtherColor = 4; 
            string NewSalesContact = MalloryAlice.ReceiveMessage();

            Display("To Bob:\n",7);
            string FakeMessage = "Coho Winery, OneEleven EveryStreet, Chicago"; 
            MalloryBob.SendMessage(FakeMessage,true);

            Display("From Bob:\n",7);
            OtherColor = 2; 
            MalloryBob.ReceiveMessage();

            Display("To Alice:\n",7); 
            MalloryAlice.SendMessage("I think the address is wrong, but I'll keep trying",true);

           // -------------   Gloat   ------------
            if (!fVerbose && Version >= 3)
                Display(sep1, 1);

            Display("\nI am so clever!\n\n" +
                   "Here is what I received: " + NewSalesContact + "\n" +
                   "and here is what I sent: " + FakeMessage + "\n\n" +
                   "They will never catch me!\n\n\n");

            //-------------------------------------------------------------------------------------------------
            if (Version <= 2)
                Display(sep1, 1);

            Display("Perhaps they will talk some more?\n"      +
                   "I'll listen in on what they say\n" +
                   "and add a few extra characters to their messages\n\n");
            Display(sep + sep1,1);
            s = "";

            while (true)
                {
                Display("From Alice:\n",7);
                OtherColor = 4; 
                s = MalloryAlice.ReceiveMessage();
                if ("" == s)
                    {
                    MalloryBob.SendMessage(s,true);
                    break;
                    }

                Display("Send to Bob:\n",7);
                    if (!MalloryBob.SendMessage(s + " qwerty",true))        // If Alice entered CTRL-C, or SYS_CLOSE
                    break;

                Display("From Bob:\n",7);
                OtherColor = 2; 
                s = MalloryBob.ReceiveMessage();

                Display("Send to Alice:\n",7);
                if ("" != s)
                    s += " ytrewq";

                if (!MalloryAlice.SendMessage(s,true))                  // If Alice entered CTRL-C, or SYS_CLOSE
                    break;

                if ("" == s)
                    break;
                }
            }        // End using (Communicator MalloryAlice, Communicator MalloryBob)
//-------------------------------------------------------------------------------------------------
       }       // End Run

}       // public partial class CNG_SecureCommunicationExample

Siehe auch

Aufgaben

Gewusst wie: Erstellen und Ausführen des CNG-Beispiels

Konzepte

Quellcodeübersicht (CNG-Beispiel)

Beispiel für sichere Cryptography Next Generation (CNG)-Kommunikation

Weitere Ressourcen

Kryptografische Dienste

Änderungsprotokoll