Mallory.cs-Quellcode (CNG-Beispiel)
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);
Console.WriteLine("Press the enter key to continue.");
Console.ReadLine();
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