Utilities.cs fonte Code (CNG exemplo)

O arquivo Utilities.cs fornece os métodos de utilitário usados pelo exemplo de comunicação segura a CNG (Cryptography Next Generation).Ele contém o código a seguir.

using System;                           // IDisposable interface
using System.Diagnostics;               // Process control               
using System.Runtime.InteropServices;   // MoveWindow, GetConsoleWindow Win32 APIs

public partial class CNG_SecureCommunicationExample
    {
    static string sep = "------------------------------------" +
                        "------------------------------------",
                  sep1 = sep + "\n", sep2 = "\n" + sep1;

    static string MyName;

                                  // Application control flags
    static int  Version = 0;      // 1 - Plaintext, 2 - Encryption, 3 - Signing
                                  // 4 - Private digital signature, 5 - Termination
    static bool fVerbose;         // Display encrypted output           
    static bool fMallory;         // Disable Mallory


    [DllImport("user32.dll")]
    public static extern bool MoveWindow(IntPtr hwnd, int x, int y,
                                  int nWidth, int nHeight, bool bRepaint);
    [DllImport("kernel32.dll")]
    public static extern IntPtr GetConsoleWindow();


// Run the Bob and Mallory executable.
// If Alice.exe is a standalone process, it is not being run from
// the Visual Studio debugger; therefore, it must programatically 
// run Bob and Mallory.
    static bool Autoloader()
        {
        Process [] AliceProcess = Process.GetProcessesByName("Alice");
        if (AliceProcess.Length > 0)
            {
            try {
                Process.Start("bob.exe");                 
                Process.Start("mallory.exe");             
                }

            catch(Exception e)
                {
                Display("\nFailure loading Bob.exe or Mallory.exe:\n"
                       + e.Message + "\n",1);
                return false;
                }
            }
            return true;
        }

// Set console size, position, title
    static void InitConsole(string name, int left, int top)
        {
        Console.Clear();
        IntPtr hwnd = GetConsoleWindow();
        MoveWindow(hwnd, left, top, 600, 500, true);
        Console.SetBufferSize(72, 500);
        MyName = name;
        SplashScreen();
        }

// Provide titling services
    static void SplashScreen()
        {
        Console.Clear();
        Display("       Cryptography Next Generation " +
                "Secure Communication Example\n\n" + sep);
        Console.Title = "Hi, I'm " + MyName + "!";
        }

// Prompt user for input.
// fBlankOkay = true if blank lines are acceptable
  static string ReadALine(bool fBlankOkay)
        {
        while (true)
            {
            Display(":> ", 1);
            Display("", 3);
            string s = Console.ReadLine();
            if (fBlankOkay)
                return s;
            if ("" != s)
                return s;
            }
        }

// Read until a character from list is entered.
// Do not accept a blank.
    static string ReadAChar(string options)
        {
        while(true)
            {
            string s = ReadALine(false);        // No blanks allowed.
            if (options.Contains(s))
                return s;
            }
        }

// Display session options, prompt for input
    static string InitializeOptions()
        {
        string s;
        if ("Alice Green" == MyName)
            {

            Display("Please select a security model:\n\n" +
                    "1 = Plaintext only\n" +
                    "2 = Encrypt messages\n" +
                    "3 = Encrypt messages, use public key to digitally sign messages.\n" +
                    "4 = Encrypt messages, use private key to digitally sign messages.\n" +
                    "5 = Encrypt messages, use private key to digitally sign messages\n" +
                    "    and cryptographic keys. Terminate on all security failures.\n" +
                    "x = Exit\n\n", 1);

            s = ReadAChar("12345x");
            if ("x" == s) return "exit";

            Version = Int32.Parse(s);

            Display("Include Mallory? Y/N\n", 1);
            fMallory = "y" == ReadAChar("ynYN") ?  true : false;              

            if (Version != 1)
                {
                Display("Verbose output mode? Y/N\n", 1);
                fVerbose = "y" == ReadAChar("ynYN") ? true : false;               
                } 
            }
        Console.Clear();
        Console.Title = "Hi, I'm " + MyName + "!";

        Console.Title += "   Security Version " + Version;

        Display("       Cryptography Next Generation Secure Communication Example\n\n" +
                "Security Version: " + Version +
                "   Mode: " + (fVerbose ? "Verbose" : "Regular") +
                "   Mallory: " + (fMallory ? "Yes":"No") + 
                "   Signatures: " + (Version >= 3? "Yes":"No"));

        Display(sep2, 1);   

        return (fVerbose ? "y" : "n") + (fMallory ? "y" : "n") + Version;
        }

// Calls 
    static void Display(string s)
        {
            Display(s, MyColor);
        }


/////////////////////////////////////////////////////////////////////////////////////////
// NAME         Display:     Ouput function that wraps Console.Write calls and
//                           colors the output message.
//
// PARAMETERS:  string DisplayString:   Output message.
//              int color:              Output message color.  If no color, use yellow.
//
//              COLOR       USE                   DESCRIPTION
//              ------------------------------------------------------------------------
//              0 Red       Security failures     Error message displayed to the user
//              1 Yellow    Default color         Options menu and application messages
//              2 White     Bob's color           Messages from Bob White
//              3 Cyan      User's color          User input
//              4 Green     Alice's color         Messages from Alice Green
//              5 Majenta   Mallory's color       Messages from Mallory Purple
//              6 Yellow    Default color         Application Restart prompt
//              7 Gray      Encrypted data        
//
// RETURN:      string:     "r":    rerun the application
//                          "exit": close the application
//
// OPERATION:   1.  Set ConsoleColor to color. If color is not specified,
//                  the default yellow color is set.  
//              2.  Write the DisplayString in the requested color.
//              3.  Process Continue functionality if color = 6.
//                  Display("", 6) will generate a prompt, and query the user
//                  to continue the application.
//
/////////////////////////////////////////////////////////////////////////////////////////

    static void Display(string DisplayString, int color)
        {
        ConsoleColor[] cc = { ConsoleColor.Red, ConsoleColor.Yellow,
                              ConsoleColor.White, ConsoleColor.Cyan,
                              ConsoleColor.Green, ConsoleColor.Magenta,
                              ConsoleColor.Yellow,ConsoleColor.Gray
                            };
        Console.ForegroundColor = cc[color];
        Console.Write(DisplayString);

        if (6 == color)
            {
            Console.WriteLine(sep + sep +
                  "Press the enter key to continue\n\n");
            Console.ReadLine();
            }
        }

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

Consulte também

Tarefas

Como: compilação e executar o exemplo CNG

Conceitos

Visão geral do código fonte (CNG exemplo)

Exemplo da Secure Communication Cryptography Next Generation (CNG)

Outros recursos

Serviços de criptografia

Date

History

Motivo

Julho de 2008

Tópico adicional.

Aprimoramento de informações.