Programa Para 'Cifrar-Descifrar' Archivos De Imagen BMP En C#

using System;
using System.IO;

class BMPEncryptDecrypt
{
    // Main method where the program starts execution
    static void Main(string[] args)
    {
        // Check if the user provided the correct number of arguments
        if (args.Length != 1)
        {
            Console.WriteLine("Usage: encryptDecrypt ");
            return;
        }

        // Get the input BMP file name from the arguments
        string fileName = args[0];

        // Check if the specified file exists
        if (!File.Exists(fileName))
        {
            Console.WriteLine("The specified file does not exist.");
            return;
        }

        try
        {
            // Open the file with FileStream for both reading and writing
            using (FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.ReadWrite))
            {
                // Read the first two bytes of the file to check the "BM" marker
                byte[] buffer = new byte[2];
                fs.Read(buffer, 0, 2);

                // Check if the first two bytes are "BM" or "MB"
                if (buffer[0] == 'B' && buffer[1] == 'M')
                {
                    // If it's "BM", change it to "MB" (encryption)
                    Console.WriteLine("Encrypting file...");

                    // Move the file pointer back to the start of the file
                    fs.Seek(0, SeekOrigin.Begin);

                    // Write "MB" instead of "BM"
                    fs.WriteByte((byte)'M'); // Write 'M'
                    fs.WriteByte((byte)'B'); // Write 'B'

                    Console.WriteLine("File encrypted successfully.");
                }
                else if (buffer[0] == 'M' && buffer[1] == 'B')
                {
                    // If it's "MB", change it to "BM" (decryption)
                    Console.WriteLine("Decrypting file...");

                    // Move the file pointer back to the start of the file
                    fs.Seek(0, SeekOrigin.Begin);

                    // Write "BM" instead of "MB"
                    fs.WriteByte((byte)'B'); // Write 'B'
                    fs.WriteByte((byte)'M'); // Write 'M'

                    Console.WriteLine("File decrypted successfully.");
                }
                else
                {
                    // If the first two bytes are not "BM" or "MB", print an error
                    Console.WriteLine("The file does not have the expected 'BM' or 'MB' marker.");
                }
            }
        }
        catch (Exception ex)
        {
            // Handle any exceptions that may occur during file processing
            Console.WriteLine("An error occurred: " + ex.Message);
        }
    }
}

 Output

//For example, if you run the program on a BMP file named myImage.bmp:

//When encrypting (changing "BM" to "MB"):
Encrypting file...
File encrypted successfully.

//When decrypting (changing "MB" back to "BM"):
Decrypting file...
File decrypted successfully.