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Text File Encryption Program in C#

This program is designed to encrypt a text file and save the encrypted content into another text file. The encryption method used here is a simple character shifting technique, where each character in the file is shifted by a specified number of positions in the ASCII table. The user can provide the input file name and the shift value, and the program will generate an encrypted version of the file with the same name but with ".enc" appended to the file name.

The program uses basic file reading and writing techniques with StreamReader and StreamWriter to handle the text files. The encryption process involves reading the contents of the input file, applying the encryption to each character, and writing the result to the new file.



Group

File Handling in C#

Objective

1. The program prompts the user for the name of the input file and the shift value for encryption.
2. The content of the input file is read, and each character is encrypted by shifting its ASCII value by the specified number.
3. The encrypted content is written to a new text file with ".enc" appended to the original file name.
4. If the input file does not exist, an error message will be shown.

Create a program to encrypt a text file into another text file.

Example C# Exercise

 Copy C# Code 
using System;
using System.IO;

class TextFileEncryption
{
    // Main method to execute the encryption program
    static void Main(string[] args)
    {
        // Ask the user for the input file name
        Console.WriteLine("Please enter the name of the text file to encrypt:");

        // Read the name of the input file from the user
        string inputFileName = Console.ReadLine();

        // Ask the user for the shift value to use for encryption
        Console.WriteLine("Please enter the shift value for encryption:");
        int shiftValue = int.Parse(Console.ReadLine());

        // Generate the name of the output file by appending ".enc"
        string outputFileName = Path.GetFileNameWithoutExtension(inputFileName) + ".enc" + Path.GetExtension(inputFileName);

        try
        {
            // Open the input file for reading
            using (StreamReader reader = new StreamReader(inputFileName))
            {
                // Open the output file for writing
                using (StreamWriter writer = new StreamWriter(outputFileName))
                {
                    // Read the entire content of the input file
                    string fileContent = reader.ReadToEnd();

                    // Loop through each character in the content and apply encryption
                    foreach (char c in fileContent)
                    {
                        // Encrypt the character by shifting its ASCII value
                        char encryptedChar = (char)(c + shiftValue);

                        // Write the encrypted character to the output file
                        writer.Write(encryptedChar);
                    }

                    // Notify the user that the encryption was successful
                    Console.WriteLine($"The file has been successfully encrypted and saved to {outputFileName}");
                }
            }
        }
        catch (FileNotFoundException)
        {
            // If the file is not found, inform the user
            Console.WriteLine("Error: The specified file could not be found.");
        }
        catch (Exception ex)
        {
            // Handle any other unexpected errors
            Console.WriteLine("An error occurred: " + ex.Message);
        }
    }
}

 Output

//If the input file example.txt contains the following text:
Hello, World!

//And the shift value provided by the user is 3, the output file example.enc will contain the following encrypted text:
Khoor, Zruog!

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