How can I use cryptography in C#?

How can I use cryptography in C#?

You can use the System.Security.Cryptography namespace in C#. It provides classes for various cryptographic operations.

Can you give me an example of encrypting a string?

Sure! Here's a simple example using AES encryption:

using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

public class AesExample
{
    public static void Main()
    {
        string original = "Hello, World!";
        using (Aes aes = Aes.Create())
        {
            aes.Key = Encoding.UTF8.GetBytes("your-32-byte-key-here");
            aes.IV = Encoding.UTF8.GetBytes("your-16-byte-iv");

            // Encrypt
            ICryptoTransform encryptor = aes.CreateEncryptor(aes.Key, aes.IV);
            using (MemoryStream msEncrypt = new MemoryStream())
            {
                using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                {
                    using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                    {
                        swEncrypt.Write(original);
                    }
                    byte[] encrypted = msEncrypt.ToArray();
                    Console.WriteLine(Convert.ToBase64String(encrypted));
                }
            }
        }
    }
}

What about decrypting the string?

To decrypt the string, you can use a similar approach with the CreateDecryptor method. Here's an example:

// Decrypt
ICryptoTransform decryptor = aes.CreateDecryptor(aes.Key, aes.IV);
using (MemoryStream msDecrypt = new MemoryStream(encryptedBytes))
{
    using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
    {
        using (StreamReader srDecrypt = new StreamReader(csDecrypt))
        {
            string decrypted = srDecrypt.ReadToEnd();
            Console.WriteLine(decrypted);
        }
    }
}