using System;

using System.Security.Cryptography;

​

public class Program

{

    public static void Main()

    {

        var aes = new AesCryptoServiceProvider();

        aes.KeySize = 128;

        aes.BlockSize = 128;

        aes.GenerateKey();

        var base64Key = Convert.ToBase64String(aes.Key);

        Console.WriteLine(base64Key);

    }

}