using System;

using System.IO;

using System.Text;

using System.Security.Cryptography;

public class Program

{

    public static void Main()

    {

        using var crypt = Aes.Create();

        crypt.Mode = CipherMode.CBC;

        crypt.KeySize = 256;

        crypt.GenerateIV();

        crypt.GenerateKey();

        using var stream = new MemoryStream();

        using var cstream = new CryptoStream(stream, crypt.CreateEncryptor(), CryptoStreamMode.Write);

        var content = Encoding.ASCII.GetBytes("1234567890ABCDEF1");

        cstream.Write(content, 0, content.Length);

        cstream.FlushFinalBlock();

        var plainTextLength = content.Length;

        var estimated = (plainTextLength/16 + 1) * 16;

        Console.WriteLine("Plain:");

        Console.WriteLine("Bytes: " + BitConverter.ToString(content));

        Console.WriteLine("Length:" + plainTextLength);

        Console.WriteLine("Cipher:");

        Console.WriteLine("Estimated length: " + estimated);

        Console.WriteLine("Real length: " + stream.Length);

        Console.WriteLine("Bytes: " + BitConverter.ToString(stream.ToArray()));

​

    }

}