A simple code for Cryptography using C#.net

For doing a simple cryptography we have write a simple code in Windows Form View of Visual Studio.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Cryptografhy

{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        int key;

        //Data And key is Global

        int[] a2 = new int[8] { 0, 0, 0, 0, 0, 0, 0, 0 };
        int[] data = new int[8] { 0, 0, 0, 0, 0, 0, 0, 0 };

        private void button1_Click(object sender, EventArgs e)
        {
            int dno;
            dno = Convert.ToInt16(textBox1.Text);
            key = Convert.ToInt16(textBox2.Text);