private void richTextBox1_TextChanged(object sender, EventArgs e)
{
var cipher = new ENCaesarCipher();
var message = richTextBox1.Text;
var key = Convert.ToInt32(numericUpDown1.Value);
var encryptedText = cipher.Encrypt(message, key);
richTextBox2.Text = encryptedText;
}
private void button2_Click(object sender, EventArgs e)
{
var cipher = new ENCaesarCipher();
richTextBox1.Text = "";
var key = Convert.ToInt32(numericUpDown1.Value);
var encryptedText = richTextBox2.Text;
var decryptedText = cipher.Decrypt(encryptedText, key);
richTextBox3.Text = decryptedText;
}