If Not String.IsNullOrEmpty(TextBox1.Text) And Not String.IsNullOrEmpty(TextBox2.Text) Then

        Dim password = TextBox1.Text
        Dim key = TextBox2.Text

        Dim keyGenerator = New Rfc2898DeriveBytes(key, 8)
        Dim r = New RijndaelManaged

        r.Mode = CipherMode.CBC
        r.Padding = PaddingMode.Zeros
        r.BlockSize = 256
        r.KeySize = 256
        r.FeedbackSize = 256

        r.IV = keyGenerator.GetBytes(CType(r.BlockSize / 8, Integer))
        r.Key = keyGenerator.GetBytes(CType(r.KeySize / 8, Integer))

        Dim transform As ICryptoTransform = r.CreateEncryptor()

        Dim encoded As Byte() = Encoding.ASCII.GetBytes(password)
        Dim target As Byte() = transform.TransformFinalBlock(encoded, 0, encoded.Length)

        TextBox3.Text = Encoding.ASCII.GetString(target)

    End If