' Encrypt using stream (binary)
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button3.Click
        Dim rd As New RijndaelManaged()
 
        Dim md5 As New MD5CryptoServiceProvider()
        Dim key() As Byte = md5.ComputeHash(Encoding.UTF8.GetBytes( _
          TextBox2.Text))
        md5.Clear()
        rd.Key = key
        rd.GenerateIV()
        Dim iv() As Byte = rd.IV
 
        Dim ms As New MemoryStream()
 
        ms.Write(iv, 0, iv.Length)
 
        Dim cs As New CryptoStream(ms, rd.CreateEncryptor, _
          CryptoStreamMode.Write)
        Dim data() As Byte = System.Text.Encoding.UTF8.GetBytes(TextBox1.Text)
 
        cs.Write(data, 0, data.Length)
        cs.FlushFinalBlock()
 
        Dim encdata() As Byte = ms.ToArray()
        TextBox3.Text = Convert.ToBase64String(encdata)
        cs.Close()
        rd.Clear()
        TextBox1.Text = ""
    End Sub
 
    ' Decrypt using stream (binary)
    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button4.Click
        Dim rd As New RijndaelManaged()
 
        Dim md5 As New MD5CryptoServiceProvider()
        Dim key() As Byte = md5.ComputeHash(Encoding.UTF8.GetBytes( _
          TextBox2.Text))
        md5.Clear()
 
        Dim encdata() As Byte = Convert.FromBase64String(TextBox3.Text)
        Dim ms As New MemoryStream(encdata)
        Dim iv(15) As Byte
        ms.Read(iv, 0, rijndaelIvLength)
        rd.IV = iv
        rd.Key = key
 
        Dim cs As New CryptoStream(ms, rd.CreateDecryptor, _
          CryptoStreamMode.Read)
 
        Dim data(ms.Length - rijndaelIvLength - 1) As Byte
        Dim i As Integer = cs.Read(data, 0, data.Length)
 
        TextBox1.Text = System.Text.Encoding.UTF8.GetString(data, 0, i)
        cs.Close()
        rd.Clear()
    End Sub