' Write base64 encoded file
        Dim sout As New FileStream("C:\test.txt", FileMode.OpenOrCreate, _
          FileAccess.Write, FileShare.None)
        Dim csout As New CryptoStream(sout, New ToBase64Transform(), _
        CryptoStreamMode.Write)
        Dim sw As New StreamWriter(csout)
        sw.WriteLine("some data line 1")
        sw.WriteLine("some data line 2")
        sw.Write("some data line 3")
        sw.Close()
 
        ' Read base64 encoded file
        Dim sin As New FileStream("C:\test.txt", FileMode.Open, _
          FileAccess.Read, FileShare.Read)
        Dim sr As New StreamReader(sin)
        RichTextBox1.Text = sr.ReadToEnd()
        sr.Close()
 
        ' Read and decode base64 encoded file
        sin = New FileStream("C:\test.txt", FileMode.Open, FileAccess.Read, _
          FileShare.Read)
        Dim csin As New CryptoStream(sin, New FromBase64Transform, _
        CryptoStreamMode.Read)
        sr = New StreamReader(csin)
        RichTextBox2.Text = sr.ReadToEnd()
        sr.Close()