Dim fs As FileStream = File.OpenRead("C:\WXHOEM_DE.ISO")
        Dim sha1 As New SHA1Managed()
        Dim cs As New CryptoStream(fs, sha1, CryptoStreamMode.Read)
        Dim br As New BinaryReader(cs)
        Dim iread As Integer
        Dim buf(1024 * 1024) As Byte
        While True
            iread = br.Read(buf, 0, buf.Length)
            If iread = 0 Then
                Exit While
            End If
            ' Arbeiten...
        End While
        br.Close()
        sha1.Clear()