Public Function EnCrypt(ByVal Text As String,ByVal Passwort As String) As _
      String
    	    Dim rd As New RijndaelManaged
    	    Dim md5 As New MD5CryptoServiceProvider
    	    Dim key() As Byte = md5.ComputeHash(Encoding.UTF8.GetBytes(Passwort))
    	    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 = Encoding.UTF8.GetBytes(Text)
    	    cs.Write(data,0,data.Length)
    	    cs.FlushFinalBlock()
    	    Dim encdata() As Byte = ms.ToArray()
    	    cs.Close()
    	    rd.Clear()
    	    Return(Convert.ToBase64String(encdata))
    	End Function

    	Public Function DeCrypt(ByVal Text As String,ByVal Passwort As String) As _
      String
    	    Dim rd As New RijndaelManaged
    	    Dim rijndaelIvLength As Integer = 16
    	    Dim md5 As New MD5CryptoServiceProvider
    	    Dim key() As Byte = md5.ComputeHash(Encoding.UTF8.GetBytes(Passwort))
    	    md5.Clear()
    	    Dim encdata() As Byte = Convert.FromBase64String(Text.Trim())
    	    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) As Byte
    	    Dim i As Integer = cs.Read(data,0,data.Length)
    	    cs.Close()
    	    rd.Clear()
    	    Return(Encoding.UTF8.GetString(data,0,i))
    	End Function

Dim ContMenList As String = ...  ' Datei auslesen und in eine Variable 
' speichern. Z. b. ContMenList
 
Dim Einträge As String = DeCrypt(ContMenList,"dein passwort hier hin")
 
 ' Die Ausführenden Befehle und Änderungen mit dem jetzt sichtbaren text.
 
ContMenList = EnCrypt(Einträge,"dein passwort hier hin")
 
 '  Wieder in die Datei reinschreiben