Dim data(ms.Length - rijndaelIvLength) As Byte

    Public Function Verschlüsseln(ByVal data As Byte) As Byte
        Dim rd As New RijndaelManaged
        Dim md5 As New MD5CryptoServiceProvider
        Dim key() As Byte = md5.ComputeHash(Encoding.UTF8.GetBytes("geheim"))
        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)
        cs.WriteByte(data)
        cs.FlushFinalBlock()
        Dim encdata As Byte = ms.ToArray(0)
        Verschlüsseln = encdata
        cs.Close()
        rd.Clear()
    End Function
 
    Public Function Entschlüsseln(ByVal cryptdata As Byte) As Byte
        Dim rd As New RijndaelManaged
        Dim md5 As New MD5CryptoServiceProvider
        Dim key() As Byte = md5.ComputeHash(Encoding.UTF8.GetBytes("geheim"))
        md5.Clear()
        Dim dataArray(0) As Byte
        dataArray(0) = cryptdata
        Dim ms As New MemoryStream(dataArray)
        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)
        Entschlüsseln = data(0)
        cs.Close()
        rd.Clear()
    End Function

N I C H T S - I S T - S O - W I E - E S - S C H E I N T