1. Horst Görtz Institute for IT-Security, Ruhr University Bochum, Bochum, Germany
2. UMR 6285, Lab-STICC, Univ. Bretagne-Sud, Lorient, France
3. UMR 6285, Lab-STICC, ENSTA Bretagne, Brest, France
4. Ruhr University Bochum, Bochum, Germany
5. DFKI GmbH, Bremen, Germany