Information Security Theory and Practice. Security, Privacy and Trust in Computing Systems and Ambient Intelligent Ecosystems [electronic resource] : 6th IFIP WG 11.2 International Workshop, WISTP 2012, Egham, UK, June 20-22, 2012. Proceedings / edited by Ioannis Askoxylakis, Henrich C. Pöhls, Joachim Posegga.