Book chapter as revised selected paper presented at the 9th International Conference, CRITIS 2014, Limassol, Cyprus, October 13-15, 2014, in Critical Information Infrastructures Security, Volume 8985 of the series Lecture Notes in Computer Science, pp 37-42, edited by Springer International Publishing, 25 March 2016, DOI 10.1007/978-3-319-31664-2_5