PhD Seminar Course on

State-Based Notions of Opacity in Security Applications of Discrete Event Systems

Cagliari, June 19, 2012



This activity was made possible by the "Visiting Professors 2011" program of the University of Cagliari, sponsored by the Autonomous Region of Sardinia

Instructor: Prof. Christoforos Hadjicostis
University of Cyprus
Duration: 2 hours
Schedule: Tuesday June 19, 2012 - h: 18:00
Venue: B1 room (DIEE, Stand B)
Topics: This talk discusses how state-based notions of opacity can be used to capture security and privacy considerations in emerging applications of discrete event systems. More specifically, we consider systems that are described by (nondeterministic) finite automata and assume that a passive intruder observes system activity through some projection map and uses knowledge of the system model in order to make inferences about the possible state of the system. We assume that there exists a set of states S that is considered secret, and we introduce and analyze various state-based notions of opacity with respect to this set of secret states: (i) current-state opacity, (ii) initial-state opacity, (iii) K-step opacity, and (iv) infinite-step opacity. The talk discusses methods to verify these state-based notions of opacity using various types of state estimators, and also illustrates via examples how such notions can be used to characterize the security requirements in many applications of interest, including encryption using pseudo-random generators, coverage of mobile agents in sensor networks, and anonymity requirements in protocols for web transactions.
Organizer: Carla Seatzu
Dep. of Electrical and Electronic Engineering
University of Cagliari, Italy
Email: seatzu@diee.unica.it