On Zero-sum Stochastic Game Models of Security in Controlled Systems

Cedric Langbort
Associate Professor, Aerospace Engineering, UIUC
Date: May 30, 2013

Abstract

We consider several models of control over adversarial channels (i.e., channels which are strategically acting to disrupt the control task, as opposed to merely randomly dropping packets or blocking messages), as idealizations of denial-of-service and other attacks on networked control systems.

We study the resulting zero-sum stochastic games between jammer and controller, prove that the value exists for general formulations, and provide necessary and sufficient conditions for the existence of saddle-point equilibria in mixed strategies. These correspond to situations where the jammer randomizes in a region of the plant's state space, and thus can potentially “masquerade” as a legitimate (non-malicious but imperfect) stochastically packet-dropping channel. Implications in terms of signature of an attack and possible detection mechanisms are then discussed.

Parts of this work are joint with V. Ugrinovskii (EE, University of New South Wales at ADFA), A. Gupta, and T. Basar (UIUC).

Biography

Cedric Langbort is currently on sabbatical at UC Berkeley from the University of Illinois at Urbana-Champaign (UIUC), where he is an associate professor of Aerospace Engineering and affiliated with the Decision & Control Group at CSL. Prior to joining UIUC in 2006, he studied at the Ecole Nationale Superieure de l'Aeronautique et de l'Espace - Supaero in Toulouse (France), the Institut Non-Lineaire in Nice, and Cornell University, from which he received his Ph.D. in January 2005. He also spent a year and a half as a postdoctoral scholar in the Center for the Mathematics of Information at Caltech. He works on applications of control, game, and optimization theory to a variety of fields; most recently to “smart infastructures” problems within the Center for People & Infrastructures which he co-founded and co-directs at CSL. He is a recipient of the NSF CAREER Award and the advisor of a IEEE CDC best student paper award recipient.