Game theory in infrastructure security V.M. Bier & S. Tas Department of Industrial and Systems Engineering, University of Wisconsin–Madison, Madison, WI 53706, USA Abstract Game-theoretic security models have gained popularity in infrastructure secu- rity in recent years, due to the fact that game theory is suitable for dealing with intelligent threats. In this chapter, we briefly discuss some of the key concepts in game theory, categorize game-theoretic models in infrastructure security and give some examples, and finally discuss some of the limitations of game- theoretical models. Keywords: Game Theory, Attacker–Defender Games, Sequential Games, Infrastructure Security. 1 Introduction There has been increasing use of game-theoretic models in infrastructure secu- rity, especially after September 11, 2001. This is appropriate because game theory considers the intelligent and adaptive nature of an adversarial threat. Therefore, in this chapter we review the application of game-theoretic models to infrastructure security. We first explain some of the important concepts of game theory. Then, we discuss several categories of game-theoretic models in infra- structure security and present some examples. Finally, we discuss some of the limitations of game-theoretic models. A game is a formal description of the strategic interactions of multiple agents (in infrastructure security, typically an attacker and a defender). These interactions can be between those defending a system and those attacking it or between multiple defenders. Game theory assumes that each agent or “player” in a game wishes to find its best strategy given the strategies adopted by the other player(s). This assumption makes it possible for an analyst to make pre- dictions about which strategies players would be likely to choose (under the assumption of rationality); for example, in game theory, an agent would never choose a strategy if it is strictly dominated by another strategy, in the sense that www.witpress.com, ISSN 1755-8336 (on-line) WIT Transactions on State of the Art in Science and Engineering, Vol 54, © 201 WIT Press 2 doi:10.2495/978-1-84564- -/ 562 5 06