Stony Brook Computer Science Dept.
The authors propose InterDependent Defense (IDD) games, a computational game-theoretic framework to study aspects of the interdependence of risk and security in multi-agent systems under deliberate external attacks. Their model builds upon InterDependent Security (IDS) games, a model due to Heal and Kunreuther that considers the source of the risk to be the result of a fixed randomized-strategy. They adapt IDS games to model the attacker's deliberate behavior. They define the attacker's pure-strategy space and utility function and derive appropriate cost functions for the defenders. They provide a complete characterization of Mixed-Strategy Nash Equilibria (MSNE), and design a simple polynomial-time algorithm for computing all of them, for an important subclass of IDD games.