Optimal Security Investments in Networks of Varying Size and Topology

This paper looks at network security from a game-theoretic point of view. Through the formulation and examination of increasingly complex scenarios, we formulate a model for utility-based security decisions. We look at the decision for one person to buy security software for herself and to buy security software in the context of two or more people. By modeling security as a public good, we examine externalities that players impose upon each other. We then examine Olson´s theory of groups in a network security context to evaluate the effect of network size on optimal decision-making. We also discuss network topologies to investigate the limitations of the common game-theoretic interdependent security models. We conclude that these models work well for small to medium-sized networks with fairly uniform topologies.