Optimal and Game-Theoretic Deployment of Security Investments in Interdependent Assets

We introduce a game-theoretic framework to compute optimal and strategic security investments by multiple defenders. Each defender is responsible for the security of multiple assets, with the inter-dependencies between the assets captured by an interdependency graph. We formulate the problem of computing the optimal defense allocation by a single defender as a convex optimization problem, and establish the existence of a pure Nash equilibrium of the game between multiple defenders. We apply our proposed framework in two case studies on interdependent SCADA networks and distributed energy resources, respectively. In particular, we investigate the efficiency loss due to decentralized defense allocations.