Security Resource Investment Optimization for Critical Infrastructure Systems: A Game-Theoretic Approach

Motivated by the problem of optimal security resource deployment in critical infrastructure systems, we study a non-zero-sum security game over the substations of a power system in which the player payoffs depend upon the maturity of the security resources at each substation according to NERC-CIP standards. Extending previous work, we give a structural characterization of the possible types of Nash equilibria in our non-zero-sum additive security game model, present feasibility conditions for equilibria of each type, and propose a novel algorithm to compute an equilibrium. Utilizing our characterization of the possible equilibria in additive security games, we propose a method to obtain a suboptimal solution to the problem of maximizing the expected outcome to the system operator by varying the maturity of security resources deployed at each substation and demonstrate the method by simulation.