Dynamic Game for Strategy Selection in Hardware Trojan Attack and Defense

The offshore outsourcing introduces serious threats to semiconductor suppliers and integrated circuit(IC) users for the possibility of hardware trojans (HTs). To alleviate this threat, IC designers use the active defenses against HTs which are implanted by the malicious manufacturer. In this paper, a game-theoretic framework based on fuzzy theory is proposed to obtain the optimal strategy. It analyzes the interactions between the active defense designer and the malicious manufacturer. The attack and defense on IC is formulated as a noncooperative dynamic game. The active defense strategy is decided in IC design. And the overall payoff including design costs and losses avoided is optimized. Subsequently, the HT is implanted considering the implantation cost as well as the damage caused by it. To solve the problem of uncertain payoff caused by insufficient information, fuzzy variable is used to represent the influence of the defense coverage rate on the payoff. In order to verify the applicability of fuzzy variable in dynamic game framework, the existence of pure strategy Nash equilibrium in the game is proved. A solution algorithm for pure strategy Nash Equilibrium is proposed to obtain the optimal strategy of attacker and defender. Thanks to the case study of Field Programmable Gate Array (FPGA), the proposed framework is feasible for HT attack and defense game.