A Similarity Based Circuit Partitioning and Trimming Method to Defend against Hardware Trojans

Nowadays critical integrated circuits are facing the threat of being invaded, counterfeited and pirated by various malicious adversaries. The topic of Hardware Trojan has gained increasing attention in the past decade. Particularly, a plenty of countermeasure approaches have been investigated to obfuscate the design to avoid hostile circuit insertion during the manufacturing stage. Inspired by the observation that circuits have their own internal structure similarity which can be used to obfuscate the design and obstruct malicious insertions, we firstly adopt the metric called circuit similarity to measure the obfuscation degree of circuits, and then propose a novel circuit similarity based partitioning and trimming method to transform the original design into similar sub-circuits. After the procedure of partitioning and trimming, it will be much harder for the attackers to hack certain sub-circuits or gates. Experimental results show that our method can obfuscate the circuit to a desirable circuit similarity with about 30% wire overhead.