Small Trojan Testing Using Bounded Model Checking

Abstract

With the widely using of VLSI circuits, their security issue has been a critical factor to the security of the modern system. In this paper, we propose a testing method using Bounded Model Checking (BMC) to test the small Trojan that is injected by slightly modifying the original design. First, we implement physical inspection on the training chip set that has the same function but from different sources, and extract suspicious circuit pairs by pairwise comparison on the chips. Second, we use BMC to detect the inconsistent functions on the suspicious circuit pairs. Third, we collects these inconsistent functions as well as their corresponding input sequences into a vulnerability scanner library, and test the other chips using that library. Experimental results show the proposed method can detect the small Trojan in sequential circuits with large sequential depth using an optimized computing time. Furthermore, the method can accurately distinguish small Trojans from circuit optimizations in logic synthesis.