An Efficient Technique to Detect Stealthy Hardware Trojans Independent of the Trigger Size

Abstract

Detecting Hardware Trojans (HTs) in digital circuits might be a challenging problem due to the stealthy nature of these malicious unwanted guests. The trigger part which is supposed to activate the Trojan under exceptional conditions, is often inserted at rare–switched nets of the design to hide them from usual verification tests mechanisms. Existing Trojan detection methods straggle in detecting modern Trojans which mostly have exploit multiple-input triggering parts to drive small payloads. Addressing such multiple-input triggering circuitries needs wise activation mechanisms with a reasonable time-complexity to serve as a feasible solution for large commercial designs. In this paper we present an algorithm which analyses fan-in and fan-out cones along with the Hardware Trojan susceptibility of the most suspicions nets of gate-level designs to find subsets of them which could most probably activate an inserted HT. Then a fast test vector generation algorithm is proposed to excite as many susceptible nets as possible for achieving the multiple nets excitation requirement. The results of applying the proposed algorithms on the TRIT and trust-hub benchmark suites show an average of 89% HT detection coverage while the required maximum run time is much smaller than the previous state of the art methods.