Scalable Test Generation for Trojan Detection Using Side Channel Analysis

Abstract

Hardware Trojan detection has emerged as a critical challenge to ensure security and trustworthiness of integrated circuits. A vast majority of research efforts in this area has utilized side-channel analysis for Trojan detection. Functional test generation for logic testing is a promising alternative but it may not be helpful if a Trojan cannot be fully activated or the Trojan effect cannot be propagated to the observable outputs. Side-channel analysis, on the other hand, can achieve significantly higher detection coverage for Trojans of all types/sizes, since it does not require activation/propagation of an unknown Trojan. However, they have often limited effectiveness due to poor detection sensitivity under large process variations and small Trojan footprint in side-channel signature. In this paper, we address this critical problem through a novel side-channel-aware test generation approach, based on a concept of multiple excitation of rare switching (MERS), that can significantly increase Trojan detection sensitivity. This paper makes several important contributions: 1) it presents in detail a scalable statistical test generation method, which can generate high-quality test set for creating high relative activity in arbitrary Trojan instances; 2) it analyzes the effectiveness of generated test set in terms of Trojan coverage; and 3) it describes two judicious reordering methods that can further tune the test set and greatly improve the side channel sensitivity. Simulation results demonstrate that the tests generated by MERS can significantly increase the Trojans sensitivity, thereby making Trojan detection effective using side-channel analysis.