Golden-Free Hardware Trojan Detection Using Self-Referencing

The globalization of the semiconductor supply chain has developed a new set of challenges for security researchers. Among them, malicious alterations of hardware designs at an untrusted facility, or Trojan insertion, are considered one of the most difficult challenges. While side-channel analysis-based hardware Trojan detection techniques have shown great potential, most solutions, proposed over the past decade, require the availability of golden (i.e., Trojan-free) chips and are susceptible to process variations. Few techniques that do not require a golden chip depend on simulation-based modeling of the side-channel signature, which may not be reliable for differentiating between process and Trojan induced variations. Furthermore, most of these techniques are evaluated either using very few Trojan inserted chips or simulation-based test setup. Spatial and temporal self-referencing-based detection mechanisms proposed earlier effectively eliminate the need for a golden chip and the impact of process variations. However, these techniques have not been adequately studied to achieve high detection sensitivity. In this article, we propose a golden-free multidimensional self-referencing technique that analyzes the side-channel signatures in both the time and frequency domains to significantly broaden the Trojan coverage and strengthen the detection confidence. We introduce a fully automated detection framework containing systematic methodologies for test generation, signature extraction, signal processing, threshold calculation, and metric-based decision-making that effectively enables the synergistic self-referencing approach. Finally, we evaluate the proposed technique through a comprehensive hardware measurement setup consisting of 96 Trojan-inserted test chips. Along with achieving a high detection coverage, we demonstrate that the analysis of spatial and temporal discrepancies in both frequency and time domains helps to reliably detect small hard-to-detect Trojans under process and measurement induced variations.