Detour: Layout-aware Reroute Attack Vulnerability Assessment and Analysis

Over the past several decades, the rate of innovation and performance enhancement in integrated circuits (ICs) is mind-boggling, making them ubiquitous in a wide spectrum of critical applications ranging from military infrastructure to personal healthcare. Lately, however, physical security has become a prime concern given the valuable assets that ICs process and store. Out of all invasive attack vectors, micro-probing attacks emerge as one of the most threatening because they utilize advanced focused ion beam (FIB) systems for post-silicon secret eavesdropping and circuit editing at a negligible footprint. As an evolved variant of micro-probing attacks, reroute attacks can effectively abolish built-in shielding countermeasures to access the security-sensitive signals underneath. To mitigate and tackle such challenges, we propose a layout-level framework called Detour to automatically evaluate the exploitable vulnerabilities. Specifically, we utilize a linear programming-based scheme to determine the layout-aware added traces length of reroute attempts given target assets. Experimental results show that all of the shielded designs act better than the non-shielded structures against reroute attack, and that the orthogonal two-layer shield structure has better performance than the parallel two-layer shield structure. In addition, we also consider both the independent and dependent scenarios based on whether circuit edit locations are allowed to interfere with each other or not. Our results show that a near 50% increase in attack cost can occur when utilizing our more realistic dependent estimation method.