Low Overhead Logic Locking for System-Level Security: A Design Space Modeling Approach
Long Lam, Maksym Melnyk, Michael Zuzak · 2024
Integrated circuits are often fabricated in untrusted facilities, making intellectual property privacy a concern. This prompted the development of logic locking, a security technique that corrupts the functionality of a design without a correct secret key. Prior work has shown that system-level phenomena can degrade the security of locking, highlighting the importance of configuring locking in a system. In this work, we propose a design space modeling framework to generate system-level models of the logic locking design space in arbitrary ICs by simulating a small, carefully-selected portion of the design space. These models are used to automatically identify near-optimal locking configurations in a system that achieve security goals with minimal power/area overhead. We evaluate our framework with two experiments. 1) We evaluate the quality of modeling-produced solutions by exhaustively simulating locking in a RISC-V ALU. The models produced by our algorithm had an average R2 > 0.99 for all design objectives and identified a locking configuration within 96% of the globally optimal solution after simulating < 3.6% of the design space. 2) We compare our model-based locking to conventional module-level locking in a RISC-V processor. The locking configuration from our model-based approach required 29.5% less power on average than conventional approaches and was the only method to identify a solution meeting all design objectives.