United We Protect: Protecting IP Confidentiality with Integrated Transformation and Redaction

Due to the globally distributed nature of the semiconductor industry, hardware intellectual property (IP) blocks are increasingly subject to attacks on their confidentiality, including IP piracy, cloning, and reverse engineering (RE). Countermeasures like logic locking, state space transformation, and logic redaction, which employ structural and functional transformations on the design, promise to successfully prevent such attacks on hardware IP at different stages of its life cycle. The state-of-the-art logic locking and transformation techniques are generally secure against functional query-based attacks. However, in recent years, researchers have found that they are vulnerable to structural attacks that rely on identifying structural signatures. In comparison, logic redaction techniques replace security-critical logic cones and interconnects in a design with programmable fabrics, thereby protecting a redacted design against structural analysis-based attacks. However, redaction techniques incur significantly higher hardware overheads compared to transformation-based ones. In this paper, we introduce an integrative countermeasure against confidentiality attacks on hardware IPs that unites the complementary benefits of state space transformation using finite state machines (FSMs) and programmable fabric-based logic redaction. We provide an electronic design automation (EDA) framework based on the proposed algorithm that interfaces with commercial tool flow. We demonstrate the security and overhead benefits through theoretical and experimental analysis using a complete software implementation of the proposed countermeasure. We use several open-source benchmark IPs to show that the proposed unified approach provides significantly higher protection than transformation-based solutions with much lower overhead than redaction-based ones.