Identifying and Measuring Security Critical Path for Uncovering Circuit Vulnerabilities

Hardware is an increasingly attractive attack surface since it controls low-level access to critical resources like cryptographic keys, personally identifiable information, and firmware. Unfortunately, it is difficult to assess the security vulnerabilities of a hardware design, which is a consequence of too few hardware security design tools and metrics. In this work, we describe important security qualities of hardware designs by formalizing hardware security metrics. We introduce the concept of security critical path and show how it can be used to evaluate properties related to confidentiality, integrity, and timing channels. We describe techniques for evaluating the security critical paths and assess their effectiveness in uncovering security flaws in a number of different hardware designs.