Trust in IoT Devices: A Logic Encryption Perspective

Tremendous technological advancement has led to the development of an ecosystem of highly connected ubiquitous computing devices called the Internet of Things (IoT). Considering the sensitive nature of the data collected by the IoT devices, it is essential to ensure the security of these devices. Logic encryption is a popular design-for-trust technique used for protection against hardware IP piracy, design counterfeiting, and hardware Trojan insertion. The introduction of various attack methods that leverage vulnerabilities in known logic encryption techniques has prompted the development of new techniques able to thwart the proposed attacks. Major research effort in the field of logic encryption focuses on increasing resilience to known and potential attacks while often ignoring considerations of cost overhead, especially die area and power consumed. Since area and power optimization are key aspects in the design and development of most IoT devices, it is important to evaluate the cost incurred by logic encryption schemes, especially in the context of these two metrics. In this paper, we survey some of the most popular logic encryption and decryption techniques proposed in the past decade. An analysis of the area and power overhead of these logic encryption techniques using several standard benchmark circuits is presented to assess their suitability for resource constrained systems.