Securing Medical Devices Against Hardware Trojan Attacks Through Analog-, Digital-, and Physiological-Based Signatures

Corruption of data in embedded and medical devices can cause serious harm if not quickly detected. In this paper, we emphasize the part of the attack surface which entails inserting malicious hardware circuitry (Hardware Trojans) during the manufacturing process of a digital microchip. The Hardware Trojan (HT) is composed of a few gates and attempts to modify the functionality of the chip. Such types of extremely small HTs are hard to detect using other conventional offline HT detection methods, such as side-channel analysis and digital systems test techniques. In our approach, however, we focus on an online method for rapidly detecting HTs at runtime by checking for correct functionality of the underlying hardware. We present an architecture that addresses these threats by splitting the design into a two-chip approach where we generate signatures deep in the hardware during data harvesting, and we then check for these signatures during data processing and encryption for transmission. In addition, we take advantage of known physiological relationships between medical data to ensure the integrity of the data that is processed by the hardware. Our experimental results demonstrate the effectiveness of our HT detection architecture and show that not only can we detect such types of attacks but also that we can distinguish these attacks from actual health problems. Our synthesis results show that our architecture minimally impacts performance and area especially in light of the fact that most of our techniques rely on digital logic modules which are already typically present in modern digital chips for test and other purposes.