R2D2: Runtime reassurance and detection of A2 Trojan

With the globalization of semiconductor industry, hardware security issues have been gaining increasing attention. Among all hardware security threats, the insertion of hardware Trojans is one of the main concerns. Meanwhile, many current Trojan detection solutions follow the assumption that the hardware Trojan itself should be composed of digital logic. This assumption is invalidated by recently proposed analog Trojans which are extremely small and can detect rare events. This paper proposes a runtime hardware Trojan detection method which is geared towards detecting such advanced Trojans. The principle of this method is to guard a set of concerned signals, and initiate a hardware interrupt request when abnormal toggling events occur in these guarded signals. To prove the effectiveness of this method, we design a processor based on ARMv7-A&R ISA, and insert an analog Trojan into the processor. We fabricated the design in the SMIC 130 nm process and demonstrate the effectiveness of the proposed methodology.