SPARTA-COTS: A Laser Probing Approach for Sequential Trojan Detection in COTS Integrated Circuits

Rapid advancements in integrated circuit (IC) technology have been led by the private sector. This leadership has resulted in a widespread dependence of commercial-off-the-shelf (COTS) components in our electronic systems. However, being dependent upon potentially compromised hardware serves as a threat to our security. Hardware Trojans, which can extract sensitive information and disrupt system operations, can be inserted into COTS ICs by untrusted design and fabrication facilities. Checking for the existence of Trojans using conventional methods requires a complex test process and design-level modifications, which requires trusted design information, making them unsuitable for COTS components. On the other hand, for a high confidence detection of Trojans, an exhaustive inspection may be required using destructive reverse-engineering techniques. However, such methods are quite expensive, not applicable to all chips due to their destructive nature, and very time-consuming. In this work, we propose SPARTA-COTS, a non-destructive laser probing approach for Trojan detection in COTS ICs, which detects sequential hardware Trojans by leveraging existing scan chain architecture. SPARTA can differentiate between benign scan flip-flops and malicious sequential hardware Trojans by creating a 2-dimensional frequency activity map of the backside silicon at the clock and scan input frequencies using electrooptical frequency mapping (EOFM). Consequently, SPARTA is capable of confidently identifying Trojan flip-flops using image processing techniques. To validate our claims, we present automated detection results on a 28 nm device.