Microsecond-Level Temperature Variation of Logic Circuits and Influences of Infrared Cameras’ Parameters on Hardware Trojans Detection

Abstract

Currently, hardware Trojans have posed a serious threat to the integrated circuit security. A novel approach using chips’ infrared radiation to detect Trojans on a second scale was proposed in 2014. However, the temperature differences can be distinguishable on a microsecond scale between the normal areas in normal chips and the corresponding infected areas in chips with Trojans. As a result, the second-level detection can influence the detection accuracy reversely because of the temperature balance. On the other hand, infrared cameras’ ability to detect Trojans is determined by three parameters. They are the noise equivalent temperature difference (NETD), the pixel size and the frame frequency. It will be of benefit to Trojans detection using infrared cameras, if we determine the influences of the three parameters on detection. In this paper, we utilize finite element analysis to simulate the microsecond-level temperature variations of a fixed pixel-size silicon substrate while logic circuits on this size silicon substrate vary and operate under different challenges. Then, we find that the distinguishable time between different cases is on a microsecond scale according to a normal NETD. Based on our simulation results, an increasing step size (ISS) approach is proposed to capture dies’ microsecond-level infrared maps accurately using the low frame frequency infrared cameras. Finally, we analyze the temperature variations while a fixed logic circuit under a fixed challenge is operating on the different pixel-size silicon substrates. Based on the results, we get the link between NETD and the pixel size on the Trojan detection.

This work was supported by the National Natural Science Foundation of China (NSFC, grants no. 61471375).