Hardware Trojans are malicious circuits that are secretly inserted into IC chips and circuit boards. They have received widespread attention when news about concerns about contamination into LSIs for 5G is taken up. The goal of the research is to grasp the trends of hardware Trojans, consider countermeasures, disseminate obtained information, and apply countermeasures in collaboration with companies.

While many conventional detection methods use reference chips that do not contain malicious circuits, that is, golden samples, we are challenging the development of detection methods that do not rely on golden samples. We set up a chip observation environment using an optical microscope and succeeded in obtaining a comparison image of two circuits, a light emission image of the moving part, and a perspective image by infrared light. We comprehensively researched the treatises and proposed a unique classification of hardware Trojans. The feature is that powerful detection methods can be associated with each classification, and it is planned to be used in joint research.

We have categorized hardware Trojans in terms of mounting, activation method, and operating characteristics. It is assumed that each hardware Trojan can be attributed from three perspectives. Classified hardware Trojans have different characteristics on each branch of the tree, so it is expected that detection using each characteristic will be possible.