Biblio

The threat of inserting malicious logic in hardware design is increasing as the digital supply chains are becoming more deep and span the whole globe. Ring oscillators (ROs) can be used to detect deviations of circuit operations due to changes of its layout caused by the insertion of a hardware Trojan horse (Trojan). The placement and the length of the ring oscillator are two important parameters that define an RO sensitivity and capability to detect malicious alternations. We propose and study the use of ring oscillators with variable lengths, configurable at the runtime. Such oscillators push further the envelope for the attackers, as their design must be undetectable by all supported lengths. We study the efficiency of our proposal on defending against a family of hardware Trojans against an implementation of the AES cryptographic algorithm on an FPGA.

Malicious hardware is a realistic threat. It can be possible to insert the malicious functionality on a device as deep as in the hardware design flow, long before manufacturing the silicon product. Towards developing a hardware Trojan horse detection methodology, we analyze capabilities and limitations of existing techniques, framing a testing strategy for uncovering efficiently hardware Trojan horses in mass-produced integrated circuits.