Sequential hardware Trojan: Side-channel aware design and placement

Various design-for-security (DFS) approaches have been proposed earlier for detection of hardware Trojans, which are malicious insertions in Integrated Circuits (ICs). In this paper, we highlight our major findings in terms of innovative Trojan design that can easily evade existing Trojan detection approaches based on functional testing or side-channel analysis. In particular, we illustrate design and placement of sequential hardware Trojans, which are rarely activated/observed and incur ultralow delay/power overhead. We provide models, examples, theoretical analysis of effectiveness, and simulation as well as measurement results of impact of these Trojans in a hardened design. It is shown that efficient design and placement of sequential Trojan would incur extremely low side-channel (power, delay) signature and hence, can easily evade both post-silicon validation and DFS (e.g. ring oscillator based) approaches.