A Robust Hierarchical FSM Structure for Active IC Metering

Security is the key issue for active IC metering schemes. A hierarchical FSM (HFSM) structure combined with Physically Unclonable Functions (PUFs) is proposed to improve the robustness against brute-force attacks for a classic active IC metering scheme. The proposed HFSM structure uses the PUF outputs to determine the transitional path and then the rest input bits are utilized to improve the security of the structure. The security level of the proposed scheme is analyzed and is compared with the related scheme with the growth of added structure layers. Experiments are conducted to study and compare the area, power and delay overhead of the two schemes. Experimental results on the MCNC’91 benchmarks show that the scheme has exponentially improved the security level with an acceptably low overhead cost.