An Energy-Efficient PUF Design: Computing While Racing

Physical unclonable functions (PUFs) take advantage of the effect of process variation on hardware to obtain their unclonability. Traditional PUF design only focuses on the analog signals of circuits. An arbiter PUF, for example, generates responses by racing delay signals. Implementations of such PUFs usually employ large area and power consumption while providing very low throughput. To address this problem, we propose an energy efficient PUF design in such a way that it races analog signals and computes digital logic simultaneously. More importantly, the analog portion of the circuit (racing) shares a large amount of hardware resources with the digital portion of the circuit (computing) by introducing only small overhead in terms of area and power. Our test results on Spartan-6 field-programmable gate array (FPGA) platforms indicate that by combining the two outputs, our design enables much larger PUF output throughput, better randomness and less power consumption compared to traditional PUFs.