Patent ID: 8850281

Claim:
A digital signature generation device comprising: a hardware public physically unclonable circuit comprising a plurality of interconnected components, each of the components having an inherent characteristic, not all of the components having an identical value for the inherent characteristic, the inherent characteristics causing transitory states at outputs of at least some of the components during a transition period, the transition period being between a time that an input to the hardware public physically unclonable circuit is changed and a time that all outputs of the hardware public physically unclonable circuit have reached a final value in response to the input being changed, the interconnection of the components and the inherent characteristics providing the hardware public physically unclonable circuit with unique operational characteristics capable of being parameterized; an input register for loading input signals into the hardware public physically unclonable function; and two or more output registers respectively connected to outputs of selected components within the hardware public physically unclonable circuit for sampling the outputs of the selected components for at least one predetermined time during the transition period to provide a digital signature value, wherein the sampled outputs result in differing digital signature values depending on when the output values of the selected components are sampled by the output registers.