US Patent 10153035 SRAM-based authentication circuit

A memory device includes a memory cell array comprising a plurality of memory cells wherein each of the plurality of memory cells is configured to be in a data state, and a physically unclonable function (PUF) generator. The PUF generator further includes a first sense amplifier, coupled to the plurality of memory cells, wherein while the plurality of memory cells are being accessed, the first sense amplifier is configured to compare accessing speeds of first and second memory cells of the plurality of memory cells, and based on the comparison, provide a first output signal for generating a first PUF signature.