Patent ID: 8861736

Claim:
A method of manufacturing a secure device having a physical unclonable function, the method comprising: embedding a phase change memory in the secure device, the phase change memory comprising a plurality of cells; and setting the phase change memory in a manner that results in a non-uniform phase being exhibited over the plurality of cells, wherein the non-uniform phase is manifested by at least two of the plurality of cells being set to different phases, wherein each of the different phases is one of fully amorphous, fully crystalline, or between fully amorphous and fully crystalline, and wherein the non-uniform phase comprises the physical unclonable function; measuring a property of the phase change memory for deriving a signature having one or more physical unclonable function values; and deriving a binary key from the signature, wherein the binary key is derived by applying a threshold to the one or more physical unclonable function values for conversion into a binary code.