Storage device and operating method thereof

A storage device comprising:

• a nonvolatile memory comprising a memory cell array;
• a physically unclonable function (PUF) circuit configured to generate PUF data, based on an output of the memory cell array;
• and
• a memory controller configured to transmit a first PUF data request signal to the PUF circuit, based on first authentication pin information received from a host, and generate a first authentication key based on the first authentication pin information and first PUF data received from the PUF circuit,
• wherein the PUF circuit is further configured to generate the first PUF data by excluding, from the output of the memory cell array, an output of an edge bit cell group and an output of an intermediate bit cell group, and
• wherein the edge bit cell group has a lowest threshold voltage or a highest threshold voltage, and the intermediate bit cell group has a threshold voltage corresponding to a PUF reference voltage level.

A method of operating a storage device, which comprises a memory cell array and a physically unclonable function (PUF) circuit to support a PUF, the method comprising:

• identifying a first memory cell group and a second memory cell group of the memory cell array;
• setting a first exclusion area, which has a threshold voltage equal to or greater than a first read level and less than a second read level, in the second memory cell group;
• setting a second exclusion area, which has a threshold voltage less than a third read level that is less than the first read level, in the second memory cell group;
• setting a third exclusion area, which has a threshold voltage equal to or greater than a fourth read level that is greater than the second read level, in the second memory cell group;
• setting a PUF reference voltage;
• obtaining an output of the second memory cell group by applying the PUF reference voltage to the second memory cell group;
• and
• generating PUF data by excluding, from the output of the second memory cell group, an output of the first exclusion area, an output of the second exclusion area, and an output of the third exclusion area.