Security device including physical unclonable function cells, operation method of security device, and operation method of physical unclonable function cell device

A security device comprising:

• a physical unclonable function (PUF) cell array including a plurality of first PUF cells connected with a first word line;
• a control circuit configured to select a target PUF cell of the plurality of first PUF cells and to output a control signal indicating the selected target PUF cell;
• a decoding circuit configured to apply a first voltage to the first word line in response to the control signal;
• a bit line selection circuit connected with a plurality of first bit lines, and configured to output a first target current across a bit line connected with the target PUF cell from among the plurality of first bit lines and a first sum current corresponding to a sum of currents across the remaining bit lines connected with other PUF cells from among the plurality of first PUF cells;
• and
• a bit determining circuit configured to output a target bit of the target PUF cell based on the first target current and the first sum current,
• wherein the security device generates a security key based on the target bit for responding to an authentication request.