Abstract: A device is provided. The device includes: a plurality of physically unclonable function (PUF) cells, each of the plurality of PUF cells including at least one logic gate and being configured to generate an output signal based on at least one threshold level of the at least one logic gate; a signal generator configured to generate an input signal that is provided to each of the plurality of PUF cells; and a controller configured to, in a test mode, generate a control signal to control the signal generator to vary the input signal to control the plurality of PUF cells to output a plurality of output signals according to the input signal, and identify at least one weak PUF cell from among the plurality of PUF cells based on the output signal generated by the at least one weak PUF cell being an unstable output signal. The controller is further configured to disconnect the plurality of PUF cells from the signal generator in a normal mode.

Abstract: A random number generator according to example embodiments includes an initial random number generator configured to generate an initial random number, a self-timed ring (STR) oscillator configured to receive the initial random number, the STR oscillator having a plurality of ring stages generating, in response to a clock, either a bubble that does not change an output state of a previous clock or a token changing the output state of the previous clock, a duty corrector configured to adjust a duty of each of output values of the ring stages, and a sampling circuit configured to sample a random number using a logic operation from the duty-corrected output values.

Abstract: A random number generating circuit includes: an oscillation circuit including a plurality of first delay elements connected to each other in series to generate an oscillation signal; a sampling circuit including a plurality of second delay elements connected to each other in series to generate a plurality of sampling signals by sampling the oscillation signal at a plurality of sampling points in time based on the plurality of second delay elements; and a random number determining circuit configured to generate a random number based on a target sampling point in time associated with a target sampling signal in which a first logic level transition occurs from among the plurality of sampling signals, wherein the plurality of sampling points includes the target sampling point.