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.