Random number generator having a transistor that generates an analog random telegraph signal (RTS) having a first or second signal state, a RTS detection unit for detecting the RTS generated by the transistor, a RTS sampling unit that supersamples the RTS detected by the RTS detection unit and thus generates a digitized RTS, a signal state duration detection unit that determines, from the digitized RTS, a first time variable representing the time duration of at least one first signal state of the generated RTS and a second time variable representing the time duration of at least one second signal state of the generated RTS, and a random number conversion unit, which is coupled to the signal state duration detection unit, and that generates a random number from the first time variable and the second time variable.