Disclosed herein is a true random number generator (TRNG). The TRNG includes a cavity filled with tritium and an electronic sensor constructed to detect energy from the decay of the tritium. The sensor produces a signal for the detected energy, and an amplifier amplifies the signal while a filter filters the signal. A processor (a) determines whether the signal represents decay events for tritium; (b) sets a timer to determine the time period between decay events; (c) based on the time period in step (b), assigns a value of a 0 or a 1; (d) stores the value in a memory; (e) repeats steps (b)-(d), resulting in a string of values; and (f) generates a true random number based on the string of values. This TRNG may be formed on an integrated circuit.