US Patent 7124155 Latching electronic circuit for random number generation

A physical random number generator has a bi-stable latch that operates to generate a random number bit in response to a reception of one or more voltage input signals and a clock signal. A voltage source provides the voltage input signal(s) for provoking the bi-stable latch into a metastable state. A clock provides the clock signal for triggering the bi-stable latch. When triggered, the bi-stable latch latches the random number bit as a function of its metastable state provoked by the voltage input signal(s).