US Patent 7111029 Random number generating circuit

A random number generating circuit can generate random numbers with high randomness, and can be made as a compact integrated circuit. The random number generating circuit includes an uncertain logic circuit having a flip-flop type logic circuit that gives digital output values not determined definitely by a digital input value, and an equalizing circuit having an exclusive OR operating circuit for equalizing appearance frequencies of “0” and “1” in the digital output values output from the uncertain logic circuit.