Patent ID: 7702704

Claim:
A random number generating method in an electronic device using a random number, the method comprising: providing an electronic device including a plurality of unit circuits each having a corresponding noise source, including a first logic circuit and a second logic circuit, each logic circuit having a same shape and each being formed through a same fabrication process on a substrate of semiconductor material, and an amplifier circuit to which an output of the corresponding noise source is supplied, the electronic device also including a signal variation detector circuit to which outputs from said plurality of unit circuits are supplied; causing said plurality of unit circuits and said signal variation detector circuit to perform operations including: generating a binary signal at each unit circuit by amplifying noise superposed on a differential voltage of threshold voltages of the first and the second logic circuits of the respective unit circuit; generating, with said signal variation detecting circuit, an output signal in response to a variation in any of the binary signals outputted from the respective unit circuits; and combining a plurality of the binary signals outputted from the signal variation detecting circuit to generate a random number.