# US 11,442,699 B2 · Random number generating circuit and random number generating method

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- Number: US 11,442,699 B2
- Document ID: US11442699B2
- Status: Granted
- Kind: B2
- Application number: 16/756,581
- Filed: 2018-11-21
- Published: 2020-09-10
- Granted: 2022-09-13
- Earliest claimed: 2017-11-28
- Assignees: NEC Corporation
- Applicants: NEC Corporation
- Inventors: Atsushi Kozato
- Web page: https://patentgrep.com/patent/US11442699B2

## CPC

- G06F 7/588: {Random number generators, i.e. based on natural stochastic processes}
- G09C 1/00: Apparatus or methods whereby a given sequence of signs, e.g. an intelligible text, is transformed into an unintelligible sequence of signs by transposing the signs or groups of signs or by replacing them by others according to a predetermined system (cryptographic typewriters G09C3/00)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G09C: CIPHERING OR DECIPHERING APPARATUS FOR CRYPTOGRAPHIC OR OTHER PURPOSES INVOLVING THE NEED FOR SECRECY

## Abstract

To enables to obtain difficult-to-predict random numbers without requiring a more complex circuit configuration, the random number generating circuit is configured to include a light output means, a light receiving means, a current/voltage converting means, a comparing means, a sampling means, and an output means. The light output means outputs light of a prescribed wavelength. The light receiving means receives the light and converts the same into current signals. The current/voltage converting means converts the current signals into voltage signals. The comparing means compares the voltage signals with a reference voltage and converts the voltage signals into binary signals. The sampling means samples, at a cycle set on the basis of the light noise frequency, the binary signals converted by the comparing means and converts the same into bit data. The output means outputs bit string data arranged in the order of conversion of the bit data.

## Claims

### Claim 1

A random number generating method, comprising:
outputting light of a prescribed wavelength;
receiving light and converting the light into a current signal;
converting the current signal into a voltage signal;
converting the voltage signal into a binary signal by comparison with a reference voltage;
sampling, at a cycle being set based on a frequency of noise of the light, the converted binary signal, and converting the sampled signal into bit data; and
outputting bit string data in which the bit data are arranged in order of being converted.

### Claim 2 (depends on 1)

The random number generating method according to claim 1, further comprising:
splitting the converted binary signal into a first path and a second path;
inverting potential of the binary signal in the second path; and
alternately sampling the binary signal input from the first path and the binary signal inverted and input from the second path.

### Claim 3 (depends on 1)

The random number generating method according to claim 1, further comprising setting the reference voltage, based on a ratio of one level data frequency and another level data frequency of the sampled bit data.