Physical random number generator, method of generating physical random numbers and physical random number storing medium

• US 6,195,669 B1
• Filed: 09/10/1998
• Issued: 02/27/2001
• Est. Priority Date: 09/12/1997
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Tsunoyama, Shigeaki, Onodera, Toru, Kanemoto, Shigeru
• Primary Examiner(s): Mai, Tan V.
• Application Number:
  US09/150,928
• Time in Patent Office: 901 Days
• Field of Search: 708/3, 708/250-251
• US Class Current: 708/3
• CPC Class Codes: G06F 7/588 Random number generators, i.e. based on natural stochastic processes

Abstract

A physical random number generator including a noise source configured to generate a noise signal, an alternating current AC coupling amplifying device which amplifies the noise signal while removing a direct current DC component therefrom by AC coupling to generate an amplified noise signal, an analog/digital A/D conversion device having an accuracy of not less than two bits which A/D converts the amplified noise signal to digital values composed of bit data of not less than two bits, and a processing device which processes the amplified noise signal and which processes digital values converted from a processed amplified noise signal to generate random number data of not less than two bits with an increased differential nonlinearity as compared to digital values unprocessed by the processing device.

Claims

1. A physical random number generator, comprising:

a noise source configured to generate a noise signal;

an alternating current AC coupling amplifying device configured to amplify said noise signal while removing a direct current DC component therefrom by AC coupling to generate an amplified noise signal;

an analog/digital A/D conversion device having an accuracy of not less than two bits and configured to A/D convert said amplified noise signal to digital values composed of bit data of not less than two bits; and

a processing device configured to process said amplified noise signal prior to A/D conversion and to process digital values converted from a processed amplified noise signal to generate random number data of not less than two bits with an increased differential nonlinearity as compared to digital values unprocessed by said processing device.

2. The physical random number generator according to claim 1, further comprising:

an offset adjusting device configured to obtain a mean value of said digital values converted by said A/D conversion device to generate said mean value as a digital offset adjusting signal, to D/A convert said digital offset adjusting signal to an analog offset adjusting signal, and to subtract said analog offset adjusting signal from said amplified noise signal;

wherein, instead of said amplified noise signal, a subtracted value of said analog offset adjusting signal from said amplified noise signal is input to said A/D conversion device.

3. The physical random number generator according to claim 1, further comprising:

an offset adjusting device configured to obtain a mean value of said digital values converted by said A/D conversion device to generate said mean value as a digital offset adjusting signal to said digital values,

wherein added values of digital offset adjusting signal and said digital signal are output as said random number data.

4. The physical random number generator according to claim 1, wherein:

said A/D conversion device has an accuracy of not less than six bits;

said A/D conversion device takes out at least two bits out of fifth and subsequent bits counted from the highest bit in not less than six bit data composing said digital values converted by said A/D conversion device as taken out data; and

said A/D conversion device generates said taken out data as said random number data.

5. The physical random number generator according to claim 1, wherein:

said A/D conversion device has a conversion range which is wider than a range (N±

σ

), when said digital values converted by said A/D conversion device become the normal distribution of an average N and a variance σ

², and regards said digital values as valid only when said digital values fall in said conversion range.

6. The physical random number generator according to claim 1, wherein:

said processing device includes a differential nonlinearity increasing device configured to add differential nonlinearity-increasing analog data to input values of said A/D conversion device as an offset and to subtract differential nonlinearity-increasing digital data equivalent from said digital values converted from an added amplified noise signal;

wherein resultant subtracted data are output as said random number data.

7. The physical random number generator according to claim 1, wherein:

said processing device includes a differential nonlinearity increasing device configured to add and average a plurality of said digital values converted from said A/D conversion device,

wherein average values of said digital values are output as said random number data.

8. The physical random number generator according to claim 1, wherein a plurality of said A/D conversion devices are provided each with said processing device, wherein:

said processing device includes a differential nonlinearity increasing device configured to add and average a plurality of said digital values converted from said A/D conversion device,

wherein average values of said digital values are output as said random number data.

9. The physical random generator according to claim 1, further comprising;

a pseudo random number generator configured to generate pseudo random number data; and

a differential nonlinearity increasing device configured to add and subtract said digital values converted from said A/D conversion device and said pseudo random number data,

wherein average values of said digital values and said pseudo random number data are output as said random number data.

10. The physical random number generator according to claim 1, wherein:

said noise source generates thermal noise as said noise signal.

11. The physical random number generator according to claim 10, wherein:

said noise source generates said thermal noise of a resistor as said noise signal.

12. The physical random number generator according to claim 10, wherein:

said noise source generates said thermal noise of a semiconductor device as said noise signal.

13. The physical random number generator according to claim 10, wherein:

said noise source generates said thermal noise of a photoelectric conversion surface of a photomultiplier as said noise signal.

14. The physical random number generator according to claim 10, wherein:

said noise source generates said thermal noise generated from a cathode of a vacuum tube as said noise signal.

15. The physical random number generator according to one of claims 10 to 14, further comprising:

a thermostatic device configured to maintain said noise source at a constant high temperature.

16. The physical random number generator according to claim 1, wherein:

said noise source generates fluctuation of electrons generated in a vacuum microelement as said noise signal.

17. A physical random number display device, comprising:

said physical random number generator according to claim 1; and

a display device configured to display data based on said random number data generated from said physical random number generator.

18. A communication equipment, comprising:

said physical random number generator according to claim 1; and

a signal modulation device configured to modulate a signal using said random number data generated from said physical random number generator.

19. A data encoder, comprising:

said physical random number generator according to claim 1; and

an encoding data using said random number data generated from said physical random number generator.

20. A physical random number input device, comprising:

said physical random number generator according to claim 1; and

a bus interface device connected to interface with a data input/output bus of a computer configured to input said random number data generated from said physical random number generator into said computer.

21. A physical random number input device, comprising:

said physical random number generator according to claim 1; and

a network interface device connected to interface with a computer network configured to transmit said random number data generated from said physical random number generator to said computer network in response to a request from a computer.

22. The physical random number generator according to claim 1, further comprising:

a storage device configured to store said random number data and to supply said stored random number data in response to a request to output said random number data.

23. A physical random number storing medium readable by a computer in which said random number data generated by said physical random number generator according to claim 1 are stored.

24. The physical random number storing medium according to claim 23, wherein:

at least one of an examination method of said stored random number data and an examination result of said stored random number data is stored.

25. The physical random number generator according to claim 1, wherein:

said A/D conversion device has a conversion range for its input signal of said amplified noise signal, and regards said digital values as valid only when said input signal falls in said conversion range.

26. The physical random number generator according to claim 1, wherein:

said processing means includes a differential nonlinearity increasing device configured to add and average said digital values converted from said A/D conversion device and secondary digital data provided by and converted from a secondary noise source, said secondary digital data not outputted from said A/D conversion device;

wherein average values of said digital values are output as said processed data.

27. A method of generating physical random numbers, comprising the steps of:

generating a noise signal from a noise source;

amplifying said noise signal while removing a direct current DC component therefrom by alternate current AC coupling to generate an amplified noise signal;

analog/digital A/D converting said amplified noise signal to digital values composed of bit data of not less than two bits;

processing said amplified noise signal prior to A/D conversion; and

processing digital values converted from a processed amplified noise signal to generate random number data of not less than two bits with an increased differential nonlinearity as compared to digital values unprocessed by said processing device; and

outputting generated random number data as an output of said physical random number generator.