Method of generating random numbers

• US 6,857,003 B2
• Filed: 07/12/2001
• Issued: 02/15/2005
• Est. Priority Date: 07/24/2000
• Status: Expired due to Fees

• Current Assignee: Niigata University
• Original Assignee: Niigata University
• Inventors: Saito, Yoshiaki
• Primary Examiner(s): Mai, Tan V.
• Application Number:
  US09/904,329
• Publication Number:
  US 20020042806A1
• Time in Patent Office: 1,314 Days
• Field of Search: 708/801, 708/3, 708250-256, 331/78
• US Class Current: 708/801
• CPC Class Codes: G06F 7/588 Random number generators, i.e. based on natural stochastic processes

Abstract

A method of generating random numbers comprises: generating a first noise and passing the first noise through a first high pass filter which removes a periodic component contained in the first noise to produce a first noise signal having 1/f characteristic; generating a second noise and passing the second noise through a second high pass filter which removes a periodic component contained in the second noise to produce a second noise signal having 1/f characteristic; supplying the first and second noise signals to a differential circuit to derive a different signal between the first noise signal and said second noise signal; and generating, from the different signal, random numbers which do not have a periodicity due to 1/f characteristics of the first and second noise signals.

Claims

1. A method of generating random numbers comprising the steps of:

generating a first noise and passing the first noise through a first high pass filter which removes a periodic component contained in the first noise to produce a first noise signal having 1/f characteristic from a first noise generator circuit and;

generating a second noise and passing the second noise through a second high pass filter which removes a periodic component contained in the second noise to produce a second noise signal having 1/f characteristic from a second noise generator circuit;

supplying said first and second noise signals having 1/f characteristic to a differential circuit to derive a difference signal between said first noise signal and said second noise signal; and

generating, from said difference signal, random numbers which do not have periodicity due to 1/f characteristics of the first and second noise signals.

2. A method according to claim 1, wherein the difference signal produced by the differential circuit is converted by an analog-digital converting circuit into a digital signal, and the thus converted digital signal is outputted as random numbers.

3. A method according to claim 2, wherein nature of the random numbers is adjusted by changing sections of the digital signal.

4. A method according to claim 2, wherein a single digit is obtained from a single bit or a plurality of bits of the digital signal generated from said analog-digital converting circuit, the thus obtained digit is compared with a predetermined threshold level, and when a digit is equal to or larger than the threshold level, “

1”

of a binary number is allocated and when a digit is smaller than the threshold level, “

0”

of binary number is allocated.

5. A method according to claim 4, wherein probabilities of occurrence of “

1” and

“

0”

are detected for a given period, and said threshold level is adjusted such that the probabilities of occurrence of “

1” and

“

0”

become to given values.

6. A method according to claim 5, wherein said threshold level is adjusted such that the probabilities of occurrence of “

1” and

“

0”

become to 0.5 or about 0.5.

7. A method according to claim 5, wherein said period during which the probabilities of occurrence of “

1” and

“

0”

are detected is adjusted.

8. A method according to claim 7, wherein said period during which the probabilities of occurrence of “

1” and

“

0”

are detected is adjusted in accordance with the generated random numbers.

9. A method according to claim 1, wherein said first and second noises are generated by a first noise generating element provided in a first noise generating circuit and a second noise generating element provided in a second noise generating circuit, respectively.

10. A method according to claim 1, wherein the generating of the first noise or the second noise is formed by diode or resistor.