US 6,807,553 B2 · Digital true random number generator circuit

Abstract

A digital true random number generator circuit, comprising a linear feedback shift register having an input and an output, a system clock having a system clock frequency value for driving the shift register, and a plurality of free running oscillators operatively connected to the input of the shift register. The oscillators and the system clock having different oscillation frequency values, the greatest common divisor of which having the value one, thereby avoiding locking of the oscillators and the system clock.

Drawings

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Drawings

Claims10

Dependent claims

A digital true random number generator circuit, comprising:

a linear feedback shift register having an input and an output;
a plurality of free-running oscillators each operatively connected to a separate input of a single exclusive OR-circuit;
said exclusive OR-circuit having an output operatively connected to an input of a latching circuit;
said latching circuit having an output operatively connected to the input of said linear feedback shift register and configured to drive said linear feedback shift register;
and
a system clock operatively connected to a clock input of said latching circuit and having a system clock frequency value configured to drive said linear feedback shift register,
wherein said free-running oscillators and said system clock have different oscillation frequency values, the greatest common divisor of the different oscillation frequency values having the value one.

4 more elements

Dependencies are inferred from the claim text.

Description2,090 words

Summary1,006 words

#1. Field of the Invention

#The invention relates, in generals to circuits and techniques for generating random numbers, and in particular to digital semiconductor circuits for generating true random numbers.

#2. Discussion of the Background

Brief description of the drawings3 figures

#The present invention will now be described with reference to the accompanying drawings, wherein:

#FIG. 1 discloses schematically an embodiment of a true random number generating circuit according to the invention;

#FIG. 2 discloses schematically a specific embodiment of a linear feedback shift register for use in the true random number generator circuit according to the invention; and

Detailed description998 words

#FIG. 1 is a logic block diagram of an embodiment of a digital true random number generator circuit according to the invention. It incorporates a Linear Feedback Shift Register (LFSR) 4 having an input 4a, and an output 4b. LFSR's are known in practice to those skilled in the art and do not need to be further elucidated here.

#In order to avoid the above described problem of “locking” of a driving oscillator and a system clock or counter 3, in accordance with the present invention, a plurality of free running oscillators 10, 20, 30 operatively connects to the input 2a of the LFSR 4. The oscillators have oscillation frequency values which differ among each other and of the system clock frequency value in a manner such that their greatest divisor is of the magnitude one.

#In the embodiment of FIG. 1, for illustration purposes, three free running oscillators 10, 20, 30 are shown. However, those skilled in the art will appreciate that other numbers of oscillation devices may be used for the purpose of the present invention. In the embodiment shown, each free running oscillator 10, 20, 30 is constructed as a ring oscillator having a plurality of cascade connected inverter circuits 101-109, 201-207, 301-305 and furthermore having an output 10out, 20out, 30out, respectively.

Facts

Application

09/839,121Filed 23 Apr 2001

Published

US 2002/0156819 A124 Oct 2002

Granted

19 Oct 2004

Term ended

19 Nov 2022

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 575 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification5 codes

H04L 9/0861
Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords: generation of secret information…
G06F 7/588
Random or pseudo-random number generators: random number generators, i.e. based on natural stochastic processes
G06F 7/584
Pseudo-random number generators: using finite field arithmetic, e.g. using a linear feedback shift register
H04L
Digital communication

Timeline

23 Apr 2001Application filedUS 09/839,121
9 Aug 2001Assigned to Pijnenburg Beheer N.V.assignment of assignor's interest
8 Jan 2002Assigned to Pijnenburg Beheer N.V.corrective assignment to correct the incorrect application number from 09/839,131 to 09/839121. document previously recorded at reel 012054 frame 0031.
24 Oct 2002PublishedUS 2002/0156819 A1
9 Sep 2004Assigned to Safenet B.V.assignment of assignor's interest
19 Oct 2004GrantedUS 6,807,553 B2
6 Apr 2007Assigned to Safenet, Inc.change of name
16 Apr 2007Assigned to Deutsche Bank Trust Company Americas, AS Collateral Agentfirst lien patent security agreement
19 Apr 2007Assigned to Deutsche Bank Trust Company Americas, AS Collateral Agentsecond lien patent security agreement
19 Mar 2010Assigned to Safenet, Inc.partial release of collateral
13 Aug 2010Assigned to Authentec, Inc.assignment of assignor's interest
4 Feb 2013Assigned to Inside Secureassignment of assignor's interest
27 Feb 2019Assigned to Glas SAS, AS Security Agentsecurity interest
7 Oct 2019Assigned to Verimatrixchange of name
16 Oct 2019Assigned to Verimatrixchange of address
21 Nov 2019Assigned to Inside Securepartial release of security interest in patent collateral
12 Dec 2019Assigned to Rambus Inc.assignment of assignor's interest
19 Nov 2022Term endedEstimated, includes 575 days of adjustment

Digital true random number generator circuit

Life of this patent

Digital true random number generator circuit

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims10

Description2,090 words

Drawings

Classification5 codes

Life of this patent

Description2,090 words