CONFIGURABLE RANDOM NUMBER GENERATOR

• US 20090110188A1
• Filed: 10/29/2008
• Published: 04/30/2009
• Est. Priority Date: 10/30/2007
• Status: Active Grant

• Current Assignee: SanDisk IL Ltd. (Western Digital Corporation)
• Original Assignee: SanDisk IL Ltd. (Western Digital Corporation)
• Inventors: Krotman, Roy, Kun, Michael, Dror, Itai, Dolgunov, Boris, Minz, Leonid
• Granted Patent: US 8,130,950 B2
• Time in Patent Office: Days
• US Class Current: 380/28
• CPC Class Codes: G06F 7/58 Random or pseudo-random number generators
• CPC Class Codes: G06F 7/588 Random number generators, i.e. based on natural stochastic processes
• CPC Class Codes: H04L 9/0861 Generation of secret information including derivation or calculation of cryptographic keys or passwords

Abstract

A method for random number generation includes generating random number sequences using a Random Number Generator (RNG) circuit having an externally-modifiable configuration. The RNG circuit generates a first random number sequence having a first measure of randomness, and modifies the configuration of the RNG circuit, causing the RNG circuit to generate a second random number sequence having a second measure of the randomness, indicating a degree of the randomness that is no less than the first measure.

Claims

1. A method for random number generation, comprising:

generating random number sequences using a Random Number Generator (RNG) circuit having an externally-modifiable configuration; and

when the RNG circuit generates a first random number sequence having a first measure of randomness, causing the RNG circuit to generate a second random number sequence having a second measure of the randomness, which indicates a degree of the randomness that is no less than the first measure, by modifying the configuration of the RNG circuit.

2. The method according to claim 1, wherein causing the RNG circuit to generate the second random number sequence comprises processing the first random number sequence so as assess the first measure of the randomness, and modifying the configuration responsively to the assessed first measure of the randomness.

3. The method according to claim 1, wherein causing the RNG circuit to generate the second random number sequence comprises accepting an external command and modifying the configuration responsively to the external command.

4. The method according to claim 1, wherein causing the RNG circuit to generate the second random number sequence comprises modifying the configuration periodically.

5. The system according to claim 1, wherein causing the RNG circuit to generate the second random number sequence comprises modifying the configuration by randomly selecting a modified configuration from a set of possible configurations.

6. The method according to claim 1, wherein generating the random number sequences comprises operating at least one ring oscillator having configurable feedback taps, and wherein modifying the configuration comprises reconfiguring the feedback taps.

7. The method according to claim 1, wherein generating the random number sequences comprises operating multiple cascaded inverters arranged in a ring, and wherein modifying the configuration comprises modifying a number of the inverters in the ring.

8. The method according to claim 1, wherein generating the random number sequences comprises operating multiple oscillators producing respective multiple outputs and combining the multiple outputs in accordance with a combining function to produce the random number sequences, and wherein modifying the configuration comprises modifying the combining function.

9. The method according to claim 1, wherein generating the random number sequences comprises applying a whitening function to the random number sequences, and wherein modifying the configuration comprises modifying the whitening function.

10. The method according to claim 1, wherein generating the random number sequences comprises generating the sequences responsively to one or more initial values, and wherein modifying the configuration comprises modifying the initial values.

11. A method for random number generation, comprising:

carrying out, by a cryptography module, a cryptographic operation on data using random number sequences;

generating the random number sequences, by a Random Number Generator (RNG) circuit, in accordance with an externally-modifiable configuration; and

modifying the configuration of the RNG circuit, by a control unit, when the RNG circuit generates a first random number sequence having a first measure of randomness, so as to cause the RNG circuit to generate a second random number sequence having a second measure of randomness, indicating a degree of randomness that is no less than the first measure.