Pseudorandom number generator
US6044388A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 1997 |
| Grant date | Mar 28, 2000 |
| Priority date | — |
| Expiry date | May 15, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/26
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Pseudorandom numbers are generated in a cryptographic module in a cryptographically strong manner by combining a time-dependent value with a secret value and passing the result through a one-way hash function to generate a hash value from which a random number is generated. The secret value is continually updated whenever the cryptographic module is idle by a first feedback function that generates an updated secret value as a one-way function of the current secret value and the time-dependent value. In addition, the secret value is updated on the occurrence of a predetermined external event by a second feedback function that generates an updated secret value as a one-way function of the current secret value, the time-dependent value and an externally supplied value. Upon power-on reset, if the pseudorandom number generator has not been previously initialized, it initializes itself by resetting the time-dependent and secret values and requiring the second feedback function to perform a predetermined number of updates of the secret value in response to external events. Otherwise, the time-dependent and secret values are restored using values stored in backup registers. A hash of the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.