Cryptographic system with concealed work factor
US6424713B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 18, 1997 |
| Grant date | Jul 23, 2002 |
| Priority date | — |
| Expiry date | Nov 18, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/1675
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A cryptographic key is provided for cryptographically processing information. A first key is generated according to a key generator scheme. A key space of the first key is reduced in accordance with a key space reduction scheme. The reduced key space is distributed over a larger key space in accordance with a one-way key space distribution function to provide the cryptographic key. The cryptographic key has an associated first work factor for a person without knowledge of the key space distribution function, and an associated second work factor which is less than the first work factor for a person with knowledge of the key space distribution function. Information is cryptographically processed using the cryptographic key, and a new key is generated at a rate of R keys per second to provide a desired protection factor P=W/RZ for a cryptographic system having a lifetime Z.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.