Extended key preparing apparatus, extended key preparing method, recording medium and computer program
US6956951B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 20, 2001 |
| Grant date | Oct 18, 2005 |
| Priority date | — |
| Expiry date | Jun 28, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/12
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Intermediate data ai, bi, ci, and di are prepared by an intermediate data preparing equipment 4 from a cryptographic key through a nonlinear type function operation and the like, an extended key preparing equipment 5 selects a [Xr], b [Yr], c [Zr], and d [Wr] corresponding to the number of stages r from the intermediate data, and rearranges the data as well as conducts that of bit operation to prepare extended keys, whereby an extended key preparing apparatus by which an extended key required in the case where common key cryptosystem is applied can be safely prepared at a high speed, a process for preparing such an extended key, and a recording medium used therefor are provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.