Method of extending the validity of a cryptographic certificate
US5373561A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1992 |
| Grant date | Dec 13, 1994 |
| Priority date | — |
| Expiry date | Dec 21, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/60
- WIPO fieldIT methods for management
- WIPO sectorElectrical engineering
Abstract
A cryptographic certificate attesting to the authenticity of original document elements, such as time of creation, content, or source, will lose its value when the cryptographic function underlying the certifying scheme is compromised. The present invention provides a means for extending the reliability of such a certificate by subjecting, prior to any such compromise, a combination of the original certificate and the document digital representation from which that certificate was derived to a scheme based on a different and ostensibly less vulnerable function. The new certificate resulting from this procedure extends the validity of the original authenticity by implacably incorporating the original certificate at a time when that certificate could only have been derived by legitimate means.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.