Interoperable cryptographic key recovery system
US5796830A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1996 |
| Grant date | Aug 18, 1998 |
| Priority date | — |
| Expiry date | Jul 29, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L9/0894
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A cryptographic key recovery system that is interoperable with existing systems for establishing keys between communicating parties. The sender uses a reversible key inversion function to generate key recovery values P, Q and (optionally) R as a function of a session key and public information, so that the session key may be regenerated from the key recovery values P, Q and (if generated) R. Key recovery values P and Q are encrypted using the respective public recovery keys of a pair of key recovery agents. The encrypted P and Q values are included along with other recovery information in a session header accompanying an encrypted message sent from the sender to the receiver. The key recovery agents may recover the P and Q values for a law enforcement agent by decrypting the encrypted P and Q values in the session header, using their respective private recovery keys corresponding to the public keys. The R value, if generated, is not made available to the key recovery agents, but is ascertained using standard cryptanalytic techniques in order to provide a nontrivial work factor for law enforcement agents. The receiver checks the session header of a received message to ensure that th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.