Secure messaging systems
US4866707A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 1, 1988 |
| Grant date | Sep 12, 1989 |
| Priority date | — |
| Expiry date | Mar 1, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2001/0093
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A secure messaging system with several terminals and many system (control) messages transmitted between the various terminals. These messages can deliberate, accidentally change sequence, or be deleted or duplicated. To protect the system against this, an acknowledgement is sent for every message received (except a simple acknowledgement), and each station stores copies of the messages it has sent, deleting them only when acknowledged. When a new message is to be sent or a non-receipt of acknowledgement time-out occurs, a packet is sent with all previous messages in store prefixed to the new message, so the receiving station cannot act on the new message before receiving and acting on the previous messages. There are known means for ignoring duplicated messages. Preferably there is chained serial authentication of the messages in the packet so that even if one is garbled, they can be acted on up to that point. For security and other reasons, user messages are in general not treated similarly but sent only once; with these, error control is a user responsibility.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.