Decryption of retransmitted data in an encrypted communication system
US5694473A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 17, 1996 |
| Grant date | Dec 2, 1997 |
| Priority date | — |
| Expiry date | May 17, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L1/1809
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method of decrypting retransmitted parts of a message includes receiving (201) a message comprising encryption synchronization and a plurality of encrypted blocks. Until a first block of the plurality of encrypted blocks is received with error, a first keystream is generated (205) from the encryption synchronization and at least one of the plurality of encrypted blocks, and, using the first keystream, the plurality of encrypted blocks, received without error before the first block of the plurality of encrypted blocks is received with error, is decrypted (207). A priming block is determined (211) from the message. When the first block of the plurality of encrypted blocks is received with error, a second message is transmitted (219) requesting a retransmission of the first block. Upon receiving the retransmission of the first block without error, a second keystream is generated (223) from the priming block and the retransmission of the first block and decrypting the retransmission of the first block is decrypted (225) using the second keystream.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.