Broadcasting encrypted signals
CA 1209664 A · Owner: British Telecommunications Public Limited Company · Inventors: Serpell, Stephen C.; Gordon, John A.; Brookson, Charles B.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Binary signals for broadcasting are encrypted by a pseudorandom bit-stream generated from a secret key and an initialisation bit-stream. The initialisation stream is multiplexed, broadcast, recovered at the receiver and used to regenerate the pseudorandom stream for decrypting. The multiplexing ensures synchronisation. Each pseudorandomiser at transmitter and, receiver, has a ciphering engine containing the key. 64-bit words are pseudorandomised and fed back from the output register and the pseudorandomised words are sent bit-by-bit on line as the encryption stream. The random number generator produces an initialisation stream which is formed into words by initialisation register and …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted August 12, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 12, 2003.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.