Key signal encryption and distribution system for controlling scrambling and selective, remote descrambling of television signals
CA 1264848 C · Owner: Cable/Home Communication Corp. · Inventors: Gilhousen, Klein S.; Newby, Charles F. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A system and method for scrambling and selectively descrambling television signals that are transmitted to subscribers' descramblers in a subscription television system. A working key signal is generated by processing an "initialization vector" signal in accordance with the DES algorithm upon the algorithm being keyed by either a common category key signal or some other key signal. A unique encryption keystream is generated by processing the initialization vector signal in accordance with the DES algorithm upon the algorithm being keyed by the working key signal. A television signal is scrambled in accordance with the unique encryption keystream to provide a scrambled television signal. A …
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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 January 23, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 23, 2007.
- 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.