Method and apparatus for encrypting and decrypting time domain signals
CA 2024641 C · Owner: Ryan, John O. · Inventors: Ryan, John O.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A technique for encrypting and decrypting information signals normally arranged as a succession of lines of active information, with each line having a line timing reference, such as color video information signals. Active video portion is time shifted with respect to the horizontal sync portion of the corresponding line using a predetermined slowly varying time shifting function. The time shifting information is conveyed to the decryption site by encoding the instantaneous value of the time shifting wave form for the beginning of each field in the vertical blanking portion of that field. To provide a reasonable maximum time shifting range, portions of the trailing edge of the active video …
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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
- Filed September 5, 1990 and granted December 5, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 5, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 5, 2012.
- 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.