Document copying deterrent method
CA 2136166 C · Owner: American Telephone And Telegraph Company · Inventors: Brassil, John Thomas; O'Gorman, Lawrence Patrick; Maxemchuk, Nicholas Frank
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention is directed to a method of deterring the illicit copying of electronically published documents. It includes utilizing a computer system to electronically publish a plurality of copies of a document having electronically created material thereon for distribution to a plurality of subscribers and operating programming within the computer system so as to perform the identification code functions. The steps are to encode the plurality of copies each with a separate unique, identification code, the identification code being based on a unique arrangement of the electronically created material on each such copy; and, creating a codebook to correlate each such identification …
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
- Filed November 18, 1994 and granted June 29, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 18, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 18, 2016.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
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.