Public key/signature cryptosystem with enhanced digital signature certification
CA 2000400 C · Owner: Fischer, Addison · Inventors: Fischer, Addison
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A public key cryptographic system is disclosed with enhanced digital signature certification which authenticates the identity of the public key holder. A hierarchy of nested certifications and signatures are employed which indicate the authority and responsibility levels of the individual whose signature is being certified. The certifier in constructing a certificate generates a special message that includes fields identifying the public key which is being certified, and the name of the certifiee. The certificate is constructed by the certifier to define the authority which is being granted and which may relate to a wide range of authorizations, delegation responsibilities or restrictions …
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 October 10, 1989 and granted October 8, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 10, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 10, 2011.
- 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.