Quantum cryptography
CA 2196556 C · Owner: Townsend, Paul David · Inventors: Townsend, Paul David
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a method of communication using quantum cryptography single-photon signals , from a highly attenuated source are modulated and subsequently detected. In the step of detecting the modulated signal the signal is split between two , branches according to its encoded state. Signals corresponding to different encoded states are detected independently in the respective branches and the rate of detection of coincident signals is determined. This rate is compared with a threshold to detect the presence of an eavesdropper.
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 August 16, 1995 and granted April 11, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 16, 2015.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 16, 2017.
- 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.