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Expired Canadian patentCanada

Enciphering/deciphering method and arrangement for performing the method

CA 1291801 C · Owner: N.V. Philips' Gloeilampenfabrieken · Inventors: Jansen, Cornelis J.A.

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Abstract From the Canadian patent

Enciphering/deciphering method and arrangement for performing the method.", The invention relates to a method of enciphering information-containing digital data signals with the aid of enciphering keys and of deciphering a message thus enciphered, utilizing the same key. For usages in which high demands are made on the quality of enciphering the conventional method - the EX-OR adding together of clear text and key text on a bit basis - has shortcomings. The invention has for its object to provide a very reliable method with which furthermore the propagation of errors caused by any transmission errors is prevented. This is accomplished in that the (clear) text characters to be enciphered are …

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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 November 5, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended November 5, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 6, 1987
GrantedNovember 5, 1991
Term endedNovember 5, 2008
Patent numberCA 1291801 C
Classification (IPC)H04L9/14 +1 more

Timeline

Timeline From CIPO dates

1988199119941997200020032006Application filedNov 6, 1987Patent grantedNov 5, 1991Term endedNov 5, 2008

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.