The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 03, 2009
Filed:
Apr. 23, 2004
Rached Ksontini, Lausanne, CH;
Henri Kudelski, Grandvaux, CH;
Cédric Groux, Chexbres, CH;
NagraCard S.A., Cheseaux-sur-Lausanne, CH;
Abstract
A method is for protecting an encrypted content, by use of at least one encryption key. The method includes generation of a temporary encryption key, encryption by the temporary key of a value allowing the determination of the encryption keys of the content, transmission of the encrypted value to a multimedia unit, and encryption and transmission of at least two cryptograms including the temporary key encrypted by an authorization key. The first cryptogram is encrypted by a first authorization key pertaining to a first security module and the second cryptogram is encrypted by a second authorization key pertaining to a group of security modules whose first security module is excluded.