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:
Oct. 01, 2013
Filed:
Mar. 13, 2009
Pascal Junod, Vufflens-la-Ville, CH;
Alexandre Karlov, Meyrin, CH;
Nicolas Fischer, Versoix, CH;
Nagravision S.A., Cheseaux-sur-Lausanne, CH;
Abstract
The present invention makes use of techniques such as those described by Boneh and Franklin to allow for the realization of a pseudo-asymmetric encryption scheme whereby one public encryption corresponds to a plurality of private decryption keys. This scheme therefore provides a solution to the problem of inefficient use of bandwidth in asymmetrical encryption schemes which inherently require that a plurality of encryptions of data be broadcast to a plurality of receivers. The invention further ensures that the advantage of traceability, typical found in asymmetric encryption schemes, is maintained due to the characteristic that each receiver uses a unique traceable decryption key. The traceability thus achieved by the present invention allows for the revocation of a security module which has been involved in the abusive use of conditional access data, particularly by means of clones of security modules whose security has been compromised.