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. 01, 2011
Filed:
Jun. 10, 2002
Odile Derouet, Montrouge, FR;
Odile Derouet, Montrouge, FR;
Nagra Thomson Licensing, Boulogne-Billancourt, FR;
Abstract
An access control method is described for an encrypted program transmitted by an operator to a plurality of groups of subscribers, where each group of subscribers has a group key KG, and each subscriber is able to receive from the operator an operating key KT, enciphered by the group key KG for decryption of the transmitted program. The method further involves linking the enciphered operating key KT to a random value R to generate a secret code, transmitting the secret code to subscribers prior to transmission of the encrypted program, and transmitting the random value R to subscribers for calculation of the operating key KT.