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:
Apr. 01, 2014
Filed:
Jan. 26, 2011
Gregory Duval, Highlands Ranch, CO (US);
Henri Kudelski, Chexbres, CH;
Gregory Duval, Highlands Ranch, CO (US);
Henri Kudelski, Chexbres, CH;
Nagrastar, L.L.C., Englewood, CO (US);
Abstract
Systems and methods for performing cascading dynamic crypto periods are disclosed. In embodiments, a control word and a set of functions is transmitted between a head-end and recipient devices at the beginning of a crypto period. The crypto period is divided into a discrete number of sub-crypto periods. The control word used to encrypt and decrypt the broadcast content is changed during each sub-crypto period. At the end of the first sub-crypto period, a derived control word is generated by passing the original control word to a function in the set of functions in order to generate a derived control word at the first transition between sub-crypto periods. The derived control word is used for encryption and decryption of the broadcasted content during the second sub-crypto period. Upon transitioning to the third sub-control-period, the derived control word is input into another function to produce a second derived control word.