Cascading dynamic crypto periods
US8687807B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 26, 2011 |
| Grant date | Apr 1, 2014 |
| Priority date | — |
| Expiry date | Dec 20, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2463/062
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.