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:
Mar. 15, 2011
Filed:
Jul. 06, 2006
Henri Kudelski, Grandvaux, CH;
Jimmy Cochard, Attalens, CH;
Henri Kudelski, Grandvaux, CH;
Jimmy Cochard, Attalens, CH;
NagraCard S.A., Cheseaux-sur-Lausanne, CH;
Abstract
The invention concerns a method for controlling access to encrypted data by control words (CW), said control words being received by a security module in control messages (ECM) and returned to a unit operating on (STB) the encrypted data. The method includes the following steps: receiving a first control message (ECM) comprising at least one control word (CW) and a time stamp (TS), receiving a second control message (ECM) consecutive to the first control message (ECM), said second message comprising at least one control word (CW) and a time stamp (TS), determining a duration corresponding to the difference between the time stamps (TS) of the two consecutive control messages (ECM, ECM), if said duration is less than a predefined duration (CP), incrementing an error counter (CE), and if said duration is not less than said predefined duration, decrementing said error counter (CE), returning the control word (CW) to the operating unit (STB) after a waiting time depending on the value of the error counter (CE).