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:
Jul. 26, 2011
Filed:
Jul. 06, 2006
Philippe Stransky, Cheseaux-sur-Lausanne, CH;
Philippe Stransky, Cheseaux-sur-Lausanne, CH;
Nagravision S.A., Cheseaux-Sur-Lausanne, CH;
Abstract
The invention concerns a method for controlling access to encrypted data (CT) by control words (CW), said control words being received by a security module in control messages (ECM) and returned to a unit operating on the encrypted data. Said control messages (ECM) contain at least one first control word (CW) and a second control word (CW), said control words each allowing access to the encrypted data (CT) during a predetermined period called cryptoperiod (CP). Said method includes the following steps: sending said encrypted data to at least one operating unit; and sending control messages (ECM) to said control unit, such a control message (ECM) containing at least two specific control words (CW, CW) being sent to the operating unit after sending the data encrypted by said first control word (CW) and before sending the data encrypted by said second control word (CW). Said method is characterized in that the time shift between sending to the operating unit the data encrypted by said first control word (CW) and sending the control message (ECM) containing said first control word (CW) and said second control word (CW) is more than 75% of the cryptoperiod.