METHODS AND BURST-TRANSMITTERS OF A PIECE OF ENCRYPTED MULTIMEDIA CONTENT, AND STORAGE MEDIUM FOR SAID METHODS

摘要

The invention relates to a method for the burst-transmission of a piece of encrypted multimedia content, in which the replacement (110) of a current encryption key TEKj  with another current key TEKj+i for encrypting a segment Pi of the piece of multimedia content is postponed until a moment tdi + TSTKM or advanced to or before a moment tdi in response to a synchronisation signal exchanged (82) between a burst generator and a synchroniser capable of replacing the current key at each cryptoperiod end, the duration TSTKM being higher than or equal to the time necessary for a receiver to decrypt a cryptogram of a current key contained in a burst S1 and strictly lower than a selected cryptoperiod duration T, the moment tdi corresponding to the beginning of the segment Pi.