Patent ID: 7693281

Claim:
A method of distributing individual keys for deciphering scrambled digital content data transmitted by a broadcasting system including several terminals connected to a data exchange network, the broadcasting system having at least one portal to provide the individual keys, at least one scrambling platform and at least one server to broadcast the scrambled data, comprising: dividing a scrambling period of the digital content data transmitted into a succession of encoding periods CP i , CP i+1 , CP i+2 , each defining a period of validity of an individual deciphering key K i , K i+1 , K i+2 , supplying, at each connection of a terminal to the portal, a set of individual keys comprising at least one key corresponding to the encoding period CP i , and at least one key corresponding to the encoding period CP i+1 ; planning, during a given encoding period CP i , during which a plurality of terminals connect to the portal, the distribution during the next encoding period CP i+1 of dates of future connection for the plurality of terminals connected to the portal taking into account new connection(s) or disconnection(s) of terminal(s) as necessary; and supplying, at each connection of a terminal to the portal during said given encoding period CP i , a set of individual keys comprising at least one key K i corresponding to the current encoding period CP i , and at least one key corresponding to the next encoding period CP i+1 , the planned date of future connection of said terminal to the portal during the next encoding period CP i+1 in order to collect a set of deciphering keys corresponding to at least one future encoding period CP i+2 , wherein the duration of an encoding period is permanently compared to a threshold value CP max , and in that an alarm signal is generated by the portal when the encoding period reaches a duration equal to CP max .