| 摘要 |
The invention concerns a method for distributing individual decryption keys for decrypting scrambled digital data transmitted by a broadcasting system to a plurality of terminals connected to a data exchange network (2), said broadcasting system comprising a portal (14) designed to provide the individual keys, at least a scrambling platform (16) and at least a server (6) for broadcasting the scrambled data. The invention is characterized in that said method comprises the following steps: breaking down the scrambling period of the transmitted data into a series of crypto-periods CP<sb>i</sb> each defining a validity duration of an individual key Ki, and each time a terminal (4) is connected to the portal (14), in delivering to said terminal (4) a set of individual keys comprising at least a key corresponding to the crypto-period CP<sb>i</sb> and at least a key corresponding to the crypto-period CP<sb>i+1</sb> and the date of a subsequent connection for recovering a set of decryption keys corresponding at least to a subsequent crypto-period if continued access is granted.
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