摘要 |
A method to manage members of a group of decoders having access to broadcast data, each group member sharing a common broadcast encryption scheme (BES) comprising the steps of, in a stage for a decoder to become a group member, receiving keys pertaining to the position in the group according to the BES, receiving a current group access data comprising a current group access key, and in a stage of accessing broadcast data, using the current group access data to access the broadcast data, and in a stage of renewing the current group access key, sending a first group message comprising at least a net group access key encrypted so that only non revoked decoders can access it, said group message being further encrypted by the current group access key, updating the current group access key with the next group access key.
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