APPARATUS FOR MANAGING MEMBERS OF AT LEAST ONE GROUP OF DECODERS HAVING ACCESS TO BROADCAST DATA

摘要

A technique 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 lease a next 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.

主权项

1. A management system for managing a population of decoders having access to broadcasted data, each decoder being temporarily assigned to a position in a group of decoders and sharing a common broadcast encryption scheme, the management system being adapted to: revoke at least one decoder from the group;
declare the position of the revoked decoder as vacated; renew a current group access key for the group using a global group addressed message comprising at least a next group access key encrypted using the broadcast encryption scheme so that only the decoders corresponding to non-revoked positions can decrypt it, whereby the at least one revoked decoder is incapable of correctly decrypting the global group addressed message, said group message being further encrypted by the current group access key; and reuse a position vacated by a revoked decoder by making said next group access key the current group access key.