| 摘要 |
<p>The present invention aims at proposing a method allowing a versatile management of a group of decoders, this group having conditional access to audio/video content. Accordingly, it is proposed a method to manage members of at least one group of decoders having access to audio/video data, each group member having the status of non-revoked or revoked member, and sharing a common broadcast encryption scheme allowing to revoke at least one member of the group by sending a group addressed message, comprising the steps of: In a stage for a decoder to become member of the group:
- receiving and storing the keys pertaining to the position into the group according to the broadcast encryption scheme,
- receiving and storing a current group access data (CGD) comprising at least a current group access key (CGK) common to said group, In a stage of accessing audio/video data :
- using the current group access data (CGD) to directly or indirectly access to the audio/video data, In a stage of renewing the current group access key (CGK):
- sending a first group message comprising at least a next group access data (NGAD) comprising at least a next group access key (NGAK) encrypted so that only the non-revoked decoders can access to it, said group message being further encrypted by the current group access key (CGK),
- updating the current group access key with the next group access key.</p> |
