| 摘要 |
<p>A license server providing a key for decoding a content allocates a leaf of a key management hierarchical tree structure to a client, generates a set of node keys as a device node key and transmits it together with a leaf ID, a client secret key, and the like to the client. By making an intermediate node in the hierarchical structure a summit and making nodes below the summit node the related nodes of the category defined by the summit node, a manufacturer and a content provider managing the summit node of the category can generate a validation key block with that node as a summit and deliver it to the devices below the summit node. Thus, it is possible to update a key without affecting devices belonging to other categories.</p> |
