| 摘要 |
A license server offering a content decryption key assigns leaves of a key-managed hierarchical tree structure to clients, and generates a set of node keys as a device node key for transmission to each client together with a leaf ID and a private key of the client in question. When an intermediate node of the tree structure is deemed to be the top, all nodes subordinate to the top are established as nodes related to a category defined for the top node. In this setup, a manufacturer, a content provider, or like entity managing the top node assigned the category generates uniquely an enabling key block that defines the node in question as the top, and distributes the enabling key block to devices belonging to nodes subordinate to the top node. The scheme allows the managing entity to renew the key without affecting devices belonging to any other category. |
