| 摘要 |
<p>A streaming system for encrypting and stream-delivering data, such as encrypted music and video and the like. A client terminal (30) used in this system forms a leaf of a hierarchical tree structure and has a key set comprising a root key on a path of this tree structure, a node key and its own leaf key. The client terminal receives an SDP file from a stream server (20). The SDP file contains encrypted information comprising EKB having data encrypted by a selection key possessed only by particular client terminals and further comprising encrypted content key data wherein a content key has been encrypted. Only particular client terminals (selected client terminals) having a selection key in their key sets decode the content key from the selection key, and also decode the stream-delivered encrypted content data into the content data to provide a real time reproduction.</p> |
