| 摘要 |
Managing group membership of receivers-in-broadcast and multicast content distribution systems. The invention provides for security in group communications where a single source is broadcasting or multicasting to multiple destination points on a network such as the Internet using a local agent resident on a user system, an authorization token, and a trusted group manager (TGM) representing a content distributor. The local agent may be tamper resistant code providing support for key agreement, decryption, and message authentication functions. The authorization token describes which agents are active and available to decrypt digital content or a per packet basis. The TGM establishes a session key with a group of local agents and generates authorization tokens. The local agent adds and removes itself from a content distribution session (and associated group) based on a series of protocols that do not require a "re-key" for an encrypted content stream being broadcast or multicast by a content distributor. The protocols include operations for registering with a group, joining a group, and leaving a group. |
