DUAL ENCRYPTION PROTOCOL FOR SCALABLE SECURE GROUP COMMUNICATION

摘要

A logical tree structure (10) and method for managing membership in a multicast group provides scalability and security from internal attacks. The structure defines key groups (20) and subgroups (24, 22), with each subgroup having a subgroup manager (12, 14, 18). Dual encryption allows the sender (12) of the multicast data to manage distribution of a first set of encryption keys whereas the individual subgroup managers (12, 14, 18) manage the distribution of a second set of encryption keys. The two key sets allow the sender (12) to delegate much of the group management responsibilities without compromising security because a key from each set is required to access the multicast data. Security is further maintained via a method in which subgroup managers (12, 14, 18) can be either members (18) or participants (14). Access to both keys is provided to members (18) whereas access to only one key is provided to participants (14). Nodes can be added without generating a new encryption key at the top level which provides improved scalability.