Decentralized group key management for secure multicast communications

Multicast protocols provide mechanisms for a sender to send a message to multiple receivers simultaneously. When the multicast message is of a sensitive nature, it should be encrypted. This would require that all the members of the multicast group share the same encryption key. In this paper, we present a simple and scaleable method to create and distribute symmetric cryptographic keys amongst a group of communicating network users for multicast communications. The group symmetric keys permit each user to conveniently and securely communicate, share and access data belonging to the multicast group. Unlike current group key-management mechanisms, this scheme does not involve the use of a centralized key distribution center-only the group members generate and distribute group symmetric keys. Once a long-term group key has been established among a group of communicating peers, the scheme provides an easy way for any group member to send secure messages to all other group members without having to send the session key individually to each group member. Moreover, the scheme provides an option for allowing data traffic to be authenticated on a per-sender basis with sender-specific keys. (C) 1999 Elsevier Science B.V. All rights reserved.