Securing dynamic group membership information over multicast: attacks and immunization

In secure multicast communications, key management is employed to prevent unauthorized access to the multicast content. Key management, however, can disclose the information about the dynamics of the group membership to inside attackers, which is a potential threat to many multicast applications. In this paper, we investigated several attack strategies for stealing group dynamic information and demonstrated their effectiveness through simulations. Further, we proposed an anti-attack technique utilizing batch rekeying and phantom users, and derived performance criteria describing the security level of the proposed scheme. The proposed anti-attack scheme was evaluated based on the membership data obtained from real MBone sessions.