FTKM: A fault-tolerant key management protocol for multicast communications

Several protocols have been proposed to deal with the group key management problem. Unfortunately, most of these protocols lack fault-tolerance. This is a serious drawback in real network conditions, especially, when considering asynchronous wide-area networks, such as the Internet, where messages may be delayed indefinitely and nodes may fail. To cope with this limitation, failure detection/correction mechanisms are necessary. This kind of solutions introduces a new challenge, which is the requirement of periodically exchanging failure information between group members. This is a heavy communication overhead even with small groups. To avoid the periodic broadcast of failure information, we propose in this paper a solution that structures group members into a logical ring where only pair-wise communications are necessary to detect failures. Compared to other schemes, our solution is efficient and fault-tolerant.