A key distribution and rekeying framework with totally ordered multicast protocols

Many network applications based on a group communications model have been developed. As a remit securing group communications, i.e., providing confidentiality, authenticity and integrity of messages delivered between group members, will become a critical networking issue. We present a novel solution to the problem of scalable group key management. For the rekeying of the group key, all members of the group should agree the rekeying of the key. However, synchronization with all members for agreement of the rekeying is very costly. We propose the asynchronous rekeying framework based on the reliable and totally ordered multicast protocols (RTOMP). In our framework, a group is consists of some domains which has some group members and one trusted key distribution server (KDS). When the membership of a domain is changed, the KDS of the domain creates the group key and distributes to the all other KDSs via the secure multicast channel on its own responsibility. The KDS also sends the group key which is encrypted by the individual key to all new members of the domain. Therefore, the cost of the creation and distribution of the group key is dispersed over the all KDSs. From our simulations, the group key managed at the KDS is reasonable and scalability is improved even if the ratio of the key change is high.