A push-based key distribution and rekeying protocol for secure multicasting

Abstract

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 have proposed an asynchronous rekeying framework based on the reliable and totally ordered multicast protocols (RTOMP). In our framework, a group consists of some domains which have some group members and one trusted key distribution server (KDS). The secure RTOMP channel is assumed for the communication channel among KDSs. 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. Each member has an individual key between the KDS in the domain. The member can take a new key from the KDS in its own domain. Although this approach can disperse the cost of key creation and distribution to all KDSs, each KDS is responsible to key distribution to all members in the domain. Therefore, the scalability is limited by the performance of the KDS. We introduce the push-based key distribution and propose the combined approach of pull-based and push-based key distribution. From our simulation, the proposed approach can reduce the cost of the KDSs and improve the scalability.