Secure group communication protocol for distributed systems

In distributed applications like groupware, group communication among multiple entities is required. The local area networks (LANs) and radio networks provide broadcast communication at the media access control (MAC) layer, that is, every entity can receive every protocol data unit (PDU) transmitted in the network. Group communication among multiple entities can be easily realized by these networks. One problem in the broadcast network is how to provide secure communication for the group. In this paper, we discuss how to provide secure group communication in the presence of attacks by malicious entities. The protocol is based on the distributed control scheme by using less-secure broadcast networks. A group of entities is named a cluster. By the protocol, only and all the entities in the cluster can agree on a same secret key by exchanging the nonce enciphered by the public key. A subset of the cluster may require such secure communication that the other entities in the cluster cannot join the communication. In this paper, we discuss how to establish the secure subcluster communication in the cluster