Trustworthiness-based Approach to Reliably Make Agreement among Peers in Scalable P2P Group

Information systems are being shifted to scalable architectures like Cloud and peer-to-peer (P2P) models. In this paper, we consider the P2P model as a fully distributed, scalable system different from centralized coordination systems in Cloud and Grid systems. A P2P system is composed of peer processes (peers). Here, applications are realized by activities and cooperations among multiple peers. In P2P systems, since there is no centralized coordination, each peer has to obtain information about others by itself. In the group activities, each group member has to be trustworthy so that malicious action of an individual peer cannot effect overall outcome of the whole group. It is important to consider the trustworthiness of each group member as a base of an agreement procedure in the distributed environment. The goal of the group and the way to archive the goal are decided by the group members. During the agreement procedure, opinion of each group member has to be considered. Malicious and unexpected behaviors of member peers can negatively effect the output of a group. Hence, it is significant to discuss how to compose a group only by including more trustworthy peers. In this paper, by taking advantage of the trustworthiness concept of each peer, we propose a novel approach to composing a trustworthy group in the distributed agreement protocols.