A novel multi-level trust model to improve the security of P2P networks

Peer-to-peer (P2P) network provides an efficient way for resource sharing. However, due to lacking centralized control and the anonymity of peers, security becomes a serious problem in P2P network, especially in P2P file-sharing network, which heavily restricts the development of P2P file-sharing systems. Trust models have been widely used in estimating the trustworthiness of peers in P2P file-sharing systems in order to minimize threats of such open communities. However, current P2P trust models almost measure whether a peer is good or bad only by a trust value, which results in low efficiency in resisting the attacks of malicious peers. Additionally, there are more and more free-riders in P2P systems. This paper proposes a new trust model based on a 5-tuple to deal with these two problems, which integrate the set of uses, trust, experience, sharing files and heterogeneity levels. The simulation experiments are carried out to evaluate the performance and validity of this trust model in a P2P file-sharing system. The result proves that it is effective to prevent malicious act and encourage peers to share there resources in P2P network.