Estimation of Trustworthiness for P2P System in Collusive Attack

In the community of P2P, it is paid attention to try to control illegal behavior of the peer by managing the reputation of the peer. However, the implementation overhead was large, and the semantics of the trust model was indefinite in many of proposed methods. On the other hand, the trustworthiness estimation method by a simple, probabilistic technique, that is, by the maximum likelihood estimation is proposed. If this method is used, the problem concerning the semantics of the reliability model and the problem of the implementation overhead can be improved. However, the defense to a collusive attack is not proposed in this method. In this paper, it proposes the trust estimation method of the peer to give the defense to a collusive attack to the maximum likelihood estimation method. Moreover, peer´s trustworthiness is correctly estimated though there is a collusive attack in this proposal method from the simulation result