A security policy based on bi-evaluations of trust and risk in P2P Systems

The recent and unprecedented surge of public interest in peer-to-peer (P2P) systems has led to a variety of interesting research questions. How to minimize threats in such an open community is an important research topic. Trust models have been widely used in estimating the trustworthiness of peers in P2P file-sharing systems where peers can transact with each other without prior experience. However, current P2P trust models almost take no consideration for the dynamic characteristic of trust, which results in low efficiency in resisting the attacks of malicious peers. In this paper, a new security policy that integrates aspects of trust and risk evaluations is proposed. We first introduce trust and risk evaluations for each transaction, and then apply them to control the access permission of transactions among peers in the network. Finally, simulation results prove that the security policy analyzed here thus stands against malicious act effectively.