关键词: 对等网，信任，风险度，风险评佑

Abstract: As a result of P2P network being open and dynamic, it is inevitable that peers' information exchange brings security issues to systems. A trust based approach was introduced in risk assessment, and a risk assessment method was put forword by combining trust estimation with the traditional risk calculation to evaluate the risk of information exchange between peers. Risk value is derived from estimation of trust risk and result risk. Trust risk is estimated according to the long-term behavior of a node, and reflects the relationship between trust and risk. Result risk is estimated according to the short-term behavior of a node. Simulation results show that the risk assessment approach based on trust can effectively work in P2P network.

Key words: Pccr-to-pccr network, Trust, Risk, Risk assessment