Abstract: A great deal of malicious behaviors makes it hard to support validity and availability in the mobile P2P networks.Most of current peer-to-peer trust models are applicable to fixed network，neglect the effect of different terminals，and could not promise the trust computation of different domains.This paper presents a trust mechanism，Multiple Granularity Trust Model（MGT），which imports the clustering and time factor，then gives the implementation of the MGT source selection protocol.Emulating experiment shows that MGT is more effective on protecting the network from many malicious behaviors and more robust on trust security problems.

摘要： 移动P2P网络的应用越来越广泛，随之而来的是大量欺诈等恶意行为，使系统的有效性和可用性难以保证。现有模型大多针对固定网络，忽略了终端类型对节点信任值的影响，而且不能很好地解决节点在不同领域、不同方面的可信度计算问题。针对上述问题，利用聚类思想和时间因子的概念，提出一种多粒度信任模型MGT（Multiple Granularity Trust Model），并给出基于该模型的资源选择协议的工作流程。分析结果表明，模型能够有效地抵御恶意节点的破坏，增强P2P网络的安全性。