Abstract: This paper presents a novel trust evaluation mechanism for P2P system based on the trade characteristics and transaction feedback. In order to evaluate the validity of feedback, this paper adds time-decay factor and transaction factor into P2P trust model, and the model’s calculation method of reliability is also introduced. The simulation experimental results show that the evaluation mechanism can improve calculation accuracy of local reputation and global reputation, and inhibit bad nodes effectively. The performance of this model is superior to PeerTrust and EigenTrust model, the proposed trust mechanism can be applied to P2P system effectively.

Key words: Peer-to-Peer（P2P） system, reputation, trust mechanism, trust level, time decay

摘要： 提出了一种新的在P2P系统中基于交易特征和反馈评价的信任评估机制。为确定反馈评价的真实性，模型引入了时间衰减函数和事务影响参数，给出了反馈评价的可信度计算方法。实验仿真结果表明，该评估机制能够提高局部声誉和全局声誉的计算准确性，有效地抑制恶意节点。与信任模型PeerTrust和EigenTrust相比，该模型的性能优于其他两者，能够更好地应用于P2P电子商务系统中。

关键词: 对等网络, 声誉, 信任机制, 信任度, 时间衰减