| Today, P2P technology has been widely applied in all aspects of networks, the individual credibility has become a focus of trust model study. Traditional network security mechanisms, such as digital signatures and digital watermarking, can ensure the confidentiality and integrity of the transaction, but they cannot evaluate the trust of both transaction sides. Hence, the trust mechanism based on P2P can enhance system reliability.Through the analysis on the advantages and disadvantages of the existing trust model, we propose a SNTrust P2P network trust model. Using the concept of group, Nodes of each group are separated into super-nodes and normal nodes. Super-nodes are responsible for connecting all the normal nodes in this group, storing the whole trust of each node in the group. P2P network is formed among super-nodes. Normal node must pass through the corresponding super-nodes to join the P2P network, and the direct transaction data are stored locally in order to provide effect protection for the P2P network transactions.This model improves the previous methods of trust calculation in trust models and extends the scope of trust to (-1,1). In terms of cluster, trust calculation falls into two levels: local trust in the cluster and whole trust based on cluster.The node trust in the cluster is calculated by direct trust, indirect trust (which constitute final trust) and whole trust. Direct trust is attained from the ratio of historical success / failure records on the interactions between consumption node and service node,the failed deal is adjusted with the penalty factor; Indirect trust is obtained through integrating recommendation trust and whole trust. Recommendation trust, not affected by penalty factor, refers directly to the rates of transaction failure and success.Whole trust based on cluster is judged by the least value of whole credit worthiness of the two nodes involved in the transaction and direct transaction credit worthiness of the cluster in which the two nodes are included.The experiment, comparing the ratio of successful transaction in various volumes, demonstrates that this trust model is effective in restraining the behavior of malicious nodes and improving network performance. At the same time, the performance analysis on several other trust models further proves the feasibility and effectiveness of this model. |
