The incentive secure mechanism based on quality of service in P2P network

In order to overcome the disadvantages of appearing the free-rider phenomenon and security issues due to the characteristics of anonymity and voluntary contributions resources in P2P network, this article firstly proposes a new strategy that based on trust value and considers both the quality and the number of shared resources to avoid the phenomenon of free rider. In the new strategy, we can calculate the trust value of the files in accordance with the consumer nodes' trust values, obtain nodes' effective contribution values, and select the node that has bigger trust value as service provider node. Moreover, the network can be divided into several regions according to the physical distances between nodes in the network. The nodes locating nearer are allocated the same region that is called cluster. In every cluster, we can select several nodes that have good physical properties and stability as management node to store and process all the information in the cluster and communicate with other management nodes in other clusters. In order to reduce overhead of network communication, encourage the nodes to make more transactions in the same cluster. Simulations prove that this strategy can guarantee the quality of service as well as restrain free-rider phenomenon, so as to enhance the utilization of resources and the success rate of transaction.