Incentive And Penalty Policies Based Research On Trust Mechanisms For P2P Networks

P2P networks are free, equal and open. The introduction of P2P technologies gives rise to a new web experience, but also brings about new network security issues. There are some security risks caused by irrational malicious nodes and a huge waste of network resources brought by rationally selfish nodes in P2P networks. How to implement a mechanism to promote the nodes to consciously regulate their behaviors, actively cooperate in good faith, share resources in good willing that we can build a reliable and harmonious network platform, is the major problem in researches on P2P networks management mechanisms.This thesis studies the patterns and game equilibrium of nodes’transactions and analyzes the formation mechanisms and implementation conditions of nodes’cooperative transactions. On this basis, we build a trust mechanism which incentive or punish the different behaviors of nodes in order to promote nodes to regulate their own behaviors in accordance with the desired cooperation strategy. In the mechanism, node’s overall credibility is computed by integrating its partial credibility and network contribution, and node’s intensity of incentives and penalties dynamically changes according to its different credit characteristics. The credibility calculating time is sliced by using time window which can demonstrate the time dimensions of credibility calculation, effectively response to join, leave, and malicious deception of nodes. The local credibility is calculated based on multi-dimensional evaluation factors which can fully reflect the influence and role of history transactions to the current transaction.We simulated a contrast between the trust model and other typical trust model, the results show that this model has been partially overcome the limitations of other models in some respects, has a good ability to adapt to the dynamics of the network. At the same time, the model can effectively curb the irrational behaviors of malicious nodes, encourage rational selfish nodes to contribute resources and improve the enthusiasm of nodes’honest trading and sharing resources.