The Study, Based On Open Business Environment Of The P2p Network Model Of Trust Management

Uder the development of scale of the Internet and fast progress of inter-connection technologies, P2P network technology, which becomes a hot topic of computer science, eventually are used in many applications. P2P is the abbreviation of Peer-to-Peer, which is called peer network. Peer network is a tyoe of network model, in which model all the nodes are peer entities. The nodes, called as peer nodes, have the same capabilities and duties. The peer nodes can share resources through direct connections, without any control from any central server.P2P applications bring changes to the web based service environment. The service environment changes from a close, static mode to a open, public and highly dynamic mode. This kind of changes complicates the security analysis for web based applications. Security technologies for traditional softwares are no longer applicable to P2P applications. There is a requirement for new methods to solve these challenges.Trust management is a new technology to provide security framework in P2P service environment recently. But there are some problem unsolved during the research of this technology. Therefore, the aim of this thesis is to propose a set of trust management models, including certificate based authentication, trust model and trust negotiation model.The main innovations of the thesis are summarized as follows:The first part of the thesis summarizes and analyses the applications and security requirements of P2P technology. The thesis sort P2P network models and compare them with Client/Server network model. The applications of P2P technology is listed in the thesis. Then the thesis summarizes the security requirements of open service environment based on P2P network model.The second part introduces the concepts of trust management. Firstly the definition and model of trust management are given. Then the thesis analyses several representative trust management systems and trust evaluation models. At last the existing problems and the research directions of trust management.The third part studies the application of PKI in P2P network model. PKI can improve the security of P2P network model if the P2P environment can provide the capability of certificate authentication. After analysis of PKI trust model, a new method of automaticly creating and validating certificate paths is proposed.The forth part of the thesis studies the trust model. The thesis brings forward a entity-behavior based distributed trust model. This trust model uses the behavior of the entities in the network as feedback information, evaluates key attributes and class vectors, and calculates trust level of entities by proper algorithms. The model distributes entity behaviors information into all the entities in the network. The model also introduces amendatory factors and feedback system for evaluation veracity, which can effectively restrain cheatings.The fifth part studies trust negotiation technology. This part defines concept of trust negotiation and factors of trust negotiation. Then introduces formal description of trust negotiation policy, with the provement of its sufficiency and efficiency. Then a Petri-net based modeling method is proposed. The compare with modeling methods based on tree evolution shows that the new mdeling method has better performance.