Study On Trust Computing Based On Social Network In P2P Services Environments

P2P network is a kind of dynamic,open and distributed services environment.It aims at large scale collaboration computation and resource sharing by making full use of all terminal systems in Interact.But,there some different degree of threats and attacks in interactions between peers will happen.They do not trust each other because of their characteristics of autonomy and spontaneity.The traditional technologies for security are not reliabile because they depend on the right operations of peers,and can not deal with the trust and incentive issues among cooperative anonymious peers in Interact.Recently,the trust model is becoming a hotspot of network security research.The research of trust provides the ideal technology to solve the security issues in P2P network. The trust model can forecast the behavior of peers by evaluating trustworthiness of peers or resources,and then encourage good behavior of peers and prevent bad behaviors of them. However,there are a lot of problems to be solved,such as the reasonably formalizing the trust, building and propagating the trust in distributed environment and finding the trust path,etc.In this thesis,we redefine the trust based on the social network by analyzing the researches of sociology,economics,psychology and informatics.We propose a trust framework for P2P network security and the system of evaluating,building,propagating, maintaining and validating based on the characters of P2P service environment and its development tendency.(1) We briefly overview the characteristic of P2P service environment and the security issues,and expatiate the research of trust in social network and the advantage of trust to solve the security problem in P2P network.Then,we introduce the significance,content,the main innovation and the contracture of our research.(2) We propose architecture of trust computing based on the demand of P2P service environment and the comprehensive analysis of trust models provided by some researchers. The trust computing reflects the characteristic of dynamicc and self-adjusting,Therefore,we make definitude of the research of trust computing.(3) We propose a security framework based on trust computing of P2P network.And,we detailly describe the functions of each module of the framework.(4) We make the dynamics analysis of trust by evolution game based on the evolution of ecological and social network.Then,we provide the theory of trust dynamics and ecological evolution of network.Furthermore,we deeply study the dynamics equations of trust and the evolution tendency of trust relationship among peers by replicator dynamics,and find the evolution law of the trust dynamics and the evolution stability of the network ecology.(5) We give an evaluation mechanism of dynamic trust based on the continuous updating and propagating of the trust among persons in social network.And,we propose an incentive model based on the control mechanism of energy in ecological network.With the application of those models,the network security can be enhanced and the service efficiency can be improved.(6) Based on the aware computing and the model of epidemics propagation,we analyze the propagation mechanism of trust in distributed networks by dynamics.This work is the foundation of safeguarding the network security,improving the cooperation among peers,and promoting the evolution of open network from out-of-order to order and from noncooperation to cooperation.(7) We propose a pyramidal model of trust management based on the model of Jin-Sou-Quan-Ceng in social network.First,we design the algorithms of node clustering based small world and formation of pyramid.By applying these algorithms,we get a topology which resembles the hybrid P2P.Those peers on the top of pyramid resemble the super-peer as managers of network.Therefore,this model takes advantage of centralized and entirely distributed structure of P2P topology.It is an efficient application model to apply in the network for security issues.Finally,we summarize the researches of this thesis,and propose the next work in the future.The framework,methods and models for trust computing based on the social network presented in this thesis enrich the research of trust model,and provide some novel concepts and methods for network security.The presented trust computing system not only provides a good project to apply in P2P service environment for enhancing the security,but also grows into a network middleware which can be embedded into the current Internet network architecture to promote the efficiency and quality of network services.