The Research On P2P Network Security Based On Trust

Peer-to-Peer network has been a hot point in the field of international computer network over the past few years and it will become a key technology for the next generation network.As a new technology,it is still not mature and complete. Peer-to-Peer network not only involves conventional security problems in Client-Server network, but also faces a number of new challenges that are not typical in Client-Server network.The further development of P2P application partly will rely on the improvement of security in large-scare P2P network. Therefore, it is a necessary work to design a better Peer-to-Peer network security model. The trust management,as a new method of access control,can be applied to large-scale and distributed Peer-to-Peer application.This thesis contains details pertaining to the following aspects:Firstly,the current research situation of trust management at home and abroad is analyzed,including the existent problems.For example:In those distributed applications has taken trust management into account,some of them only focus on the calculation of trust relation,and the else only describe authorization relation.Most of actual search algorithm of authorization certificate chain premises that all authorization certificate will be found in one place,the principle of control in distributed network is disobeyed.Combining trust management with conventional security mechanism,a new security mechanism will be built and be provided to solve new security question.Secondly, aiming to the existent problem,we develop a security model that fix up of SPKI and PGP, with the function of each component module specifically designed. The model incorporates the encrypt technique of PGP, and employs the strength of both PGP and SPKI, to compensate for the deficiencies of each single model. This security model is applicable to large-scale and distributed Pee-to-Peer networking, and is characterized by better agility, extensibility, and security.The third, we propose an approach for computing the trust value among entities in P2P environment. This approach focuses on well defined dynamical updating in the calculation of the trust relationship among entities, taking into account of the dynamical nature of the trust relationship. Considering that the reliability decreases as the length of trust chain increases, the max length of trust chain is set to be three, which makes the algorithm a good approximation of real situations.