The Research And Design Of Trust Mechanism In P2P

Compared with traditional C/S(Client/Server) network application mode, the P2P(Peer to Peer) network has the characteristics of extension, robustness, fault tolerance and self-determination etc. For the past few years, P2P network is widely applied in cooperative computation, distributed storage, and can be used in peer search. But P2P network is also existing some problems. The anonymity, activity, opening of P2P network lead to some security leak. They make the P2P network be affected by inbreak, fraud, network virus more easily. The basic assumption of P2P network is that peers are willing to share resources with others. In fact peers in the network consider how to maximize the personal utility without considering the whole network productivity which leads to the problem of free-riding. Considering of the specificity of P2P network, constructing trust mechanism is a key method of solving the problem. Based on the existing trust mechanism, this dissertation gives a new trust mechanism, and results in the following achievements: I. The trust mechanism designs an incentive measure of differentiating service, reciprocal capacity. The incentive measure is proved to be effective to encourage normal trade, restrain malicious trade.II. In P2P network peers take on different interesting groups, most trades occur among peers who are in the same group. We can not make uniform security mechanism because different interesting groups have distinct characteristics. This makes P2P network be attacked by malicious peers easily. This dissertation presents and designs a security mechanism which is based on group strategy. Group strategy is distinct with different interesting groups. In the group strategy of this paper's P2P file share system we use AES, ECC, etc advanced encryption algorithms to protect information's secrecy, integrality which enhance P2P network's security and stability.HI. Based on the idea of recent behaviors can reflect future behavior trend much better, we compute trust value with time factor to build an active trust model. It makes trust mechanism have a good activity to restrain cumulative reputation treachery and union fraud with front peer etc malicious attack.IV. Based on the JXTA platform, this dissertation programmes trust mechanism and a P2P share system. This dissertation uses the programme to construct a P2P network environment to test trust mechanism. The results prove that trust mechanism has the characteristics of affectivity, reasonable and good adaptability of network topology. It can enhance normal trades and restrain malicious attack.