Research On Trust Mechanism Of Peer-To-Peer Networks

Peer-to-Peer network (Peer-to-Peer, referred to as P2P) is a distributed network with the advantage of self-organization, scalability, fault tolerance and load balancing, etc.,which has been widely used on file sharing, distributed computing, e-commerce and other fields recent years.But the anonymity and the openness characteristic of P2P network itself easily cause malicious acts of nodes within the network,such as spreading the virus, providing false documents which seriously affect the security of P2P networks.Currently,the utilization of trust mechanisms for solving security issues has been a research focus. The introduction of the trust mechanism can partly improve the security of P2P networks and beneficial to well development of P2P networks.However,this is likely to cause hotpot issues. In addition, in present trust mechanisms excessive computing and communications overheads is also a problem can not be ignored.According to the issues above,this paper propose a load balancing trust model based on Chord.The model computes the trust value of a node based on the information of its trade history in order to avoid the excessive overhead caused by iteration through the whole network. The trust value of a node is stored in its index node,and its index node is responsible for the storage,management and maintenance of trust information.It uses hash computping to locate index node when querying trust information and finds the index node by Chord protocol making the overheah of query lower.Meanwhile the model marks grades of nodes with trust value of nodes, load condition and communication delay and chooses node with the highest grade to trade with.When hotpot resources appear in the network,the model creates duplication dynamically to share load.The model revokes part of the duplication when request frequency of hotpot resources decreases so as to avoid hotpot issues and ensure excellent running condition of P2P networks.The model simulation results show that when malicious nodes in the network is over 10% or the access only concentrate on only 10% resources of the system,it obviously improves the success rate of transactions and enhance the reliability of P2P networks.