Research On The Key Technologies Of Peer-To-Peer Network

The traditional client/server(C/S) network architecture suffers the shortcomings including the server performance bottleneck and the failure of single point, and the appearance of peer-to-peer(P2P) network make up those weak points. In the past few years, the P2P network has been rapidly developed by virtue of open, anonymity, expandability and server performance without restriction, and the technologies of P2P network have been applied to more and more areas. However, there are still many issues on P2P network, such malicious nodes proliferation, resource discovery inefficiency, node load imbalance and node lack of authentication are still obstacles in the course of P2P network forward. To improve the overall performance of P2P network, it is necessary to study the key technologies of P2P network and solve the critical problems. This paper investigates the key technologies of P2P network, and the main research results are as follows:1,Research on risk-aware P2P network security trust models.To build an efficient, scalable, and security trust model in P2P network, the P2P trust models are studied and a risk-aware P2P trust model is built. This model constructs a new relationship model between risk and reputation, and interlards recommendation reputation with risk. By means of the new risk evaluation function and the computation of probability model in series, the risk brought by direct exchange and indirect recommendation is well quantified. To avoid slander or coordinated cheat attack among malicious nodes, this model filters the local recommendation reputation and local recommendation risk with the center deviation method. Through P2P network simulation experiments and analysis, we find the performance gains brought by this model are significant and the system security is greatly improved. 2,Research on efficient algorithms for resource discovery in unstructured P2P network. To improve the efficiency of resource discovery in unstructured P2P network, the technologies of resource discovery in unstructured P2P network are investigated, and a routing algorithm employing multi-search information for integrated decision-making guide is proposed. This algorithm uses neighbor resource information indexing mechanism, broadens search horizons, and improves the probability of resource discovery. By means of dynamic time-to-live (TTL) mechanism, this algorithm sets TTL value flexibly, makes every effort to search, and increases the efficiency of resource discovery. Using variable routing information indexing mechanism and color management of index credibility, this algorithm distributes the layout of index in the various regions, enhances the credibility of the index, and improves the effectiveness for the index to guide the routing. Through P2P network simulation experiments and analysis, we find the performance gains brought by this algorithm are significant and the efficiency of resource discovery is greatly improved.3,Research on self-adaptive load balancing algorithms in unstructured P2P network. Search algorithms greedy, node itself heterogeneity and user query behavior uneven in unstructured P2P network lead to some nodes in a serious overload status. In order to solve the node load balancing in unstructured P2P network and optimize network topology, the technologies of load balancing for unstructured P2P network are investigated, and an adaptive load balancing algorithm in unstructured P2P network is proposed. The algorithm uses a steady-state load transfer method to achieve the forwarding load steady-state transfer from the overloaded node to the lighted node, makes link status and node status in steady state, and achieves the positive interaction cycle network ultimately. Meanwhile, in order to solve hot spots paper issues caused by uneven user queries, the algorithm uses the dynamic node caching mechanism based on capabilities, dynamically deploys and adjusts the hot files index density around the neighborhood node according to the heat of files, redirects a certain number of queries to the node according to the ability of node which owes a copy of the hot spots paper. Experimental results show that the proposed algorithm can achieve traffic load balancing of the node forwarding load and response load.4,Research on distributed denial-of-service (DDoS) defense technologies in secure P2P network. Malicious peer nodes launch DDoS attacks on the key routing node, make it not properly route messages to other nodes, and seriously disrupt the normal orders of P2P network. In order to construct secure P2P network environment, DDoS defense technologies are studied, and two algorithms based on dynamic probabilistic packet marking (PPM) are proposed. Our proposed algorithms enchance the performance of PPM in following aspects:First, because of ingenious design, our proposals can be used to tackle large-scale DDoS. Second, due to adopting dynamic probabilistic packet marking, our algorithms can recongnize and eliminate spoofed marking inscribed by the attacker intentionally. Third, by recording the state of IP address transmission in router and transmiting the packtes fragments in order, our algorithms can significantly reduce the number of packets required for path reconstruction.5,Research on the security authentication in hybid P2P network enviroment. Because of a variety of security issues caused by the lack of authentication for peer nodes, we consider the 3 GPP authentication and key agreement(AKA) to be used in authentication in hybid P2P network. However, the 3GPP AKA protocol has some security risks, we investigate the security of the 3 GPP AKA protocol, and analyze four types of attacks to which it is vulnerable. To solve the security problems mentioned above, we present an efficient authentication and key agreement protocol, which is based on public key cryptography, under the circumstances of location updating and location immovability, adopt formal analysis to prove the security of two protocols proposed by this paper, and compare it with other protocols from the aspect of security. The result shows that our protocol proposed can significantly enhance the security of 3GPP AKA protocol. Finally, we apply our proposed AKA protocol to security authentication in hybid P2P network, and enhance the security of hybid P2P network system.