The Research On Trust-aware P2P Topologies And Constructing Technologies

Peer-to-Peer computing is a novel Internet-based computing paradigm which is being studied widely in recent years. The final goal of p2p systems is to pool end-systems in Internet-scale as more as possible to construct large-scale cooperating and resource-sharing environments. In an ideal p2p network model, the significance of all peers is equal, and the network topology is symmetrical.Different with ideal case, the actual p2p systems are usually ad-hoc, and the heterogeneous nature of Internet make peers in large-scale p2p enviroments being quite different in characteristics such as computation power, storage capablity and network bandwith etc., it is hard to get a stable, efficent and fairness p2p network if we neglect the dynamicity and the heterogeneity of p2p system in its construction.Some practices and researches have proved that, the dynamicity and the heterogeneity of p2p system are heavily subjected to the participant strategies of peers in p2p environment. At this point, the p2p system designer must take the autonomy of peers into his(her) account in the p2p system design.Peer trustworthiness in p2p system is essential a synthesis of peer's subjective and objective characteristics, and is a reasonable metric which could be used to evaluate the peer's participant strategy. In this paper, the situation in which peers have different degree in trustworthiness is called trustworthiness heterogeneity, and the p2p topologies which consider the trustworthiness heterogeneity phenomenon in its construction is called trust-aware p2p topologies.Trust-aware p2p construction makes p2p system more fairness, efficient, optimized, stable and usable.Focusing on trust-aware p2p construction, the destination of this paper is restricted in followed sub domains and related techonologies:(1) The construction of unsymmetrical structured p2p topologies.The symmetrical construction approach in traditional p2p systems makes it difficult to utilize the capablity of trusted peers adequately, on the contrary, the unsymmetrical construction lends a space to leverage the trusted peers to get a more robust and efficient p2p network.(2) The selective searching mechanism in structured p2p topologies. An obstacle which affect the use of trust in structured p2p network is the lack of selectivity for its original DHT accurate object locating mechanism, importing selective searching mechanism on one hand makes peer have selective choices on its searching results according to their trustworthiness, on the other hand, selective searching mechanism also enlarges the applicable domains of structured p2ptopologies.(3) Distributed trust model for p2p environments. The quantity of peer trustworthiness rely on a efficient trust model and trust management mechanism, current trust model and trust management mechanism of p2p systems have some limitations in the model integrality and security, which make it necessary to build a new trust model and related management mechanism for our work in this paper.(4) A dynamical topology construction based on peer trustworthiness. There are no efficient incentive mechanisms in current unstructured p2p(such as file-sharing)applications,and the architecture of known incentive mechanisms are usually centralized, and is limited in sharing incenting, without consideration on the network fairness and topology optimization. Actually, leveraging distributed trust mechanism and topologies evolution could not only elegantly avoid the centralized architecture which existed in current p2p incentive systems, but also could come to the incentive effect of file sharing and network fairness.The (3) is the fundmental of other work of this paper, but its trust management mechanism is also built on the work of (1) and (2). The (4) is essentially an application which leverages the work of (1) and (3).This thesis aims at making four major contributions: Prompted a d-tree based trust-aware and unsymmetrical p2p topology, Terrace. Same as the traditional structured DHT network, the locating cost in Terrace is O(logN) and the maintaining co...