【作者】 陈萌；

【导师】 陈海；

【作者基本信息】 南昌大学 ， 计算机应用技术， 2008， 硕士

【摘要】 网格安全是网格计算系统中必不可缺少的机制。由于网格系统的异构、动态、多域等特点,网格安全问题比网络的安全问题更加复杂。为了解决网格环境的动态性和不确定性带来的安全问题,将信任机制引入到网格环境中,对实体的行为进行评价,反映出实体网络行为的可信程度。本文通过研究和总结现有的信任模型,从信任的定义、信任的表达、信任的存储和信任关系的变化等方面出发给出了一个较完整的网格信任模型:基于D-S理论与信任路由的网格信任模型。主要有以下几方面的工作:1.结合本模型的特点对信任做出新的定义,并用综合信任来代替推荐信任,使信任的表达更为合理,对信任度的计算更为简单。2.采用多方面的信任表达方式:结点的直接信任度、结点的综合信任度、结点的历史信任度、自治域的综合信任度和自治域的历史信任度。使得网格中一个结点对另一个结点的信任度的评价的信息更全面、评价方式更灵活和自由。3.提出一种基于信任路由的信任存储管理模型,该模型结合了集中式存储和分布式存储的优点。把网格中的所有信息存储在信任路由中,这样的信任路由分布在网格中的各个自治域,查询时只需按集中式查询的方法查询最近信任路由。当某个信任路由有信息更新时,用类似于因特网的路由器的更新方法来保持各信任路由信息的一致性。4.给出结点的直接信任度、结点的综合信任度、结点的历史信任度、自治域的综合信任度和自治域的历史信任度的计算和更新推导公式。5.提出一种改进的D-S证据融合规则:基于冲突比例的冲突证据融合规则,用新的规则对信任度进行融合。使得在对信任度进行融合可以很好的消除恶意结点的影响,又有很快的证据集中速度。6.在对信任度时衰性的处理上,采用最近一段时间结点交易记录来更新结点和自治域信任度。避免了时间因子选择和计算复杂的困难,并且可以解决交易记录表无限增大的问题。更多还原

【Abstract】 Grid security is the essential mechanism in grid computing systems. Grid system consists of various resources, and the resources have more features of change, geographical dispersion and heterogeneous systems, which make security issues of the grid system much more complex than the network. In order to solve the security issues incurred by the dynamic and uncertainty of grid environment, we introduce the trust mechanism into the access control, it is necessary to evaluate the network behavior of entities in grid computing. Thus, the evaluation of the entities’ behavior can reflect his reliability.A new grid trust model, based on D-S theory and trust route, was proposed in this paper through to the exiting models research on trust definition, trust expression, trust memory and trust relations aspects and so on.The contributions of this dissertation are as follows:1. A new trust definition was made according to the characters of this model. Replaces the recommendation trust with the synthesis trust, trust expression more reasonable and computation simpler.2. Uses many kinds of trust expression: node direct trust, node synthesis trust, node historic trust, domain synthesis trust, domain historic trust. it causes a node in the grid to evaluate another more comprehensively and more freely.3. Proposed a trust memory management model based on trusts route with the merits of central and distributional. All trust information are saved in every trust route which distributes in each autonomous domain, using central method to inquiry trust information in the trust route, using similar method as internet router to update information for trust uniformity.4. Makes the computational formulas of node direct trust, node synthesis trust, node historic trust, domain synthesis trust and domain historic trust.5. Proposed an improved combination rule of D-S theory based on conflict ratio. by which can remove the influence of bad nodes very well, with faster centralism speed. 6. Using recently records to update node and domain trust values, to resolve the problem of trust weaken by time, it can not only avoid the difficulties of time factor choice and computation complex, but also prevent the infinite increase of transaction record sheet.更多还原