Research & Application On Trust In Grid Environment

Grid technology is another great technological progress after the emergence of Internet. The goal of Grid is to provide large-scale collaborated computations and storage of huge data through completely resource sharing among the resource of computing, storage, communication, software, and knowledge and so on in Internet. Grid Security guarantees the normal running of Grid system, and trust mechanism is the basic sustentation of every security system. Grid has its own security and trust requirements, which differ from traditional network. There is still lack of integrated trust mechanism solution to satisfy those security and trust requirements so far.The thesis starts from the basic background knowledge and analyses the characteristics and structures of Grid environment, which bring challenges to security and trust mechanism of the Grid. So it is pointed that the trust mechanism in the security of Grid environment is very important. Due to Grid systems, which face to different applications, take different attention to trust mechanisms, the thesis proposes a comprehensive solution for solving trust problems in Grid. On the whole, the solution consists of two parts as static trust and dynamic trust.Firstly, the static trust is mostly identity trust. The thesis proposes a new structure of proxy certificate chain, which can change its own trust depth, by analyzing the mechanism of long proxy certificate chain in GSI (Grid Security Infrastructure). GSI is the grid security architecture of the Globus project, which is the most famous project in Grid area. The new solution solves several problems of the long proxy certificate chain such as its high maintenance but low efficiency of authentication, and improves reliability of certificate chain.Secondly, the dynamic trust is mostly behavior trust, which is based on identity trust and takes more attention to behavior control of entities passed by identity authentication. Trust value is the most important reference between entities in Grid when they trade each other. So it is also very important how to get their trust value. The thesis expounds the application of tow algorithms of dynamic trust value in Grid environment.The first one is the algorithm of recommendation based dynamic trust value, referring to social people trust relationship model. This kind of algorithm that is researched mostly so far can accept that grid nose have break faith behavior once a while. The thesis expounds the application of an algorithm in Grid environment.The second one is the algorithm of time-frame based dynamic trust value, referring to a kind of trust value algorithm in P2P network. It is improved to fit the application in Grid environment. Due to the defects in the first algorithm above, this algorithm enhances effectivity in countering malicious entities regarding strategic altering behavior and cooperate-deceiving. So it improves stability and dependability of entities in Grid.And then, the thesis proposes a comprehensive solution for solving trust problems in Grid environment. Grid systems that face to different applications and take different attention to trust mechanisms, considering static trust and different algorithms of trust value, choose right trust mechanism as trust base of cooperation between entities.At last, it points out future research topics of this idea.