A Study On Cloud Computing Environment For Multi-user Hierarchical Trust Management System

With the development of high-speed Internet and mobile Internet, The network access capability of PC and the mobile terminal has been greatly improved, so that they do not have to rigidly adhere to the limits of their computing resources. Also with mature technologies such as virtualization, cloud computing framework technology and the rapid development of IT enterprises, the demands of storage and distributed computing in the cloud is also increasing. Under this requirement the cloud computing technology was born. Cloud computing is a combination of utility computing, grid computing concept, it is a new computing paradigm. Through the Internet it provide dynamic, scalable to users, virtualized computing resources, according to the user needs to use to pay. Cloud itself is platforms or facilities by the virtual server, virtual data centers through the Internet to provide users with a powerful applications.However, cloud computing is quite different with other computing environments. In cloud computing environment, the type of an entity involved in cloud computing, there are significant differences. Cloud computing environment is often non-existent centralized management mechanism. Diversity of cloud computing environment with the service entity makes it different from other dynamic distributed environment, and the interaction between cloud computing environments entities often cooperation. Because of the above reasons, the traditional trust management technology can not apply in the cloud computing environment. And new application computing environment appeared to bring some new problems, such as:the existing models mostly define the entity in cloud computing into consumers, service providers, ignoring the identity of cloud components, so cannot correspond exactly to the cloud diversity of expression computing environment entity. Research focused on the trust relationship between service providers and consumers, ignoring the relationship between consumer and consumer and between cloud service providers and cloud service providers. Certain circumstances will conduct collaborative interaction between entities in a cloud computing environment, collaborative trust between entities of the same type has not been adequately studied. And the dynamic of cloud computing environment mainly refers to the definition of the identity of the entity, type of service as well as the expected trust'measurement. All the problems lead to different dynamics defined other distributed computing environment trust model cannot be applied to cloud computing environments.Therefore, this paper mainly do three tasks:First, this paper present a Layer Based Cloud Trust Model (LBCTM) for the cloud environment. LBCTM. added the concept of "cloud components", define the type of entity in cloud computing environments into cloud, cloud components and renters. LBCTM is divided into three layers:the cloud layer, cloud component layer, renter layer. The trust relationship is divided into two kinds, trust between layers and inner layers. For the relationship of trust between layers, component layer and renter layer conducts trust relationships through interaction. Component is a part of the clouds, so the credibility of component can directly affect the credibility of the cloud. Similarly, when renter interact with component, the credibility of cloud which component belongs has a direct impact on the credibility For trust in the inner relationship, the different components during the collaboration as well as different renter will assess trust within the layer occurs during information-sharing, trust assessment through the inner layer of a credible assessment of cooperative entities supervised manner. Between different layers of the hierarchy there exists the transitive trust flows respectively, the trust relationship between entities more three-dimensional. LBCTM simplified the trust relationship measurement of cloud entities and the complexity of the trust, it meet the needs of different entities.Second, on the basis of LBCMT, this paper presents a Trust Level Agreement Based Cloud Trust Model (TLABCTM). TLABCTM restrain the interaction between the entities. Trust Level Agreement is the guiding rule of cloud entities interacting. Agreement makes some abstracts of interactions in cloud computing environment, only the specific types of interactions are allowed to occur. Meanwhile, the agreement optimize the entity set of recommend entity, reduce the computational complexity without too much influences of the accuracy of trust assessment. From the user's point of view, TLABCTM classify the identity of the entity, type of service, renter access to the cloud service and the service request to adapt according to different service requests to meet the dynamic cloud environments.Third, this paper build a software system to achieve the above-mentioned trust model for cloud computing. The development of system comply with J2EE standards, has good compatibility and scalability, which makes it easy to cooperate with the existing cloud management system. Trust management system provides the recorded of interaction, the inquiry of interaction detail, trust assessment between entities, credible decision-making, which contribute to the improvement of application in cloud computing.