Abstract:

The service consumers lack trust in cloud service providers in the interactive process. Aiming at the problem, a trust model of cloud computing based on Service Level Agreement (SLA) was proposed. In the model, when registering to a third-party trust platform which called service center, a cloud service provider must submit its strength evaluation report on its strength, operations, technologies and service attributes, etc. According to the relevant criteria, service center made an evaluation of the cloud service provider and got the system trust. Then, the system trust was combined to traditional reputation. Thus, direct trust, indirect trust and system trust were made as three important factors for evaluating a cloud service provider, and the last trust value was calculated. Finally, the service consumer could make the SLA negotiation with the service provider according to the service and the last trust value, was used to determine the selection from multi-service providers. Thus, the dishonest or less reputable cloud service providers were excluded. The experimental results show that the last trust value is obtained more comprehensively and accurately due to the introduction of system trust and service consumer can select the cloud service provider with high credibility, which can effectively prevent the dishonest behaviors of cloud service providers and improve the success rate of interaction in the proposed trust model.

Key words: cloud computing, trust, reputation, Service Level Agreement (SLA), service property

摘要：

针对用户在交互过程中对云服务商缺乏信任的问题,提出了一个基于服务等级协议(SLA)的云计算信任模型。在该模型中,云服务商在向服务中心——可信的第三方平台注册时,首先提交自身的实力评估报告,说明其实力、运营、技术及提供的服务属性等,服务中心根据相关的评价标准对该云服务商进行评估,得到系统信任;其次把系统信任引入到传统的声誉机制中,把系统信任、直接信任和间接信任作为评估一个云服务提供商的三个重要因素,并计算出云服务商的综合信任度;最后用户根据云服务商提供的服务和综合信任度与其进行SLA协商,确定最终交互对象,屏蔽掉不诚实或信誉较低的云服务商。实验结果表明,在基于服务等级协议的信任模型中,由于引入了系统信任,云服务商综合信誉的获得更全面准确、有效地防止了云服务商的不诚信行为,提高了交互的成功率。

关键词: 云计算, 信任, 声誉, 服务等级协议, 服务属性