Abstract: In the cloud, trust issue is particularly important due to the high concentration and sharing of resources.Meanwhile trusted computing as a new type of security mechanism, can protect the user's data security, and provide users with a trusted computing environment. Therefore, the combination of the trusted computing and cloud computing technology is the novel idea for the study of cloud security. The traditional trusted computing needs to proceed from the physical trusted root and construct a complete trusted chain in the system, however the user application is running in a virtual computing environment for cloud computing, so the construction of trusted roots and the transmission of trusted chains are the challenges of trusted computing in cloud environments. In view of the above challenges, firstly, by analyzing existing mechanisms of cloud virtualization security, this paper point out the data security risks from untrusted cloud services and corresponding countermeasures. Then propose cloud security framework based on trusted computing from the research of construction of virtual trusted roots ,the trust chain transmission, active monitoring, reliable isolation, and secure access for trusted cloud mechanism. At last, it is pointed out that it is necessary to start from the top to design a trusted cloud architecture that must possess the characteristics of cooperative engagement, active immunity and autonomy control for future research.

Key words: trusted computing, cloud computing, security framework, virtualization technology, trusted root

摘要： 云环境中，由于资源的高度集中、共享，信任问题显得尤为重要，与此同时可信计算作为一种新兴的安全机制，可以保障用户的数据安全，为用户提供可信任的计算环境，因此将可信计算与云计算技术相结合是云安全研究的一种新思路.传统可信计算需要从物理的可信根出发，并且在系统中构造完整的可信链，而在云计算中，用户应用是在虚拟的计算环境中运行，因此虚拟可信根的构造以及可信链的传递等都是云环境中可信计算面临的新挑战.针对以上问题，首先从分析现有云虚拟化安全机制出发，指出了云服务不可信带来的数据安全风险及其相应的对策；然后，从虚拟可信根建立、信任链传递、主动监控、可信隔离与安全接入等技术对可信云核心机理进行研究，提出了基于可信计算的云安全框架；最后，总结指出必须从顶层设计出发，提供具备能协同作战、主动免疫、自主可控的可信云架构是未来研究的趋势.

关键词: 可信计算, 云计算, 安全框架, 虚拟化技术, 可信根