本项目针对云环境可信性现有研究的不足，研究在云操作系统中设立复合信任链支撑机制的问题。研究内容有三个方面，1、云端环境对象可信性评判模型研究，2、云端环境复合信任链构建方法研究，3、支撑复合信任链的云操作系统机制研究。研究目标是为云操作系统提出一套支撑复合信任链的有效机制，它们支撑复合信任链的构建，能为用户探知目标对象在动态复杂云端环境中的信任状态，从而为用户了解云端环境的可信性提供有效途径。拟解决两个关键科学问题，1、动态复杂云端环境的信任传递问题，2、云端环境中非透明方式的信任状态测定问题。将取得三个创新点，1、提出一种对云端环境中的对象可信性进行评判的方法，2、提出一种为云端环境中的对象构建复合信任链的方法，3、提出一种由云操作系统支撑复合信任链构建的方法。

Aiming at the shortage of existing research on trust in clouds, This proposal is to research issues of creating supporting mechanisms for compositional chains of trust(CCoT) in a cloud operating system(COS). The work consists of three parts. 1.On trust evaluation models for objects in a cloud. 2.On approach to establishing CCoTs in a cloud. 3.On COS mechanisms that support CCoTs. The research goal is to put forward a set of effective mechanisms that support CCoTs, which support the establishing of CCoTs, and are capable of capturing trust status of a target object in a dynamic and complex cloud, and hence can provide an effective way for users to understand trust in a cloud. Two key scientific issues are to be resolved. 1.The issue of transitive trust in a dynamic and complex cloud. 2.The issue of measuring trust status in a cloud in an opaque style. Three innovative contributions will be made. 1.To propose an approach to evaluating trust in an object in a cloud. 2.To propose an approach to establishing CCoTs for an object in a cloud. 3.To propose an approach to establishing CCoTs under the support of the COS.