关键词: 公有云, 云计算, 云安全, 软件即服务（SaaS）, 隐私保护

Abstract: Protection of user privacy has always been important issues affecting cloud computing promotion. Currently, researches on user privacy protection for cloud service providers are rare and designed for specific areas and there is not a more common scenario. This seriously hampers the users’ trust in the cloud service provider and cloud computing services. To resolve this problem, this paper begins with an analysis of the characteristics of information disclosure in a cloud environment, and puts forward an idea of making a cloud layer or module mutual isolated and restricted about user privacy protection, based on the features of cloud computing services and module. Based on this, it concludes with a set of full privacy protection for PaaS and SaaS-based layer separation. Let different cloud service providers provide PaaS layer and SaaS layer services separately, and let cloud service providers limit the other disclosure of user privacy according to the corresponding specification when they provide service. Then it makes a detailed security analysis of the programme and utilizes an example to explain the role in user privacy protection. The cloud computing is implemented in the framework of the program in general and can pass for all kinds of SaaS services, with strong theoretical and applied value.

Key words: public clouds, cloud computing, cloud security, Software as a Service（SaaS）, privacy protection