【作者】 朱一群；

【导师】 李建华；

【作者基本信息】 上海交通大学 ， 通信与信息系统， 2008， 博士

【摘要】 Web services(Web服务)作为一种新兴的Web应用模式,是一种崭新的用于分布式环境中的计算模型。Web服务是在Internet网络上基于一系列开放的标准协议技术(如SOAP、UDDI和WSDL等)进行信息交互的,具有松散耦合、平台无关性、可复用性好、开放性等特点,这些使得Web服务在体系结构、设计、实现与部署等方面更加合理。面向Web服务体系的应用和发展,使得Internet上信息资源共享更为有效、广泛、便利。然而,随着网络发展和网络信息越来越丰富,资源共享越来越频繁,带来的网络信息安全问题也随之日益突出,其中,资源受到非法用户的访问和获取,成为Web服务安全的重要弱点之一。访问控制、授权管理是保护面向Web服务资源安全的重要技术和内容,也是当前面向服务的信息安全领域中的研究热点。本文围绕着面向Web服务通信应用系统中的安全问题,对访问控制和授权管理进行了比较深入的研究。本文的研究内容主要围绕以下三个方面:首先,研究了Web服务的主体和客体的动态特性,分析了Web服务的应用特点,提出了面向Web服务的动态分级访问控制模型。在面向服务的应用系统中,提出请求的主体和提供服务资源信息的客体都具有较高的动态特性,要求访问控制策略能满足适应主客体的动态变化,同时,Web服务应用系统具有服务和服务属性两种需要保护的信息。在提出的模型中,角色扮演者可以满足主客体动态变化特性的安全需求,分级访问控制策略思想可以同时保护服务和服务属性的信息。本文给出了模型的详细定义和描述,并给出了模型的授权机制和实现机制。其次,针对大量用户增长的安全需求和资源信息细粒度化的应用特点,提出了面向Web服务的通用基于属性的访问控制模型。随着提供服务的企业发展,资源信息更为丰富。为了保护更细粒度的资源信息安全,系统基于资源的多种不同属性制定大量丰富的访问策略。同时,在许多服务应用环境里用户数目正在不断增长。这些使得用户——角色分配和角色权限管理的工作变得复杂、繁重,需要一个比较灵活的授权模型,能适应这些新的安全需求。本文提出的模型分析了访问策略中资源属性和用户属性的关系,提出了单一属性表达式和复合属性表达式、复合权限的概念,通过定义多组用户角色,灵活分配用户角色,降低了系统角色管理和权限管理复杂度,能适用于广泛普遍的服务应用环境。最后,针对转授权委托中的时间限制,提出了基于周期时间限制的基于权限的转授权模型。本文描述了转授权模型的形式化定义,定义了模型的转授权判定条件,给出了转授权用户和被授权用户的资格判定条件,分析了模型的授权,给出了模型的授权树分析,最后给出了转授权撤销的几种方式。更多还原

【Abstract】 Web services are well known of a new distributed computing mode, and are widely accepted because of its characters of reusing and interoperability. Web services are loosely coupled applications using well-known XML protocols (such as SOAP, UDDI, WSDL) for representation and communication across the Internet. With the application and development of Web services, resources are shared more widely and efficiently. However, the open nature of the Internet and its loop-coupling construction make Web services vulnerable to various types of security attacks. The Web services security becomes the important factor that restricts Web services further to develop. One aspect of security vulnerabilities in Web services is whether or not services are accessed by authorized users. It is valuable to study how to efficiently prevent unauthorized user from accessing Web services.This dissertation focuses on the security issue of Web services security. The research is concerning the access control, and it can be divided into three parts:Firstly, we study the dynamic characteristic of subject and object and application nature for Web services, and present a dynamic hierarchical RBAC model for Web services. In the environment of web service application, both the subject of invoking request and object of providing service resources have dynamic nature, so, this needs access policies be adapt to dynamic changement of subject and object. Also, both resource and resource attributes for Web services must be protected. In our presented model, actor can satisfy the needs of dynamic changement of subject and object, and hierarchical access policies can protect both information of resource and resource attributes. We define the model and give its detailed description, and give the authorization framework.Secondly, we present a general attribute based access control model for Web services in order to satisfy security requirements of growing numbers of users and rich policies that involve many resource attributes. With the development of enterprises that providing services, system makes many access policies based on many resource attributes in order to protect resource information, and the numbers of users are increasing, which induce user-role assignment and permissions management to be formidable tasks. So, we present a new access control model to meet the security needs. The proposed model introduces notions of single attribute expression, composite attribute expression, and composition permission, and defines a set of elements and relations among its elements, and makes a set of rules that assign roles to user by inputing user’s attributes values. The model can support more granularity resource information and rich access control policies, and is a general access control model that can be used to wider applications for services.Finally, we present periodicity constraints-based permission-based delegation model.The presented model combines periodicity constraints into PBDM model. We present delegation judgement condition, and also present qualification judgement conditions of delegator and delegatee, and give a delegation tree in analyzing delegation, and give several modes of revoking delegation.更多还原