RBAC与MAC在多级关系数据库中的综合模型

多级安全数据库的安全策略需要各种模型来表达,访问控制模型是其中之一.强制访问控制(MAC)模型保证多级数据库中的信息流动符合系统的安全策略.利用基于角色的访问控制(RBAC)来实现MAC能方便多级安全数据库的权限管理.提出了一种MAC与RBAC的综合模型,定义了多级角色与内部角色的概念,并给出了综合模型中经过修改后的操作,使得系统能自动地完成符合强制访问控制策略的用户权限的管理.该模型方便了管理员的权限管理,适合用户较多,安全层次比较复杂的多级关系数据库系统.最后给出了模型的部分实现机制.

RBAC实施中国墙策略及其变种的研究

中国墙策略的目的是防止在有竞争关系的企业间访问信息导致的利益冲突.著名的中国策略模型包括Brewer等人提出的BN模型和Sandhu提出的基于格访问控制模型实施的中国墙模型.然而这些模型都存在严重的缺陷:灵活性不够或者实施不方便.RBAC是目前主流的访问控制模型,该模型的特点是策略中立.基于RBAC模型全面研究了实施中国墙策略及其各种变种策略的方法,利用角色体系和RBAC的约束机制,给出了具体的构造方法,讨论了这些构造中约束的形式化描述方法.与传统的中国墙模型相比,更加灵活,并可在支持RBAC的系统中直接实施.

基于授权策略的RBAC信息流控制

RBAC没有明确定义非法信息流，也没有提供信息流控制机制．RBAC系统中主体的访问操作 可以引起客体之间的信息流，使用户访问到未授权的信息．首次从授权策略的角度形式化地定义了 RBAC非法信息流，提出了一个检测RBAC配置中用户可以引起的非法信息流的算法，给出了一个动态 信息流控制算法．确保了RBAC访问控制目标的实现，增强了RBAC系统的安全性．

一种基于RBAC的电子商务匿名性与可追究性实现方案

提出了一种基于RBAC思想对可信第三方功能进行分类并结合其他一些技术实现电子商务中匿名性与可追究性的解决方案，主要涉及三个主要过程：用户的注册控制、交易过程的控制及投诉处理过程。通过对注册用户的信息进行加密并对加密密钥进行分割保存来实现匿名性，通过对交易过程安全协议的设计及TTP功能的划分达到可追究性要求，并对可追究性的实现给予证明。

P-RBAC:一种门户环境下的访问控制模型

门户能够有效地实现异构信息之间的集成与协作,并为用户提供可定制、统一且遵循规范的访问服务.然而,由于门户所具有的这些不同于普通Web应用的特性,也使得传统访问控制模型无法在门户中直接使用.提出了一种面向门户系统的访问控制模型p-RBAC.P-RBAC扩展了传统的基于角色访问控制模型,并根据行为状态进一步分为静态模型和动态模型.P-RBAC给出了静态模型和动态模型上的行为规则,提出了具体的动态权限指派和角色组织策略,从而有效地解决了门户的访问控制问题.实际的应用案例证明,P-RBAC模型能够适用于门户的访问控制,并较之传统访问控制模型更高效可行.

具有冲突约束的RBAC模型的形式化规范与证明

中国计算机学会

一种基于角色访问控制(RBAC)的新模型及其实现机制

文中对基于角色访问控制（ｒｏｌｅ－ｂａｓｅｄ ａｃｃｅｓｓ ｃｏｎｔｒｏｌ， ＲＢＡＣ）研究中的两大热点——模型的建立和实现进行了较深入的研究，提出了一种新的ＲＢＡＣ模型——ＮＲＢＡＣ模型．这一模型除具有全面性外，比之已有的ＲＢＡＣ９６ 模型还具有接近现实世界和形式统一的优点．针对ＮＲＢＡＣ模型的实现，文中又提出了一种新的ＲＢＡＣ实现机制——基于时间戳和素数因子分解的二进制双钥－锁对（ ＴＰＢ－２－ＫＬＰ）访问控制方案．它不仅能很好地克服已有ＲＢＡＣ实现机制存在的缺点，还兼备了对锁向量修改次数少和发生溢出可能性小的优点．

Smart-RBAC

Generally, smart campus applications do not consider the role of the user with his/her position in a university environment, consequently irrelevant information is delivered to the users. This dissertation proposes a location-based access control model, named Smart-RBAC, extending the functionality of Role-based Access Control Model (RBAC) by including user’s location as the contextual attribute, to solve the aforementioned problem. Smart-RBAC model is designed with a focus on content delivery to the user in order to offer a feasible level of flexibility, which was missing in the existing location-based access control models. An instance of the model, derived from Liferay’s RBAC, is implemented by creating a portal application to test and validate the Smart-RBAC model. Additionally, portlet-based applications are developed to assess the suitability of the model in a smart campus environment. The evaluation of the model, based on a popular theoretical framework, demonstrates the model’s capability to achieve some security goals like “Dynamic Separation of Duty” and “Accountability”. We believe that the Smart-RBAC model will improve the existing smart campus applications since it utilizes both, role and location of the user, to deliver content.

Ingegnerizzazione di RBAC-MAS in TuCSoN

L'obiettivo della tesi è la creazione di un'infrastruttura di tipo RBAC (Role Based Access Control), adibita al controllo degli accessi all'interno del linguaggio di coordinazione TuCSoN. Il punto di partenza si basa sull'analisi del lavoro sviluppato dall'Ing. Galassi: "Modello di sicurezza e controllo di accesso in una infrastruttura di coordinazione: architettura e implementazione". Usando questa come base teorica di partenza, si sono estrapolati i concetti chiave e si è data vita ad un'implementazione funzionante e di semplice utilizzo di RBAC in TuCSoN.

SELinux policy management framework for HIS

Health Information Systems (HIS) make extensive use of Information and Communication Technologies (ICT). The use of ICT aids in improving the quality and efficiency of healthcare services by making healthcare information available at the point of care (Goldstein, Groen, Ponkshe, and Wine, 2007). The increasing availability of healthcare data presents security and privacy issues which have not yet been fully addressed (Liu, Caelli, May, and Croll, 2008a). Healthcare organisations have to comply with the security and privacy requirements stated in laws, regulations and ethical standards, while managing healthcare information. Protecting the security and privacy of healthcare information is a very complex task (Liu, May, Caelli and Croll, 2008b). In order to simplify the complexity of providing security and privacy in HIS, appropriate information security services and mechanisms have to be implemented. Solutions at the application layer have already been implemented in HIS such as those existing in healthcare web services (Weaver et al., 2003). In addition, Discretionary Access Control (DAC) is the most commonly implemented access control model to restrict access to resources at the OS layer (Liu, Caelli, May, Croll and Henricksen, 2007a). Nevertheless, the combination of application security mechanisms and DAC at the OS layer has been stated to be insufficient in satisfying security requirements in computer systems (Loscocco et al., 1998). This thesis investigates the feasibility of implementing Security Enhanced Linux (SELinux) to enforce a Role-Based Access Control (RBAC) policy to help protect resources at the Operating System (OS) layer. SELinux provides Mandatory Access Control (MAC) mechanisms at the OS layer. These mechanisms can contain the damage from compromised applications and restrict access to resources according to the security policy implemented. The main contribution of this research is to provide a modern framework to implement and manage SELinux in HIS. The proposed framework introduces SELinux Profiles to restrict access permissions over the system resources to authorised users. The feasibility of using SELinux profiles in HIS was demonstrated through the creation of a prototype, which was submitted to various attack scenarios. The prototype was also subjected to testing during emergency scenarios, where changes to the security policies had to be made on the spot. Attack scenarios were based on vulnerabilities common at the application layer. SELinux demonstrated that it could effectively contain attacks at the application layer and provide adequate flexibility during emergency situations. However, even with the use of current tools, the development of SELinux policies can be very complex. Further research has to be made in order to simplify the management of SELinux policies and access permissions. In addition, SELinux related technologies, such as the Policy Management Server by Tresys Technologies, need to be researched in order to provide solutions at different layers of protection.

An approach to access control under uncertainty

In dynamic and uncertain environments such as healthcare, where the needs of security and information availability are difficult to balance, an access control approach based on a static policy will be suboptimal regardless of how comprehensive it is. The uncertainty stems from the unpredictability of users’ operational needs as well as their private incentives to misuse permissions. In Role Based Access Control (RBAC), a user’s legitimate access request may be denied because its need has not been anticipated by the security administrator. Alternatively, even when the policy is correctly specified an authorised user may accidentally or intentionally misuse the granted permission. This paper introduces a novel approach to access control under uncertainty and presents it in the context of RBAC. By taking insights from the field of economics, in particular the insurance literature, we propose a formal model where the value of resources are explicitly defined and an RBAC policy (entailing those predictable access needs) is only used as a reference point to determine the price each user has to pay for access, as opposed to representing hard and fast rules that are always rigidly applied.