TWC: Medium: Collaborative: Foundations of Application-Sensitive Access Control Evaluation

传统上，访问控制方案是根据原始表达能力进行比较的（即，它们可以编码的策略以及如何更改这些策略）；然而，这种比较忽略了将在其中部署方案的应用程序的需求。对于某些应用程序，最具表现力的方案可能过于复杂，不一定是最合适的。为此，本项目研究了适用性分析问题：给定系统的访问控制工作负载、一组候选访问控制方案和一组特定于应用程序的成本指标，哪个方案最能满足系统的需求？目标是创建一个适当性分析框架，该框架足够严格，对研究人员和理论家有用，同时对安全实践者仍然可用。这样的框架将有助于形式化访问控制方案的特定应用的优势和局限性，使研究人员能够精确地描述方案最适合的场景，允许评估所提议方案的新颖性和实用性，并帮助分析人员诊断现有系统的缺点。特别是，该项目将开发(1)一个特定于应用程序的、基于工作负载的框架，用于分析访问控制方案的适用性，该框架足够丰富，可以比较顺序和并发系统中的逻辑、扩展和混合方案；(2)使用自定义指标量化方案适用性的成本分析组件；(3)自动化一系列适用性分析任务的工具。一个真实世界的安全工作负载，基于pki的网络认证和授权，将被用来评估结果。

Access control schemes are traditionally compared in terms of raw expressive power (i.e., the policies they can encode and how those policies can be changed); however, such comparisons ignore the needs of the application within which a scheme will be deployed. For some applications, the most expressive scheme may be overly complex and not necessarily the best fit. To this end, this project investigates the suitability analysis problem: Given a system's access control workload, a set of candidate access control schemes, and a set of application-specific cost metrics, which scheme best meets the needs of the system?The goal is to create a suitability-analysis framework that is sufficiently rigorous to be useful to researchers and theoreticians, while remaining accessible to security practitioners. Such a framework will help formalize an access control scheme's application-specific strengths and limitations, enable researchers to precisely describe the scenarios for which a scheme is best suited, allow assessment of the novelty and utility of proposed schemes, and help analysts diagnose shortcomings in existing systems. In particular, the project will develop (1) an application-specific, workload-based framework for analyzing the suitability of access control schemes that is sufficiently rich to compare logical, extensional, and hybrid schemes in both sequential and concurrent systems; (2) a cost analysis component that quantifies a scheme's suitability using custom metrics; and (3) tools that automate a range of suitability analysis tasks. A real-world security workload, PKI-based authentication and authorization on the web, will be used to evaluate the results.