A Study of Attribute-Based Access Control (ABAC) Languages: A Real-World Perspective

Open computing environments need a flexible mechanism to support fine-grained access control for the dynamic nature of the requests to allow or deny while accessing the resources. Access control as a tool involves regulating requests for data and services within a system to determine whether they should be granted or denied. The Attribute-Based Access Control (ABAC) model, along with its policies and languages, is constantly evolving to create frameworks that are flexible and expressive enough to meet the security needs of new applications and real-world scenarios. Access control policy languages differ in how they specify and manage policies and attributes, as well as in how they compute and enforce decisions. To the best of the authors' knowledge, no research papers are considered to provide a real-world perspective in terms of policy definition and highlight their features for widely adopted ABAC policy languages. This paper explores widely adopted ABAC policy languages such as Extensible Access Control Markup Language (XACML), Next-Generation Access Control (NGAC), Polar, and Streaming Attribute Policy Language (SAPL), offering a comprehensive implementation perspective of how policies are written in these languages.