The Howdy Glossary

XACML (eXtensible Access Control Markup Language) is an XML-based standard developed by the Organization for the Advancement of Structured Information Standards (OASIS), designed to manage and articulate access control policies. It provides a comprehensive policy language for defining access control needs and a request/response language for communication between enforcement components. As a result, it eliminates the need for custom programming by allowing authorization logic to be encoded in freeform policies applicable across various application domains.

XACML stands out due to its use of XML syntax, enabling detailed representation of users, resources, actions, conditions, obligations, and advice. This structured approach allows simple rules to be combined into complex authorization scenarios, offering fine-grained control over resource access. The reference architecture provided by XACML guides implementers on integrating it into their security models consistently and effectively. While not as widely used as methods like role-based or attribute-based access control (RBAC or ABAC), XACML's advanced capabilities ensure authorized entities are granted specific operation permissions through tailored policies.

Competing with RBAC and ABAC in the broader landscape of access control solutions, XACML offers unique advantages such as fine-grained access capabilities and flexibility in defining intricate authorization scenarios without custom programming requirements. Unlike RBAC's predefined role assignments or ABAC's attribute-oriented decisions requiring extensive data management, XACML uses a rule-based approach with structured XML syntax for precise policy definitions that can be enforced across diverse application domains. Its interoperability makes it an adaptable solution for organizations seeking standardized methods to manage complex access controls within their information systems or application platforms.