Read the original article: A Basic Introduction to XACML
What Is XACML?
XACML (eXtensible Access Control Markup Language) is an XML-based language for access control that has been standardized by the Technical Committee of the OASIS consortium. XACML is popular as a fine grain authorization method among the community. XACML describes both an access control policy language, request/response language and reference architecture. The policy language is used to express access control policies (who can do what when). The request/response language expresses queries about whether a particular access should be allowed (requests) and describes answers to those queries(responses). The reference architecture proposes a standard for deployment of necessary software modules within an infrastructure to allow efficient enforcement of policies.
XACML supports Attribute-Based Access Control (ABAC) and evaluation can be done with the additional data retrieved from Policy Information Point (PIP) which is defined by the XACML reference architecture.
Read the original article: A Basic Introduction to XACML