Access control a is way of limiting access to a system or to physical or virtual resources. In computing, access control is a process by which users are granted access and certain privileges to systems, resources or information.
In good old day access control systems, users must present credentials before they can be granted access. In current physical systems, these credentials may come in many forms, but credentials that can't be transferred in order to provide a heavy security.
Entitlement management is the process granting privalages to resources or uses, after fine-grain authentication for controling access of users. XACML is an OASIS standard that describes both a policy language and an access control decision request/response language (both written in XML).
Therefore, following topics will discuss how Entitlement Management and XACML useful in access control.