XACML, or eXtensible Access Control Markup Language, is a declarative access control policy language implemented in XML. In cloud computing, XACML is used to define security policies that control access to resources.

• XACML provides a standardized way to define and enforce access control policies, improving security and compliance.
• It's also flexible and extensible, allowing for complex access control policies that can adapt to changing business needs.

XACML works by providing a syntax for defining access control policies in XML. These policies can then be enforced by an XACML-compliant access control system.

• XACML policies can define who can access what resources, under what conditions.
• The policies can be enforced at runtime, providing dynamic access control that can adapt to changing conditions.

A cloud service provider, CloudServe, uses XACML to define and enforce access control policies for their cloud services. This allows them to control who can access their services, under what conditions, improving their security and compliance.