Mandatory Access Control (MAC) is a security model that restricts access to resources based on predefined policies set by a central authority. In this system, users cannot change access permissions; instead, they must adhere to the rules established by the organization. This ensures that sensitive information is protected from unauthorized access, making it ideal for environments like government agencies or military operations. In a MAC system, each user and resource is assigned a security label, which determines their access level. For example, a user with a Top Secret clearance can access files labeled as Top Secret, but not those marked as Confidential or Unclassified. This structured approach helps maintain strict control over data and enhances overall security.