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, access is determined by the classification of information and the user's security clearance level. This ensures that sensitive data is only accessible to authorized individuals. In MAC, data is often labeled with security levels, such as Top Secret, Secret, and Confidential. Users are assigned corresponding clearances, which dictate their ability to access or modify the data. This model is commonly used in government and military environments to protect classified information.