What is mandatory access control?

Mandatory Access Control (MAC) is a type of access control where the operating system constrains the ability of a subject (user or process) to access or generally perform some operation on an object (file, memory segment, network resource). Unlike Discretionary Access Control (DAC), users cannot override these policies. MAC is commonly used in systems where security is paramount, such as military and government systems, to enforce strict data confidentiality and integrity.