1. Access control based on access rights granted by the System Security Officer. Note: Normally enforced by reference to security clearances of subjects and security classes of objects in accordance with the rules specified in the System Security Policy. 2. A means of restricting access to objects based on the sensitivity (as represented by a label) of the information contained in the objects and the formal authorization (i.e., clearance) of subjects to access information of such sensitivity. 3. A means of restricting access to objects based on their MAC labels and the use of the implementation-defined dominate operator. The restrictions are mandatory in the sense that they are always imposed by the system, while discretionary access control is imposed at the discretion of the object owner.