In a MAC model, which objects and subjects have a label?

In a Mandatory Access Control (MAC) model, both objects and subjects are assigned labels that define their security level. This labeling is crucial for enforcing access controls based on the classifications and clearances that determine how and when data can be accessed or modified.

In MAC, the security label of a subject (such as a user or a process) typically indicates the user's clearance level, while the labels on objects (like files, data, resources) reflect their classification level. Access decisions are based on these labels, ensuring that users can only interact with objects that are at or below their own security level, thereby maintaining a high degree of security and preventing unauthorized access.

This dual labeling system is fundamental to the MAC model, as it enables an organization to implement strict access control policies that safeguard sensitive information and enforce compliance with regulatory requirements. Hence, the correct response emphasizes the presence of labels on both subjects and objects, as this dual labeling is central to the mechanics of protecting data in a MAC framework.