The University of SydneyPage 40Principle 8: The Three Types of Security Controls Are Preventative, Detective, and Responsive–A security mechanism serves a purpose by preventing a compromise, detecting that a compromise or compromise attemptis underway, or responding to a compromisewhile it is happening or after it has been discovered–For example,–Access to a bank’s safe or vault requires passing through layers of protection that might include human guards and locked doors with special access controls (prevention). –In the room where the safe resides, closed-circuit televisions, motion sensors, and alarm systems quickly detect any unusual activity (detection). –The sound of an alarm could trigger the doors to automatically lock, the police to be notified, or the room to fill with tear gas (response).