CIA - confidentiality, integrity, availability
CIA triad, confidentiality, integrity, availability, is the three-fundamentals in security principle.
Confidential ensures the data or information is only accessible by authorised personnel only.
Integrity ensures the data is not tampered or destroyed by unauthorised activity.
Availability ensure the data or services are accessible by authorised personnel at any time.
When a security incident happened, you can be sure one or more of these principles are violated.