The fundamental information security principals include confidentiality, availability and which of the following?

Protecting data against unauthorized disclosure describes Confidentiality, the first principle of the CIA triad, not the third.

Integrity is the security principle that ensures data and systems are protected from unauthorized creation, modification, or deletion, preserving accuracy and trustworthiness. It is the third pillar of the CIA triad alongside Confidentiality and Availability. Controls such as hashing, digital signatures, access controls, and audit logs are used to enforce and verify integrity.

Attesting to the identity of a user describes Authentication or Non-repudiation, which are security concepts but not the third CIA triad principle.

Providing uninterrupted service to authorized users describes Availability, the second principle of the CIA triad, not the third.