Integrity is the principle that ensures the data is accurate and reliable and has not been tampered with or altered by unauthorized persons. Confidentiality is about keeping information secret and ensuring that it is accessible only to authorized individuals, while availability ensures that data and resources are available to those who should rightfully have access when needed. Authentication, on the other hand, is a process used to verify that someone is who they claim to be, but is not a principle of the CIA triad.