Which statement defines Integrity?

• A. Granting permissions after authentication.
• B. Verifying identity of a user or system.
• C. Ensuring data is not altered without authorization.
• D. Ensuring data is only accessible to authorized users.

Answer: (C)

Integrity is about trustworthiness of data: it means information remains accurate and unchanged by unauthorized parties, and any legitimate changes are detectable and authorized. This is achieved with mechanisms like hashes, checksums, digital signatures, message authentication codes, and audit trails, which help ensure that tampering is detectable and prevent improper modifications. Therefore, the statement that describes data not being altered without authorization best captures integrity. The other options describe authentication (verifying identity), authorization (granting permissions), and confidentiality (restricting access), which are different security properties.