Which of the following security services protects against repudiation?

Concept

A security service addresses a defined security objective. Under the OSI security architecture (ITU-T X.800), authentication verifies identity, access control restricts authorized use, data integrity protects against unauthorized modification, and non-repudiation supplies evidence that prevents a party from successfully denying an action.

Application

Repudiation means that a party later denies involvement in sending, receiving, or authorizing something. The service whose function is to provide proof of origin or delivery is non-repudiation, so it directly addresses the threat named in the question.

Contrast

• Access control governs permission to use a resource; its objective is authorization.

• Authentication verifies a claimed identity; its objective is identity assurance.

• Data integrity protects data from unauthorized alteration; its objective is preserving the data's state.

Result

Therefore, the security service that protects against repudiation is non-repudiation.