CISSP Practice Question: An organization requires proof that a sensitive document was signed by a…

Correct Answer: A. Non-repudiation

Explanation (CISSP Manager Logic):

Non-repudiation ensures that the sender of a message or signer of a document cannot later deny having sent or signed it. It combines authentication of the identity with assurance of integrity to provide legal-strength proof of an action.

By implementing non-repudiation, you:

• Ensure the authenticity of the source (Identity)
• Guarantee the integrity of the data (No alterations)
• Provide accountability that is defensible in a legal or audit context

While the other options are relevant, they fall short because:

• B: Availability focuses on the readiness and accessibility of the data, not its origin or integrity.
• C: Authentication only proves identity at a point in time; it does not inherently prove that a specific document was signed or prevent later denial.
• D: Confidentiality ensures the document remains secret but does not provide proof of who signed it or that it wasn't changed.

Think like a manager:

Management must look for the control that provides the highest level of accountability. Non-repudiation is the strategic choice when the goal is to bind an identity to an action in an undeniable way.