Non-Repudiation assures that sender of the message cannot deny the validity of the message sent.

• A. Attestation
• B. Non-Repudiation
• C. Privacy
• D. Confidentiality

Answer: (B)

Non-repudiation is the ability to prove who sent a message and that it hasn’t been altered, so the sender cannot later deny having sent it. This is achieved with cryptographic signatures and verifiable evidence like timestamps and logs tied to the message, giving strong accountability for the origin and integrity of communications.

Attestation deals with proving claims about a system or component’s state, not specifically proving who sent a message. Privacy focuses on protecting sensitive information from disclosure, and confidentiality is about keeping data from being read by unauthorized parties. While related, none of these ensure that the sender cannot deny sending the message as non-repudiation does.

So, the best answer is non-repudiation.