Digital signatures provide which combination of properties?

• A. Confidentiality
• B. Message Authentication
• C. Message Integrity
• D. Both Message Authentication and Message Integrity

Answer: (D)

Digital signatures mainly establish who sent the message and that its content hasn’t been altered. By signing a hash of the message with a private key, the signer provides origin authentication, and anyone with the signer’s public key can verify that the signer is indeed the source. At the same time, because the signature covers the message’s contents, any tampering would cause the verification to fail, ensuring integrity. These tools do not inherently hide the message’s content from others, so confidentiality isn’t guaranteed by the signature alone. That’s why the best answer is the combination of both authentication and integrity, with the caveat that non-repudiation is often an additional property of digital signatures.