Digital signatures provide which of the following?

• A. Message Authentication
• B. Message Integrity
• C. Both Message Authentication and Message Integrity
• D. Neither

Answer: (C)

Digital signatures bind the sender’s identity to the message and ensure the content hasn’t been altered after signing. When the signer uses their private key to create the signature on the message (or its hash), anyone with the signer’s public key can verify that the signature was created with the corresponding private key and that the message is intact. This provides authenticating the source (the message came from the claimed sender) and ensuring integrity (the message hasn’t been tampered with since signing). It’s worth noting that, unlike encryption, a digital signature does not by itself hide the message’s contents; its primary roles are authentication and integrity (and, implicitly, non-repudiation). That’s why the correct choice is that digital signatures deliver both message authentication and message integrity.