Which of the following is the MOST reliable sender authentication method?

A.
Digital signatures

B.
Asymmetric cryptography

C.
Digital certificates

D.
Message authentication code

Explanation:
Digital certificates are issued by a trusted third party. The message sender attaches the certificate and the
recipient can verify authenticity with the certificate repository. Asymmetric cryptography, such as public key
infrastructure (PKl), appears to authenticate the sender but is vulnerable to a man-in-the-middle attack. Digital
signatures are used for both authentication and confidentiality, but the identity of the sender would still be
confirmed by the digital certificate. Message authentication code is used for message integrity verification.