Which of the following BEST provides message integrity, sender identity authentication and

nonrepudiation?

A.
Symmetric cryptography

B.
Public key infrastructure (PKI)

C.
Message hashing

D.
Message authentication code

Explanation:

Public key infrastructure (PKI) combines public key encryption with a trusted third party to publish
and revoke digital certificates that contain the public key of the sender. Senders can digitally sign a
message with their private key and attach their digital certificate (provided by the trusted third
party). These characteristics allow senders to provide authentication, integrity validation and
nonrepudiation. Symmetric cryptography provides confidentiality. Mashing can provide integrity
and confidentiality. Message authentication codes provide integrity.