Which statement best describes mutual TLS?

• A. The client and server authenticate each other using certificates.
• B. Only the client authenticates to the server using a password.
• C. TLS with no certificates at all.
• D. Authentication is performed using username and password without certificates.

Answer: (A)

Mutual TLS is when both sides in a TLS connection prove their identities with certificates during the handshake. The server presents a certificate to prove its identity, and the client verifies it. In mutual TLS, the client also presents its own certificate to the server, and the server verifies the client’s certificate. This two-way certificate-based authentication creates trust in both directions and secures the channel.

This is different from standard TLS, where only the server is authenticated and there’s no requirement for the client to present a certificate. Password-based authentication or anonymous TLS (no certificates) do not provide this same bidirectional, certificate-driven trust, which is why they don’t describe mutual TLS.