Mutual authentication ensures that

• A. Only the Client Is Authenticated
• B. The Client Authenticates the Server Only
• C. Both Parties Authenticate Each Other
• D. No Authentication Occurs

Answer: (C)

Mutual authentication means both sides prove who they are to each other. In a secure connection, the server verifies its identity to the client so the client isn’t talking to a counterfeit server, and the client verifies its identity to the server so the server isn’t talking to an unauthorized party. This two-way verification prevents impersonation and protects against man-in-the-middle attacks, because neither side will establish a trusted channel until both identities are confirmed.

A common way this is achieved is mutual TLS, where the server presents a certificate that the client validates, and the client presents a certificate that the server validates. Once both verifications succeed, a secure channel is established, ensuring confidentiality and integrity of the communication.

If only the client were authenticated, the client could be deceived about who it’s connecting to. If only the server were authenticated, the client could be impersonated by an attacker. If no authentication occurs, there’s no trust at all.