When both parties prove their identities to the other, this is called

• A. Mutual Authentication
• B. Symmetric Authentication
• C. Authentication
• D. Dual Authentication

Answer: (A)

Mutual authentication is when both parties prove who they are to each other before proceeding. This bidirectional verification builds trust in both directions and helps prevent impersonation and man-in-the-middle attacks, since each side validates the other’s identity, often using certificates, tokens, or challenge-response proofs. For example, in a TLS handshake, the server can authenticate itself to the client, and the client can also present credentials to authenticate itself to the server. This is different from one-way authentication, where only one side proves its identity.