Why is certificate validation during a TLS handshake important?

• A. It validates chain of trust and prevents MITM
• B. Encrypts the entire session data
• C. Guarantees anonymity of the user
• D. Eliminates all DNS spoofing threats

Answer: (A)

Certificate validation checks that you are speaking to a legitimate server, not an imposter, before any sensitive data is exchanged. In the TLS handshake, the server presents a certificate that should chain up to a trusted root authority. The client verifies the chain, confirms the certificate is currently valid (not expired or revoked), and ensures the certificate’s domain matches the site you’re visiting. When these checks pass, both sides derive a shared session key to encrypt and protect the data for the rest of the session. This authentication through a trusted certificate is what prevents a man-in-the-middle from successfully impersonating the server. Encrypting the session is a result of that handshake, but its primary purpose is to prove identity and establish trust, not anonymity. It doesn’t by itself eliminate DNS spoofing, which is a separate risk that still requires other protections.