TLS handshake certificate chain: who verifies the server identity and how?

• A. Client uses a trusted certificate store to verify the server's certificate chain presented by the server during handshake.
• B. Server validates the client's certificate chain only.
• C. The network router validates the chain; clients do nothing.
• D. Certificates are not used in TLS handshake.

Answer: (A)

The client verifies the server’s identity by validating the server’s certificate chain against a trusted store of root certificates. During the TLS handshake, the server sends its certificate chain, and the client checks that each certificate is properly signed by the next certificate up to a root CA that the client trusts. It also confirms that every certificate in the chain is currently valid (not expired or revoked) and that the server’s hostname matches the certificate’s subject or SAN. If all of these checks pass, the client is confident in the server’s identity and the handshake proceeds. The server does not perform this verification for the client in standard TLS; that would only happen if mutual TLS with client certificates is configured.