Expired SSL certificates primarily affect which aspect of an SSL connection?

• A. The trust validation during handshake
• B. The TCP window size
• C. The DNS resolution
• D. The cipher negotiation

Answer: (A)

Expired SSL certificates affect trust validation during the TLS handshake. When a client connects, it receives the server’s certificate and must verify it’s issued by a trusted CA, matches the server’s hostname, and is within its validity period. If the certificate is expired, the client marks it as invalid and stops the handshake, preventing a trusted secure connection. The other options don’t rely on the certificate’s validity: TCP window size is a TCP transport parameter, DNS resolution happens before TLS, and cipher negotiation, while part of the handshake, isn’t driven by certificate expiry.