Understanding the SSL/TLS Handshake Process

The SSL/TLS handshake establishes encrypted communication between browsers and servers through a complex verification process. During this handshake, the server presents its certificate to prove its identity. The browser then validates this certificate against several criteria: checking the certificate authority's signature, verifying the domain name matches, confirming the certificate hasn't expired, and ensuring the certificate chain leads to a trusted root.

When any step in this process fails, browsers immediately halt the connection and display warning messages. Modern browsers have become increasingly strict about certificate validation, rejecting certificates with weak encryption, outdated protocols, or any anomalies in the trust chain. This heightened security stance means even minor certificate issues can completely block site access.