How TLS certificates secure the internet.
A TLS certificate proves a website is who it claims to be and enables an encrypted connection between browser and server. It’s the technology behind the padlock — and HTTPS itself.
A TLS certificate (often called an SSL certificate) is a digital file that binds a public key to a domain name. It lets a browser verify a server’s identity and negotiate an encrypted session, turning HTTP into HTTPS.
From handshake
to encrypted session.
The browser connects and the server presents its TLS certificate.
The browser validates the certificate chain up to a trusted root.
Both sides agree on session keys using the certificate’s public key.
All data flows encrypted — this is HTTPS in action.
What’s inside a
TLS certificate.
SSL is the deprecated predecessor; TLS is its modern, secure successor. The term “SSL certificate” persists, but the protocol is TLS.
Subject, issuer, validity dates, public key, and signature — the core attributes a browser inspects.
Subject Alternative Names let one certificate cover multiple domains and hostnames.
A wildcard certificate (*.example.com) secures every subdomain under a domain.
A valid certificate is
only valid for so long.
Validity periods are shrinking toward 47 days.
An expired cert makes browsers refuse the connection.
One expired multi-domain cert can break many sites.
A wildcard’s expiry takes down every subdomain at once.
Old algorithms and short keys must be rotated.
Continuous discovery and auto-renewal keep HTTPS up.
TLS certificates,
answered.
Related topics
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