Digital Lexicon Hub

A digital certificate issued by a certificate authority that binds a domain name to a public key, enabling encrypted HTTPS connections.

Expired or misconfigured certificates trigger browser warnings that stop visitors, break integrations and APIs and interrupt form submissions, so renewal automation and clear ownership are basic website operations.

A site uses an ACME client to obtain certificates from Let's Encrypt through the HTTP-01 challenge, renews them automatically every 60 days, redirects HTTP to HTTPS with a 301 and sends an HSTS header.

A certificate proves control of a domain, not that the business behind it is trustworthy. Maximum lifetimes are shrinking, which makes manual renewal risky, and a valid certificate does not protect a site from flaws in its own code.

Despite the common name, certificates are now used with TLS 1.2 or 1.3; SSL versions are obsolete. An X.509 certificate holds the domain names, public key, validity dates and the issuing authority's signature, chained to a root trusted by browsers. In the TLS handshake the server presents it so the client can authenticate the server before Encryption in Transit begins. The CA/Browser Forum approved a phased cut in maximum validity from 398 days to 47 days between March 2026 and March 2029.