Glossary

HTTPS / TLS

HTTPS is HTTP over TLS encryption. It protects data from interception (man-in-the-middle attacks) and confirms you are communicating with the real server, not an impostor. Without HTTPS, browsers mark a site as "not secure" and SEO rankings suffer.

How TLS works (simplified)

The server sends a TLS certificate (signed by a trusted CA)
The client verifies the signature and generates a symmetric session key
All subsequent communication is encrypted with that key

Certificates

Let's Encrypt — free certificates with automatic renewal via Certbot
DV / OV / EV — validation levels: domain only, organisation, or extended verification

HTTP Strict Transport Security

The Strict-Transport-Security header prevents the browser from ever accessing the site over plain HTTP — even if the user types http:// manually.