HTTPS is the secure version of HTTP. It encrypts everything between a visitor's browser and your website, so passwords, forms and payment details cannot be read or changed on the way. The encryption is provided by TLS, still commonly called SSL, and is tied to a certificate that proves the site's identity.
Key terms
- SSL: the original protocol, now obsolete; the name stuck.
- TLS: the modern protocol (TLS 1.2 and 1.3).
- Certificate: a file signed by a certificate authority (CA) that binds a public key to your domain.
- Private key: the secret half that stays on the server.
How the HTTPS handshake works
- The browser connects and says which TLS versions and ciphers it supports.
- The server replies with its certificate.
- The browser checks that a trusted CA signed it, that it covers the domain and that it has not expired.
- Both sides agree on a one-time session key using the key exchange.
- All further traffic is encrypted with that session key. With TLS 1.3 this takes a single round trip.
Types of certificates
| Type | Validates | Typical use |
|---|---|---|
| DV (domain validated) | Control of the domain only. | Most websites. AutoSSL and Let's Encrypt issue these free. |
| OV (organisation validated) | Domain plus company identity. | Business sites wanting the company in certificate details. |
| EV (extended validation) | Strict company checks. | Banks, large brands (browsers no longer show a green bar). |
| Wildcard | All subdomains of one level: *.example.com. | Many subdomains. |
| Multi-domain (SAN) | Several names in one certificate. | Groups of sites. |
Encryption strength is the same for all types; they differ in identity checks. See free vs paid SSL.
Why every site needs HTTPS
- Browsers mark HTTP pages as Not secure.
- Search engines prefer HTTPS pages.
- HTTP/2 and HTTP/3 speed-ups require it.
- Logins and forms are protected from eavesdropping on public Wi-Fi.
On MdmHost cPanel hosting, AutoSSL issues and renews free certificates for every domain automatically. Then force HTTPS so visitors always use the secure version.