---
title: "SSL"
description: "SSL encrypts the connection between a browser and a server, today handled by TLS. Learn the role of the certificate, HTTPS and certificate types."
url: "https://nodea.io/en/glossary/ssl"
lang: "en"
updated: "2026-07-13"
---

# SSL

> SSL is a protocol that encrypts the connection between a browser and a server, today handled by its successor TLS; an SSL certificate confirms a site's identity and enables HTTPS.

**SSL** (*Secure Sockets Layer*) is a protocol that encrypts the connection between a user's browser and a server, protecting transmitted data from eavesdropping and tampering. Although the name SSL is still widely used, the protocol itself has been retired — modern encryption is handled by its successor, [TLS](https://nodea.io/en/glossary/tls). Even so, the terms "SSL certificate" and "SSL encryption" remain part of everyday language.

## How SSL works

At the heart of the mechanism is an **SSL/TLS certificate** — a digital file tied to a domain and issued by a trusted certificate authority (CA). When a browser connects to a site over [HTTPS](https://nodea.io/en/glossary/https), a handshake takes place: the server presents its certificate, the two sides agree on keys, and from that point all transmission is encrypted. The certificate serves two roles:

- **encryption** — data (passwords, card details, forms) is unreadable to third parties,
- **authentication** — it confirms you are connecting to the real owner of the domain, not an impersonating site.

Certificates differ by level of verification: from simple DV (proof of control over the domain), through OV, to extended EV. Wildcard and multi-domain certificates are also available.

## SSL in practice

An SSL certificate is now standard for every website — from a blog to an online store or banking. Without one, browsers display a "connection not secure" warning that deters users and harms reputation. Many hosting services offer free [Let's Encrypt](https://nodea.io/en/glossary/lets-encrypt-ssl-certificates) certificates with automatic renewal, so enabling HTTPS comes down to a few clicks. Thanks to [SNI](https://nodea.io/en/glossary/sni), a single server can serve many certificates for different domains on one IP address.

### Are SSL and TLS the same thing?

Colloquially people say SSL, but technically the SSL protocol is obsolete and retired — today connections are encrypted by its successor, TLS. The terms "SSL certificate" and "SSL encryption" persist in common use for historical reasons, though in practice they refer to TLS.

### Does an SSL certificate affect SEO?

Yes. Google treats HTTPS encryption as a ranking factor, and browsers flag sites without a certificate as "not secure". An SSL certificate therefore increases user trust, protects data and has a positive impact on rankings.

## Related

- [TLS](https://nodea.io/en/glossary/tls)
- [HTTPS](https://nodea.io/en/glossary/https)
- [Let's Encrypt (SSL certificates)](https://nodea.io/en/glossary/lets-encrypt-ssl-certificates)
- [SNI](https://nodea.io/en/glossary/sni)
- [HTTP](https://nodea.io/en/glossary/http)

---

Languages: [pl](https://nodea.pl/pl/slownik-pojec/ssl.md)  
Site index: [llms.txt](https://nodea.io/en/llms.txt)