Glossary / SSL
What is SSL?
SSL/TLS certificates and HTTPS
SSL, now properly called TLS, is the encryption that protects traffic between a browser and a website. A site with a valid certificate loads over HTTPS and shows a padlock.
Without encryption, anyone on the same network could read or change what passes between a visitor and your site, including passwords and form entries. TLS scrambles that traffic so only the two ends can read it.
A certificate proves the site really is the domain it claims to be. Certificates are issued by trusted authorities and expire, so they need renewing; many hosts do this automatically and for free.
Browsers warn visitors about sites without HTTPS, and search engines prefer secure pages, so every public site and app should use it.
Questions
Is SSL the same as TLS?
TLS is the newer version of SSL. People still say SSL out of habit, but modern sites use TLS.
Do I have to pay for an SSL certificate?
Usually not. Free certificates are widely available, and most hosting platforms issue and renew them automatically.