What are SSL certificates?

What is an SSL/TLS connection?

An SSL connection — these days better known as TLS (Transport Layer Security) — is an encrypted connection between a website and the visitor's browser. Thanks to this security layer, data can be sent safely without third parties intercepting or manipulating it along the way.

You recognise a secure connection by the use of https:// in the URL. In modern browsers a secure connection is usually no longer shown prominently. The padlock icon is often subtle or even gone. What does stand out is when a website is not secure: browsers then show explicit warnings, such as "Not secure" in the address bar, or even block access to the website altogether.

Why do SSL/TLS matter?

Without encryption, sensitive data such as passwords, personal details and payment information travels across the network unencrypted. That makes it vulnerable to so-called man-in-the-middle attacks, where bad actors can intercept the traffic — on public wifi networks or shared corporate networks, for example.

An SSL/TLS certificate prevents this by encrypting the traffic between visitor and server. Only the sender and the recipient can read the data. That not only protects your visitors' privacy, it also strengthens trust in your website.

On top of that, the General Data Protection Regulation (GDPR) obliges organisations to secure personal data adequately. An encrypted connection is always required for that.