When you visit a website and see a padlock icon in the address bar alongside 'https://', that means the site has an SSL certificate. SSL (Secure Sockets Layer) — more accurately called TLS (Transport Layer Security) today — is the security protocol that encrypts data between a website's server and a visitor's browser.
What Does an SSL Certificate Actually Do?
An SSL certificate encrypts the data transmitted between a visitor's browser and the web server. Passwords, payment details, form submissions, and any other information cannot be intercepted or read by a third party.
Without SSL, data travels as plain text over the network. On a public Wi-Fi connection, this data could theoretically be captured by anyone monitoring the traffic. Modern browsers flag non-SSL (HTTP) sites as 'Not Secure', which causes most visitors to leave immediately.
How Does SSL/TLS Work?
When a browser connects to an HTTPS site, it performs a 'TLS handshake' with the server. The server presents its SSL certificate; the browser verifies that a trusted Certificate Authority (CA) signed it. If valid, an encrypted session is established and all exchanged data becomes unreadable to anyone intercepting it in transit.
This entire process takes milliseconds and is completely invisible to the user.
Types of SSL Certificates: DV, OV, EV
SSL certificates are categorised by their level of identity verification:
- DV (Domain Validation): The most common type. Only domain ownership is verified. Issued within minutes; available for free via Let's Encrypt. Suitable for blogs, brochure sites, and informational pages.
- OV (Organisation Validation): The company's legal existence and identity are verified by the CA. Provides a stronger trust signal; recommended for corporate and B2B websites.
- EV (Extended Validation): The most rigorous verification process. Standard for banks and major e-commerce platforms.
SSL and SEO: Why Google Cares About HTTPS
Google announced HTTPS as a ranking signal in 2014. Sites without SSL are disadvantaged in search rankings and suffer elevated bounce rates from browser security warnings.
As of 2026, SSL is the baseline expectation for any public website. CDN-based hosting platforms such as Vercel, Cloudflare, and Netlify provision SSL certificates automatically at no extra cost, with no manual configuration required.
How to Get an SSL Certificate
The most common route to free SSL is Let's Encrypt, a non-profit Certificate Authority. CDN platforms automatically install and renew Let's Encrypt certificates — no action required on your part.
Paid certificates from CAs such as DigiCert, Sectigo, and Comodo range from $10 to $300+/year. For most small business websites, a free DV certificate is technically equivalent in encryption strength to paid alternatives — the difference lies only in the level of identity verification, not security.