Understanding Certificate Authorities and How SSL Trust Works

Browsers don't inherently trust every SSL certificate — trust flows through a defined chain rooted in certificate authorities.

What a Certificate Authority Does

A CA verifies a certificate applicant's identity (or just domain ownership, for basic certificates) and digitally signs the certificate, vouching for its legitimacy.

The Chain of Trust

Browsers ship with a built-in list of trusted root CAs. A certificate is trusted if it can be traced back through a valid chain to one of these roots — break that chain, and browsers show a security warning.

Let's Encrypt as a CA

Let's Encrypt is itself a recognized, trusted certificate authority, issuing free certificates through the same chain-of-trust system as paid providers.

Further Reading

• SSL Certificates
• More Cybersecurity Guides
• Let's Encrypt