CyberGuard dictionary / Cryptography
Certificate Authority
Also known as CA
An organization or service that issues and signs digital certificates under a trust model.
In simple terms
A certificate authority helps a browser check which public key belongs to a website.
Technical explanation
In the Web PKI, trusted authorities validate domain control and sign certificates; browsers verify chains and identity names.
A CA issues certificates as part of a trust chain that a browser evaluates against the requested hostname and validity period. Certificate transparency and revocation mechanisms add visibility but are not perfect guarantees.
Examples in practice
A browser checks a website’s TLS certificate against trusted issuing authorities.
A site presents a certificate for a different hostname, so the browser warns before sending credentials. The operator checks the certificate deployment and DNS rather than asking users to bypass the warning.
Why it matters
Certificate validity is necessary for many secure connections but does not prove a site is benign.
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Sources and further reading
Published 2026-10-15 · Last updated 2026-10-15 · CyberGuard editorial content. Source links provide context; they do not imply endorsement.