thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Security Fundamentals & Crypto · Foundational

Certificate Authority

Trusted entity that verifies identities and issues, signs, and revokes digital certificates.

Definition

CAs may be public (trusted by browsers and operating systems) or private (trusted only within an organization). Public CAs must follow the CA/Browser Forum Baseline Requirements and undergo audits. A compromised CA can issue fraudulent certificates for any name, as happened with DigiNotar in 2011.

Example

Let's Encrypt is a public CA that issues free domain-validated certificates via ACME.

Exam tip

Use a private/internal CA for internal hostnames; public CAs are needed for internet-facing sites.

Don't confuse it with

Related terms