Certificate Authority
In plain terms
A trusted entity that issues and vouches for digital certificates.
Going deeper
A Certificate Authority verifies identities and signs certificates so others can trust that a public key is genuine. It anchors web trust.
Under the hood
Browsers ship with trusted root CAs; a compromised CA undermines trust broadly, hence strict scrutiny.
Examples
Let's Encrypt, DigiCert, root CAs, issuing TLS certs, trust chains.
Think of it like...
Like a passport office whose stamp others trust to confirm your identity.