PKI
In plain terms
The framework managing keys and certificates for secure trust.
Going deeper
Public Key Infrastructure encompasses the policies, authorities, and processes that issue, distribute, and revoke digital certificates. It underpins encrypted, authenticated communication.
Under the hood
Includes CAs, registration, revocation (CRL/OCSP), and key management; the trust backbone of the secure web.
Examples
TLS trust, enterprise certificates, smart cards, code signing, CA hierarchies.
Think of it like...
Like the whole passport system, issuing offices, verification, and revocation, that makes IDs trustworthy.