Which system is used for managing public keys and digital certificates?

• A. PKI (Public Key Infrastructure)
• B. Certificate Authority (CA)
• C. Registration Authority (RA)
• D. Certificate Revocation List (CRL)

Answer: (A)

Public Key Infrastructure (PKI) is the framework used to manage public keys and digital certificates throughout their lifecycle. It provides the processes, policies, and roles needed to issue, distribute, store, validate, and revoke certificates, tying a public key to a verified identity so others can trust communications. The main components work together: a certificate authority issues and signs certificates, a registration authority helps verify identities, and mechanisms like certificate revocation lists (or OCSP) revoke certificates that should no longer be trusted. Without PKI, there isn’t a coherent trust model to reliably bind identities to keys; the other options are parts of PKI rather than the overarching system itself.