Which element of Public Key Infrastructure (PKI) verifies the applicant?

The Certificate Authority issues, signs, and manages digital certificates but relies on the RA to perform applicant identity verification.

A Validation Authority provides certificate status information to relying parties - typically through OCSP - to confirm whether a certificate is valid or revoked.

The Registration Authority acts as an intermediary between the applicant and the Certificate Authority, performing identity verification and vetting applicants according to defined policies. The RA collects and validates applicant credentials but delegates the actual certificate signing to the CA. This separation of duties allows the CA to remain offline and secure while the RA handles applicant interaction.

Verification Authority is not a standard or recognized component in PKI terminology; it does not correspond to a defined PKI role.