What is the main purpose of the Online Certificate Status Protocol (OCSP)?

The main purpose of the Online Certificate Status Protocol (OCSP) is to provide real-time verification of the status of digital certificates without the need to download an entire Certificate Revocation List (CRL) from the Certificate Authority (CA). OCSP allows clients to query a CA to check whether a specific certificate is still valid or has been revoked.

In detail, when a client needs to verify a certificate, it sends an OCSP request to the OCSP responder provided by the CA. The responder checks the current status of the certificate and returns a response indicating whether the certificate is valid, revoked, or unknown. This protocol significantly enhances efficiency and reduces the burden of maintaining and accessing large CRLs, which contain the status of many certificates but can become outdated quickly. Thus, the OCSP serves as a lightweight and timely solution for digital certificate status checks, ensuring secure communications in real-time.

The other options do not align with the operational intent of OCSP. Revoking digital certificates is indeed a function of a CA, but OCSP does not perform this action directly; rather, it checks for the status of revoked certificates. Creating new digital certificates and storing certificates on a server are also outside the primary functionality of OCSP, which is solely focused on querying