What information is required for a certificate to be correctly identified in an OCSP request?

When making an Online Certificate Status Protocol (OCSP) request, the crucial piece of information needed to correctly identify a certificate is its serial number. The serial number is a unique identifier assigned by the Certificate Authority (CA) to each certificate it issues. This ensures that even if two certificates are issued to different entities or have identical other attributes, the serial number will uniquely differentiate them.

The OCSP request is designed to check the revocation status of a particular certificate. By including the certificate's serial number in the request, the OCSP responder can precisely locate the corresponding record in its database and provide an accurate status—whether the certificate is valid, revoked, or unknown. This mechanism promotes effective and efficient validation of the certificate during secure communications.

Other options do not serve as unique identifiers for the certificate in the context of OCSP requests. While the certificate holder's name, issue date, and public key are important for other aspects of certificate management, they are not necessary for accurately identifying the certificate in an OCSP context. Hence, without the serial number, the identification and verification process cannot be performed reliably.