What will be the server response if the certificate serial number is not found in the CRL?

• A. REVOKED
• B. GOOD
• C. UNKNOWN
• D. EXPIRED

Answer: (B)

When a certificate is checked against a Certificate Revocation List (CRL) and the serial number corresponding to that certificate is not found, it indicates that the certificate is still considered valid and has not been revoked by the issuing Certificate Authority (CA). In this scenario, the server response would be "GOOD," signifying that the certificate is valid and can be trusted for the current session or operation.

The relevance of the CRL in this case is to ensure that only certificates that are still active and safe to use are trusted in secure communications. A serial number missing from the CRL means there is no record of revocation, supporting the conclusion that the certificate remains valid. This helps maintain the integrity and trustworthiness of communications and transactions that rely on SSL/TLS certificates.

Other options such as "REVOKED," "UNKNOWN," and "EXPIRED" would imply different statuses that do not apply when a non-revoked certificate's serial number is not present on the CRL. "REVOKED" would suggest the certificate is no longer valid, while "UNKNOWN" could indicate that the status is not clear due to various reasons. "EXPIRED" indicates that the validity period of the certificate has lapsed, independent of the revocation