Final answer:
A Certificate Revocation List (CRL) is a list of digital certificates that have not expired but should be considered invalid. It is used to maintain and distribute information about revoked certificates. A CRL is published by a Certificate Authority (CA).
Step-by-step explanation:
A list of serial numbers of digital certificates that have not expired but should be considered invalid is called a Certificate Revocation List (CRL). A CRL is a mechanism used in public key infrastructure (PKI) to maintain and distribute a list of digital certificates that have been revoked or should no longer be trusted.
A CRL is published by a Certificate Authority (CA), which is responsible for issuing and managing digital certificates. It contains information such as the serial numbers of revoked certificates, the date of revocation, and the reason for revocation.
By checking the serial numbers of digital certificates against the CRL, clients can verify if a certificate should be considered invalid even if it has not yet expired.