What does the Certificate Revocation List (CRL) contain?

The Certificate Revocation List (CRL) specifically contains a list of digital certificates that have been revoked. This list is vital for managing the security of digital communications, as it provides information about certificates that were previously issued but can no longer be trusted due to a variety of reasons, such as key compromise, change of affiliation, or other security concerns. When systems validate a certificate, they often check the CRL to ensure the certificate has not been revoked before proceeding with any secure communication.

While the other options mention lists that might be relevant in certificate management, they do not accurately describe the function of the CRL. A list of valid certificates, a list of issued certificates, or a list of certificates pending approval do not pertain to the concept of revocation, which is the primary focus of the CRL. Understanding this distinction is crucial for maintaining the integrity and trustworthiness of digital security systems.