Final answer:
Digital certificates are sometimes revoked for various reasons. This is important to ensure the credibility of the certificates and the entities using them. Revocation mechanisms such as CRLs and OCSP help verify the revocation status of certificates.
Step-by-step explanation:
Digital certificates are used to verify the authenticity and integrity of data transmitted over the internet. However, there are situations where a certificate needs to be revoked. This is necessary when the certificate has expired, the private key has been compromised, or the entity no longer needs the certificate.
Revocation mechanisms, such as Certificate Revocation Lists (CRLs) or Online Certificate Status Protocol (OCSP), allow for the checking of a certificate's revocation status before relying on it. CRLs are periodically distributed lists of revoked certificates, while OCSP provides real-time revocation information. These mechanisms ensure that certificates issued by trusted certificate authorities are still valid and can be trusted.