Certificate Revocation List (CRL)

A Certificate Revocation List (CRL) is a list maintained by a certificate authority that details digital certificates (like online ID cards) that are no longer trustworthy. Certificates can be revoked before their expiration date due to security concerns or compromise. When a device or application wants to verify a certificate’s validity, it checks the CRL to ensure it hasn't been revoked. This process helps maintain trust and security in digital communications by preventing the use of certificates that are no longer considered secure or valid.