CRLs are lists of certificates that have been revoked by the issuing CA and should not be trusted by any entity. CRLs contain the serial number of the certificate that has been revoked, the date and time of revocation, and the reason for revocation. Revoked certificates are automatically placed on the CRL by the CA and the CRL is updated periodically. CRLs can be exported through various methods, such as HTTP, LDAP, or SCEP. Each local CA has its own CRL that is specific to its issued certificates. Reference: https://docs.fortinet.com/document/fortiauthenticator/6.4/administration-guide/372408/certificate-management/372413/certificate-revocation-lists