CRL
Certificate Revocation List
Digital Certificates are only valid for a specified period; if, after this period, they are not renewed by the owner they are revoked. Revocation may also be applied to certificates that may have been compromised. All revoked certificates are listed and may be viewed through the CA (Certification Authorities) web site. These lists are issued on a regular basis by the CA, and prior to a dialogue being established between end parties this list should be checked to ensure the integrity of the parties involved in the communication.