Certificate Revocation Lists

Last night's Tip discussed the use of certificate authorities to authenticate web site owners, and encrypt communications. Certificate authorities do not remain valid indefinitely. Expired certificates will generate an error message. Certificate authorities that have been revoked for some other reason will be put on a Certificate Revocation List (CRL). This is an example of an error message you'll see in a browser if a CA has been put on a CRL.

Some CAs on a CRL will only be on hold, and are not necessarily permanently revoked.

Digital certificates will be placed on a CRL when public keys have been compromised, a certificate is believed to be a fake, the issuer of the CA is compromised, or a web site owner no longer owns a server or domain name.