What Happens When a Certificate is Revoked?

Revoking a certificate means to invalidate or cancel it. When a certificate is revoked, it is no longer considered valid or trusted by the Certificate Authority (CA) that issued it, and any parties that rely on the certificate for authentication or encryption should stop using it.

Revocation can be done for various reasons, such as:

1. Key compromise: If the private key associated with the certificate is compromised, the certificate may be revoked to prevent unauthorized access to the system or data.
2. Certificate holder's request: The certificate holder may request the CA to revoke the certificate if they no longer need it or if they discover any security issues related to the certificate.
3. Certificate expiration: Certificates have a limited lifespan, and they will be automatically revoked after they expire.
4. Security concerns: If the CA identifies any security concerns related to the certificate, such as a vulnerability in the issued certificate or a compromise of the CA's own systems, they may revoke the certificate to protect users.

When a certificate is revoked, the CA will typically place it on a Certificate Revocation List (CRL) that lists all the revoked certificates. This allows clients and other parties to check the CRL before trusting a certificate, and ensures that they do not use a revoked certificate.