How to check a digital certificate?
- by StackedCrooked
I have extracted a certificate from a cable modem. Now I want to verify if this certificate is valid. If I understand correctly, the verification process consists of having the issuer sign the subject's public key and then comparing the result with the subject's signature. This signing process is done using the issuer's private key, which nobody but the issuer has access to. So even if I have both certificates on my PC, there is no way for me to verify the subject's validity. From this I can only conclude that the verification must be implemented as a remote service.
The problem is that I don't know what remote service I need to access to verify this certificate. The issuer is "AVM GmbH Cable Modem Root Certificate Authority". How can I find the webservice for verification? Is there standard lookup mechanism for this?