I am very familiar with OpenPGP but don't even use X.509 / S/MIME. I know that there are several classes for certificates (from email check to personal ID check). I would like to know how you determine the class of a certificate.
Is this information part of the CA signature? Or is that an organuzational feature only, using different root certificates for different classes? I noticed that one CA has different root certificates which have the class number in their name. Is there a real attribute for a root certificate which tells the user the class?