Re: [IETF-PKIX] OCSP Status Information on a Certificate

["David P. Kemp" <dpkemp@xxxxxxxxxxxxxx>]

> From: Paul Hoffman / IMC <paulh@imc.org>
>
> To the client, "not issued" is always more important than revoked or not
> revoked. We can put that in the OCSP spec.
>
> >As soon as OCSP clients are out there in any volume, there
> >are those who will seek to determine the client's behavior in fringe cases.
>
> I fully agree. That's why I'm I don't think that issued/not issued should
> be a MAY: I think it has to be a MUST. We can be sure that some clients
> will blow the comparison unless they are always told whether or not the
> cert was even issued.


I disagree that an Issued bit should be a MUST.  For that matter, I
don't see that it even needs to be a MAY in OCSP, but others seem to
want it for some reason.

If you have a certificate for which the signature verifies, you have
prima facie evidence that:
  1) the certificate was issued, or
  2) the CA's private key was compromised, or
  3) the signature algorithm is broken.
In the latter two cases, all bets are off and OCSP isn't going to
help -- why would you trust a signed OCSP response any more than a
signed certificate?
In the first case, you know the answer before you even ask the
question.

If you have a certificate for which the signature does not verify,
what are you going to do with it, regardless of OCSP's claim that
it has or has not been issued?

And if you don't have a certificate and are just trolling the OCSP
server by issuer/serial, subject name, or some other search criteria,
why should it feel obliged to disclose which guesses are valid?

Dave Kemp