Subject: Re: Computation of issuerKeyHash in OCSP

From: [email-masked] (Peter Gutmann)
Date: Tue, 13 Mar 2001 15:28:27 (NZDT)

Dr S N Henson <[email-masked]> writes:

>I was getting valid responses from the responders I'd tried which suggests
>that either they are ignoring the issuerKeyHash or they are also ignoring the
>number of unused bits.

If I could find a responder to get a reply from (the usual suspects seem to be
unreachable/dead at the moment) I'd like to test this to see whether you can
submit a broken issuerKeyHash, from earlier testing against one of them I found
that you did have to get the hash right (that's how I did the trial-and-error
discovery of what was required, I figured the issuer name hash couldn't be
wrong and started playing with hashing/not hashing bits of the key until I
didn't get an "unknown" response any more).  OTOH the issuerKeyHash isn't
absolutely necessary since (depending on the implementation) you can get the
same information from the issuerNameHash.

I've also got another question about the spec which comes from playing with
various responders, the implementation requirement that "Certificates SHOULD
NOT contain an AIA extension specifying the responder URL.  If they do contain
a responder URL, this MUST NOT match the actual responder URL" seems to have
been left out of the draft.  Is this an unwritten convention followed by
implementors which is worth documenting?

Peter :-).

---

From: Rich Salz <[email-masked]>
Date: Mon, 12 Mar 2001 22:01:55 -0500

> implementors which is worth documenting?

If you came looking for an argument, you'll have to go down the door to
the CA people.  The OCSP responder people rarely create certificates --
too frightening.  And while it's tempting for ORP's to move their URL
about arbitrarily, it's not common.
	/r$