Subject: RE: delta-CRLs and NR

From: "Tom Gindin" <[email-masked]>
Date: Tue, 24 Apr 2001 14:49:40 -0400

The dispute resolver's point of view is indeed the critical one for
NR.  However, 2459 section 5.2.4 says that it only takes one delta CRL in
combination with its base CRL to give all the information in a full CRL
with the effective time of the delta.  Thus, the data to be checked during
dispute resolution would only need to consist of either a full CRL with
time after the document signature or of a delta CRL with such a time along
with its base CRL, as would the data which the RP or escrow holder need to
archive.  Thank you for your help on this, as I need to clarify some
wording in the techNR draft.

          Tom Gindin

"Michael Myers" <[email-masked]> on 04/24/2001 02:31:45 PM

To:   Tom Gindin/Watson/IBM@IBMUS
cc:   "David P. Kemp" <[email-masked]>, <[email-masked]>
Subject:  RE: delta-CRLs and NR

Tom,

Perhaps I should have used the term "dispute resolution process" instead of
"non-repudiation".  I was thinking more in terms of that process and the
general notion that one can never have too much documentation proving one's
point--i.e. in this case the indisputably "full" CRL-- whereas in day to
day
activities the efficiencies gained by deltas cover what undoubtedly will be
the vastly larger number of undisputed transactions.

So I was thinking that it would be unwise for us to needlessly burden 99%
(?)
of the solution space to address issues associated with the remaining 1%,
hence break out fulls from deltas.  Now, I'm not a lawyer, but that all
said, I think the assured presence of a full CRL in the case of a "dispute
resolution event" would very useful to that 1%.  One is otherwise faced
with
proving that one had fully accumulated all relevant deltas.  Thus mandate
fulls as an assured baseline regardless of the PKI context, but with
perhaps
a longer production period that nonetheless contributes evidence to a
possible discovery process.  Again, I'm not a lawyer, but I have played
with
them on the street.

Ultimately, I'm still convinced that the only effective resolution is a
dynamically produced, digitally signed assertion (i.e. OCSPv2 with its DPV
extension).  But that's an entirely different buffalo hunt.

Mike

> -----Original Message-----
> From: Tom Gindin [mailto:[email-masked]]
> Sent: Tuesday, April 24, 2001 10:43 AM
> To: Michael Myers
> Cc: David P. Kemp; [email-masked]
> Subject: RE: delta-CRLs and NR
>
>
>
>      When non-repudiation is an actual practice, doesn't the revocation
> status need to be checked as of a time no earlier than the actual
> signature
> of the non-repudiable message or document?  And won't a full CRL (or a
> delta, for that matter) rarely have been published with such an effective
> time at the time an RP initially receives such a message or document?
>      It is perfectly true that it is much easier to check a
> single full CRL
> than a CRL with deltas.  However, I don't see why the problem is more
> severe for NR except that an NR system is even less tolerant of false
> negatives on revocation than authentication is.
>
>           Tom Gindin
>

---

From: Santosh Chokhani <[email-masked]>
Date: Tue, 24 Apr 2001 15:23:42 -0400

Mike:

Your last statement in contradiction with my grasp of X.509

-----Original Message-----
From: Michael Myers [mailto:[email-masked]]
Sent: Tuesday, April 24, 2001 3:26 PM
To: Santosh Chokhani; Tom Gindin
Cc: David P. Kemp; [email-masked]
Subject: RE: delta-CRLs and NR

I understand.  But the trajectory of the dialog seemed to be suggesting
elimination the full CRL context, hence in that forward scenario one would
have no choice but to face the accumulation task.  Also, the proposal to
enable a different period of production between a full CRL and its
associated deltas (thus enabling periods of delta-only activity between full
CRL production) does suggest that there might exists cases where more than
one delta is necessary to span the gap between fulls.

Mike

-----Original Message-----
From: Santosh Chokhani [mailto:[email-masked]]
Sent: Tuesday, April 24, 2001 12:11 PM
To: Michael Myers; Tom Gindin
Cc: David P. Kemp; [email-masked]
Subject: RE: delta-CRLs and NR

Mike:
You do NOT need to accumulate all the relevant deltas.  You only need the
referenced base or later and the delta in "your hand" to create a full
revocation picture.