Subject: What is the PKIX TSP anyway?

From: "todd glassey" <[email-masked]>
Date: Tue, 12 Feb 2002 22:09:43 -0800

I wrote this about two weeks ago and wound up striking half of it as being
too obnoxious to post. But the other part I think is important to the bigger
picture of timestamps and timestamping as an evidentiary practice especially
when compared to XML based receipts.

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Folks - I want to point out that I am not in favor of trashing(1) all the
effort that has gone into the PKIX TSP effort but I want to steer it towards
a more usable service model and one that will adapt to new Token-Types and
Verification or Assurance Models.

Rethinking the TSP and TST models
-------------------------------------
To do this some major rethinking of the uses of the tokens is going to need
to be done and to that end I would propose that this WG collectively tell
its management that the current TSP provides no more realizable assurance
for any processes that might use it than a clear text distributed processing
model does and that makes there no reason to use this system since it is
totally predicated on the security and operational model of the Audit on the
platform below the TSA in order to reinforce its own veracity.

The reasons for this failing are the stated uses for the TST's themselves.
And that the TSP does not take into account the facility issues a "proofing
model" would require to demonstrate its own integrity. I

TSP vs. NTP
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Another issue is that the service levels provided by the TSP and the TSA,
i.e. the functions they perform and what they actually provide to the
applications or users depending on them, have now degraded such that they
are no more potent than a marque that could be made with NTP. The problem
here again is that NTP predates the TSP by years and has tens of thousands
of implementations at minimum in the world today. What this really meant is
that the use of NTP for timestamping requires a practice statement, and not
a protocol and that is what choked PKIX on the process of using one of the
IETF's other protocols for its TS Protocol.

The bottom line on the TSP is that PKIX refuses to acknowledge that now more
than ever - the TSP they wound up with is a neutered knock-off of NTP and
that NTP has a better TS Token generation capability since it addresses the
credibility of the Time Data in the TST.  What this means is that most all
the functions that the TSP can perform now and many that it cant are already
in place inside the NTP protocol and what is missing from both protocol is
the simple token verifier application.

TSA's and TSP's are needed
------------------------------
As to a TSP - let me restate for the third time here - that they are
critical, but for Evidentiary Purposes, not as a part of simple
decision-support processes. No one in their right mind is going to need a
TSToken to stick into a database on a secured system to indicate some
digital event. The would just create a set of even-type markers and throw
one of them into the DB with the time the event happened. VIOLA - Time
stamp!
The Securing of the system provides credibility of the document's induction
time into the DB, likewise the reports generated by the IDS tools and System
Integrity tools also fold in to reinforce the methodology of doing
timestamps exactly how they are done today.

Yesterday's vs. Today's TST's
-------------------------------
Timestamps today are fields in DB based applications and whether there is a
hash of the document included or not, the model where a TTP is already in
place where needed, and is accomplished through simple DB Replication from
site to back-up site.  That means that the total need to date for TS's is
that of those reproduced in the form of reports from DB based applications.
So what in the commercial world would require the addition of this PKIX TS
Token Structure as its evidentiary marque? Why not just use a Server that
has a document reception application written on it and a report generator
that used Syslog and NTP to timestamp the receipt of each document. I can
use the SHAsign and MD5hash tools to build the signature and boom there we
go.

If PKIX is going to create a better token and TS Process, that at minimum
what PKIX needs to do is to hone the calling and verification API's to this
TSP to generate standard calling and response sequences that are more in
tune with the "validity of the Token and its Payload(s)", and likewise
generate a standard set of token structures to represent a slew of
commercial type events, maybe even use portions of what the
ONLINE-TRADING-PROTOCOL WG built up as the transaction types.

The problem is that there is no commercial way to use this technology, and
while Italy may indeed have legal requirements for the use of Time Stamps,
they will soon find out that what they were really looking for is a process
for automating Notorial Ceremonies.

Todd