Subject: Re: My objections to the submitted draft

From: Peter Sylvester <[email-masked]>
Date: Mon, 2 Feb 2004 13:10:26 +0100 (MET)

> 
> I believe that the goal of LTANS is to archive evidence, possibly along 
> with the document, that proves that the document existed at a certain 
> time in the past.  This goal was also illustrated by Aleksej in his last 
> post.  Although document format and its transition is important, I do 
> not believe that is the goal of LTANS.
> 
The equivalent of scanned copies of paper is the electronic
version just before printing, archiving this, i.e. even a pdf 
form may be useful for an intermediate time and
sufficient for some applications, but it does not make
sense in the long term since the form or layout of a 
document is a security feature and not important for
the information, e.g. a propietary act signed and sealed on
particular support/paper.  

I see the following as some extreme points of some space
may be multidimensional.

- creating an assertion that something has been archived
  and will be safe for a defined time without looking 
  at the actual content. Such data cannot be transformed
  since they are only a representation of a possible
  unknown structure (including the possibility the the
  representation is the result of data encipherment).

- creating an assertion that something conformant to a certain
  structure and/or law etc has been validated and archived.
  such structures which are representations of some information
  can be transformed to another representation. 

As soon as the assertion is created the process is divided into
two parts (at least):

- - for how much time does the assertion remain reliably
    verifyable without the need of some third party ONLINE.
   (lifetime of a digital signature)
  - can one enhance the lifetime, for example by elimination
    of keys by public hash chains
  - the need to some service for the previous and/or
    for validation after a very long time

  - The operation of a service providing the attestations
    for the three cases above

- - how does a service organise itself to be auditable, secure
    etc, etc. i.e. what internal and external mechanisms are
    used to ensure the medium and long term stability. The
    concrete operation is not our scope, but providing
    some external visibility through attestations from others
    is.
  - document formats is out of our scope to the same extend as
    it is for XML-DSIG. For notary operations and for the
    possibility of tranformation some general structuring 
    approach seems at least useful though, i.e. treating
    the layer of abstract information vs representation.

Peter

---

From: Brian Hunter <[email-masked]>
Date: Mon, 02 Feb 2004 13:58:12 +0100

Peter,

Peter Sylvester wrote:
...
>   representation is the result of data encipherment).

I believe this assertion would be represented through the archive 
policy, which the service provider or a local regulatory body defines.

>   can be transformed to another representation. 

Again I think this is a policy defined issue.  The transformations may 
be defined locally, or a standard could be defined for a general file 
format, e.g. base case could be a plain text file.

>     for the three cases above

Agree, and these points would be defined in the archive policy.

>     some external visibility through attestations from others

I think this would be a matter of local law, and not something that 
could be standardised.  Every country will likely define its own 
definition of stability and require its own service provider 
accreditation.  I believe this is similar to how each EU country defines 
its own version of accredited CAs, a regulatory body defines it, and not 
a standards body.

>     the layer of abstract information vs representation.

I'm not sure I understand your point.  As per LTANS, opaque data is to 
be archived.  This opaque data could be an CMS object that contains a 
specific type of data, which has standardised forms, or transformations. 
  But again, this structure and its transformations are irrelevant for 
the archive provider.

Brian

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From: Jeff Williams <[email-masked]>
Date: Mon, 02 Feb 2004 17:38:23 -0800

Brian and all,

  Thank you Brian for in part getting to the hart of the situation here.
I agree with almost all of your comments/remarks/observations
below.

 I still think that perhaps we should still get to the what is considered
a trusted archive, how that is specifically as possible, defined, and what
electronically signed CA's for those documents should or must be as
well as how to determine their life of validity, before needing to be
resigned,
if at all...

Note: [ I hope I stated this right and/or clearly ] If not or clarification
is needed I shall try to restate same in a different and hopefully more
clear manner...

>   But again, this structure and its transformations are irrelevant for

Regards,
--
Jeffrey A. Williams
Spokesman for INEGroup LLA. - (Over 134k members/stakeholders strong!)
"Be precise in the use of words and expect precision from others" -
    Pierre Abelard

"If the probability be called P; the injury, L; and the burden, B;
liability depends upon whether B is less than L multiplied by
P: i.e., whether B is less than PL."
United States v. Carroll Towing  (159 F.2d 169 [2d Cir. 1947]
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---

From: Brian Hunter <[email-masked]>
Date: Tue, 03 Feb 2004 17:10:16 +0100

Jeff,

> well as how to determine their life of validity, before needing to be

I agree that details of what a trusted archive is or must do, are 
important.  If you have specific suggestions as to requirements, please 
post them.

The data structure draft will specify that document evidence must be 
renewed before the expiration of the time-stamping certificate.  Another 
criterion could be based on an algorithm strength report, released by 
local regulation bodies.  That is, if the report states that a used 
algorithm will shortly be considered as weak, then a renewal is required.

Brian