Re: [Rats] Use case -> architecture document

Carsten Bormann <cabo@tzi.org> Thu, 10 October 2019 11:45 UTC

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From: Carsten Bormann <cabo@tzi.org>
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Date: Thu, 10 Oct 2019 13:45:48 +0200
Cc: Juergen Schoenwaelder <J.Schoenwaelder@jacobs-university.de>, Henk Birkholz <henk.birkholz@sit.fraunhofer.de>, "Xialiang (Frank, Network Standard & Patent Dept)" <frank.xialiang@huawei.com>, "rats@ietf.org" <rats@ietf.org>
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To: Kathleen Moriarty <kathleen.moriarty.ietf@gmail.com>
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Subject: Re: [Rats] Use case -> architecture document
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Hi Kathleen,

It is hard to keep up with this torrent, and I’ll respond to a snapshot.

However, I would like to point out that there is a place for specs, and a place for books.
When 6LoWPAN was done (RFC 4919, RFC 4944), we wrote a book, and that is definitely a better place to get a thorough introduction.

The job of the spec is to crystallize consensus, not to serve as a textbook.
Where editorial issues hinder understanding, this can (and should!) be fixed in the WG process.
Restarting the effort comes with the danger of diluting the hard-earned consensus.

I like the fact that the spec is 10 pages net now.  Adding examples and other material may hinder adoption by making people think that the architecture is complex.  It is not.  (I made this mistake enough already, no need to repeat it here.)

The main point of the architecture is to define the roles in unambiguous terms, and the axioms we have about these roles.  Without this, we cannot communicate.  If you try buying a house and don’t understand the roles of buyer, seller, bank, and notary, you won’t get a good outcome.  The architecture document provides this, and adding introductory material is only going to help so much (i.e., please do, but in moderation).

So my recommendation would be to adopt this document quickly, and to fix any impediments to understanding it.
Let the flowers bloom and write great documents about use cases (done), usage scenarios and workflow patterns.  These can then also make use of the agreed terminology, which will tremendously help in understanding them as a group.
But please don’t hold up the progress of the architecture document by introducing non-essential surgery.  We need this document, shipped.

Grüße, Carsten


> On Oct 9, 2019, at 18:03, Kathleen Moriarty <kathleen.moriarty.ietf@gmail.com> wrote:
> 
> 
> I would rather see the architectural patterns come before the specific terminology.  If you look through the slides from Dave's presentation at our previous interim meeting, he laid out several architectural patterns using the same language that is used in SUIT and TEEP.  It is desirable, IMO, to begin with architectural patterns that can be used in necessary use cases.  Additional architectural patterns may arise, but we have a nice starting point.
> 
> See: https://datatracker.ietf.org/meeting/interim-2019-rats-02/materials/slides-interim-2019-rats-02-sessa-teep-and-rats-alignment
> It defines the passport, background check, and verifying relying party architectural patterns for RATS.  
> It also provides an illustration of how the OTrP model for device state can fold into each of those 3 RATS architectural patterns.
> 
> What Dave is planning to do is to write text describing these architectural patterns.  It will likely be in the language similar to what's been used in SUIT and TEEP as his slides match the terminology.  
> 
> Attestation has countless use cases, and several known architectural patterns to date.  The document would first define these patterns.  Then, like SUIT, a high-level description of use cases could be included with pointers to other future WG drafts that more fully define the use cases.  Any additional terminology that is necessary could then be added, but keeping in mind that we do not want unnecessary terms.  If we start from the models, it will be easier to maintain the scope and set of terms.  The terms would come from the current document, but language may be adjusted as needed.
> 
> The specific use case details that map claims could be in a later section with the IANA section defining claims for use cases to be added to the CWT and JWT registry.
> 
> I work for Dell and would like to be able to bring this work forward for PoCs.  However, our teams (like many others) use pair programming.  This means the 2 coders work as a team and in our model, they rotate to a new project every 2 weeks.  This helps with innovation and other benefits.  If each pairing team has a significant learning curve, a lot of time will be wasted and the PoC would not make progress.  
> 
> If the goal for service providers and others is to use this technology (as is my goal), we need to make it something that is accessible to many.  The developers at many organizations will use crypto libraries, but will not necessarily be security people.  They will be starting from a point where they do not have security specific language nor this very specific set of terms that is being defined.  The simpler we can keep it, the better to gain wider adoption.
> 
> I think if we step back and see what Dave does with the document to define the architectural patterns, then we can decide how we merge content with readability as a goal.
> 
> Best regards,
> Kathleen
> 
> On Wed, Oct 9, 2019 at 10:50 AM Schönwälder, Jürgen <J.Schoenwaelder@jacobs-university.de> wrote:
> Hi,
> 
> I did also look at the use cases document (I think -04) after going
> through the architecture document and I must admit that I did not find
> it too helpful to understand things better. I did not see anything
> architectural in there either. I guess I will read the teep
> architecture next and perhaps that helps me to get a better clue.
> 
> For people like me who are not deep into this technology yet, getting
> used to the rather specific terminology and concepts is a certainly a
> learning effort and I think the architecture document was on its way
> to get terms well defined and sorted out. Some more examples or
> explanations may help the reader further and I believe this can be
> achieved.
> 
> /js
> 
> On Wed, Oct 09, 2019 at 01:55:57PM +0200, Henk Birkholz wrote:
> > Hi Kathleen,
> > hi list,
> > 
> > it would help everybody, if you could explicitly highlight what the exact
> > issues wrt readability in the current architecture I-D are - always in
> > comparison with the use-case I-D, if it is doing a better job in that part?
> > 
> > Jürgen provided a good example of what he found confusing as a first time
> > reader - and that was really helpful and is resulting in ongoing work.
> > 
> > Please mind, not everything is fleshed out in the architecture (e.g. the
> > workflows derived from the use-cases). The plan was to aim for a stable
> > nucleus, address the issues raised by the list, go through adoption, and
> > finish the document via the issue tracker in a structured process.
> > 
> > In summary, without an actual understanding why you (or others!) think the
> > document is still hard to read, there is no way of compare readability later
> > on also. It would be really good to get more precise feedback on that.
> > 
> > Viele Grüße,
> > 
> > Henk
> > 
> > 
> > 
> > 
> > On 09.10.19 13:31, Kathleen Moriarty wrote:
> > > Hi Frank,
> > > 
> > > Thank you for voicing your concern.  I think some may hold off until the
> > > updates are provided, but please do voice your opinions.  I agree that
> > > this work is too important and as such, readability is a high priority.
> > > If you read through the TEEP and SUIT architecture drafts, they are
> > > quite easy to follow and understand.  That is critical for wide spread
> > > adoption.  We may be able to find a balance, but I think this exercise
> > > may speed progress as we have not decided to adopt this draft yet as a
> > > working group item.
> > > 
> > > As it stands, the use case document is not an architecture document, but
> > > it could be shaped as such and I'd really like to see if we can do that
> > > in short order to have a comparison prior to an adoption call.
> > > 
> > > Best regards,
> > > Kathleen
> > > 
> > > On Wed, Oct 9, 2019 at 6:53 AM Xialiang (Frank, Network Standard &
> > > Patent Dept) <frank.xialiang@huawei.com
> > > <mailto:frank.xialiang@huawei.com>> wrote:
> > > 
> > >     Hi Kathleen,____
> > > 
> > >     __ __
> > > 
> > >     I am very concerned with this new direction and I strongly object.____
> > > 
> > >     __ __
> > > 
> > >     Current architecture draft goes through a lot discussions and
> > >     reaches many consensus. Right now, it really helps IETF (Teep for
> > >     example), FIDO, TCG and many others. The only issues are on
> > >     readability, the standards track and the completeness (e.g.,
> > >     passport and background check are still missing). It is an very good
> > >     document and correct terminology is very important for remote
> > >     attestation.____
> > > 
> > >     __ __
> > > 
> > >     About use cases document, Its goal is just to clarify a sample list
> > >     of scenarios that remote attestation can apply to and then deduce
> > >     the requirements and the following concrete protocol drafts. It is
> > >     not fit to be an architecture.____
> > > 
> > >     __ __
> > > 
> > >     The current architecture is too important for telecom and network
> > >     equipment vendors and service providers. I have strong doubts that
> > >     current EAT and OTrPv2 alone is suitable for the (virtualized)
> > >     network infrastructure situation.____
> > > 
> > >     __ __
> > > 
> > >     B.R.____
> > > 
> > >     Frank____
> > > 
> > >     ____
> > > 
> > >     __ __
> > > 
> > >     This e-mail and its attachments contain confidential information
> > >     from HUAWEI, which is intended only for the person or entity whose
> > >     address is listed above. Any use of the information contained herein
> > >     in any way (including, but not limited to, total or partial
> > >     disclosure, reproduction, or dissemination) by persons other than
> > >     the intended recipient(s) is prohibited. If you receive this e-mail
> > >     in error, please notify the sender by phone or email immediately and
> > >     delete it!____
> > > 
> > >     __ __
> > > 
> > >     *发件人:*RATS [mailto:rats-bounces@ietf.org
> > >     <mailto:rats-bounces@ietf.org>] *代表 *Kathleen Moriarty
> > >     *发送时间:*2019年10月8日19:25
> > >     *收件人:*rats@ietf.org <mailto:rats@ietf.org>
> > >     *主题:*[Rats] Use case -> architecture document____
> > > 
> > >     __ __
> > > 
> > >     Hello!
> > > 
> > >     I read through the latest version of the ‘use case’ document
> > >     yesterday and found it very easy to read and understand, meaning I
> > >     think it is written well and could be easily understood by many
> > >     without having to climb up a learning curve. ____
> > > 
> > >     __ __
> > > 
> > >     First, this could be a very useful document to register claims for
> > >     the use cases.
> > > 
> > >     Second, if the workflow for the passport and background check were
> > >     added and put in terms of the open trust protocol v2 from TEEP, we
> > >     have a fairly nice architecture document that’s easy to read and may
> > >     gain adoption.  The workflows cover the various interactions between
> > >     roles and TEEP has actively broken up OTrP in v2 to
> > >     accommodate using EAT tokens, this would help create that link and
> > >     make it very clear.
> > > 
> > >     The other thing I like about the use case document and think we
> > >     should expand on is the references to other work items.  This makes
> > >     it an architecture document that maps out the full plan of the WG.
> > > One like that was extremely well received by all the ADs that don’t
> > >     like informational/helpful documents.
> > > 
> > >     I’m a bit nervous with the terminology being defined and would love
> > >     to see something like this that’s simplified and more easily
> > >     adoptable. ____
> > > 
> > >     __ __
> > > 
> > >     I appreciate the work done to improve the architecture document, but
> > >     I do think the structure changes to the use case document as
> > >     suggested could result in an easier to understand (and therefore
> > >     easier to adopt) document.____
> > > 
> > >     __ __
> > > 
> > >     While the architecture document is more readable, I think we can do
> > >     better.  Adoption is important and our timeliness matters a lot for
> > >     this work.  EATs can be used for may use cases with OTrPv2, so let's
> > >     keep it as simple as we can.
> > > 
> > >     Thoughts are appreciated.
> > > 
> > >     Best regards,
> > >     Kathleen-- ____
> > > 
> > >     __ __
> > > 
> > >     Best regards,____
> > > 
> > >     Kathleen____
> > > 
> > > 
> > > 
> > > -- 
> > > 
> > > Best regards,
> > > Kathleen
> > > 
> > > _______________________________________________
> > > RATS mailing list
> > > RATS@ietf.org
> > > https://www.ietf.org/mailman/listinfo/rats
> > > 
> > 
> > _______________________________________________
> > RATS mailing list
> > RATS@ietf.org
> > https://www.ietf.org/mailman/listinfo/rats
> 
> -- 
> Juergen Schoenwaelder           Jacobs University Bremen gGmbH
> Phone: +49 421 200 3587         Campus Ring 1 | 28759 Bremen | Germany
> Fax:   +49 421 200 3103         <https://www.jacobs-university.de/>
> 
> 
> -- 
> 
> Best regards,
> Kathleen