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Re: WG Review: Secure Telephone Identity Revisited (stir)

2013-08-21 14:36:03
I noticed in a few places the suggestion to replace telephone number with 'identity'.

I think that this is a particularly bad enhancement given how widely the term identity is understood by most people.

In RFC 6973 we defined the term (which is inline with many of the identity management efforts) as:

   $ Identity:  Any subset of an individual's attributes, including
      names, that identifies the individual within a given context.
      Individuals usually have multiple identities for use in different
      contexts.

I don't think that this is what the work is about.

Let's keep the charter text concise and enhance it later once work gets done.

Ciao
Hannes

On 08/21/2013 09:25 PM, Christopher Morrow wrote:
+ iesg
-iesg-secretary

On Wed, Aug 21, 2013 at 3:18 PM, Christopher Morrow
<morrowc(_dot_)lists(_at_)gmail(_dot_)com> wrote:
On Wed, Aug 21, 2013 at 3:07 PM, Dave Crocker <dhc(_at_)dcrocker(_dot_)net> 
wrote:
The following mostly are points that I raised within the group's mailing
list discussion, during charter development.  In my view, they have not yet
been adequately resolved:


On 8/21/2013 10:52 AM, The IESG wrote:

    Please send your comments to the IESG mailing list (iesg
at ietf.org) by 2013-08-28.

...

The STIR working group will specify Internet-based mechanisms that allow
verification of the calling party's authorization to use a particular
telephone number for an incoming call.


"use a particular telephone number for an incoming call" has no obvious and

it'd actually be kind of nice if the focus was NOT on the (us)
10-digit "number", but instead on the 'identity' making the call.
There's a real chance to move beyond the '10-digit number' and to some
stronger, wider, richer sense of 'identity'... we should take that
opportunity and run with it.

unambiguous technical meaning.  In fact, it seems to imply the meaning of
"authorization to call a particular number".  However of course that's not
the intended meaning.  Since this is the only text in this paragraph that
says what the working group will /do/ it should make its statement with
clarity and technical substance.

That is, the charter needs to use a precise term for specifying the specific
role of the number of interest.  In earlier drafts, "caller id" was used.

s/number/identity/

The next sentence uses "source telephone number".  Perhaps that is
acceptable.

no... focus on 'telephone number' is broken. Hell, it's not even
what's used in the phone system anyway... not really.

Since it has  become fairly easy
to present an incorrect source telephone number, a growing set of
problems have emerged over the last decade.  As with email, the claimed
source identity of a SIP request is not verified, permitting unauthorized


As a matter of form, I'll note the SIP's community's use of "identity" is
what is called "identifier" in the identity community.

...

As its priority mechanism work item, the working group will specify a SIP


Reference to work priority is only meaningful in the face of a list of tasks
that will be considered simultaneously and what it means to give priority to
one over another.  Based on the lengthy mailing list discussion of in-band
vs. out-of-band, it appears that the current charter is actually intended to
support simultaneous work on alternative mechanisms, rather than pursuing
them sequentially.

This should be made explicit.  If the requirement is to work on them
sequentially, then state that.  If the intent is to work on both approaches
simultaneously, then say that.

...


In addition to its priority mechanism work item, the working group will
consider a mechanism for verification of the originator during session
establishment in an environment with one or more non-SIP hops, most
likely requiring an out-of-band authorization mechanism.  However, the
in-band and the out-of-band mechanisms should share as much in common as
possible, especially the credentials.  The in-band mechanism must be sent
to the IESG for approval and publication prior to the out-of-band
mechanism.


"in-band and the out-of-band mechanisms should share as much in common as
possible"

This is the essential text that mandates working on both approaches
simultaneously and makes the earliet assertion about priority moot. (Note
how far down in the charter this is buried, yet how fundamental a
requirement is establishes.)


...

Input to working group discussions shall include:


That's a lengthy list of documents.  Why has it left out other documents
discussed during charter development and clearly of continuing interest to
the effort, namely:

    A proposal for Caller Identity in a DNS-based Entrusted Registry
    (CIDER)
    draft-kaplan-stir-cider-00

    An Identity Key-based and Effective Signature for Origin-Unknown
    Types
    draft-kaplan-stir-ikes-out-00


d/


--
Dave Crocker
Brandenburg InternetWorking
bbiw.net