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RE: Namespaces and URNs

From: Phillip M Hallam-Baker <pbaker@verisign.com>
Date: Wed, 27 Oct 1999 18:52:58 -0400
To: "Joseph M. Reagle Jr." <reagle@w3.org>, "IETF/W3C XML-DSig WG" <w3c-ietf-xmldsig@w3.org>
Cc: <timbl@w3.org>
Message-ID: <004701bf20ce$03d36280$6e07a8c0@pbaker-pc.verisign.com>
The IETF process only prohibits normative references to non normative
IETF RFCs. It does not prohibit reference to normative W3C standards.

The URN group was denied normative reference standing for good reasons
unlikely to be resolved to the satisfaction of the IESG this millenia
(14 months).

Names arrive at their meaning through usage. The problem with the URN
working group was that they pretty much ensured that their proposal would
never achieve any usage. Lack of hierarchy never did much good for
gopher URLs as I recall. I remain mystified at by the advantages of
making the URN syntax incompatible with the URL syntax.

If names are used for a purpose then they have meaning and it is
inaccurate to describe them as 'bogus'.

I note that Microsoft is already coding strings such as
URN:schema-microsoft-com: into IE5.0.

Whatever naming scheme anyone comes up with, there will be nothing
to stop someone assigning an incompatible semantics to a name. The
persistence of names is not a technical issue, it is a political
and governmental issue.

[Chances are that somewhere in the universe another planet has
chosen or will chose an 8bit character set. Given this estimate
the probability that our URN encoding will turn out to be unique,
I doubt that the improbability is of cryptological proportions.]

It seems to me that the IESG is pretty much inviting W3C to take
the URN registration policy off their hands. If the URN legacy is too
wedged we could always define a new class of URI, call it a URS
(Uniform Resource Semiote), provide a means for any party to issue their
own URS's using the IANA issued DNS infrastructure as registration

Then W3C can issue the needed character strings. If W3C can't manage
such a process there is a pretty good chance nobody else will either.


> -----Original Message-----
> From: w3c-ietf-xmldsig-request@w3.org
> [mailto:w3c-ietf-xmldsig-request@w3.org]On Behalf Of Joseph M. Reagle
> Jr.
> Sent: Wednesday, October 27, 1999 5:37 PM
> Cc: timbl@w3.org
> Subject: Namespaces and URNs
> As we all know, we are presently using URNs for algorithm identifiers that
> are non-sensical -- they do not exist; they have not been registered.
>       Assignment of a URN is a managed process.
>       I.e., not all strings that conform to URN syntax are necessarily
>       valid URNs.  A URN is assigned according to the rules of a
>       particular namespace (in terms of syntax, semantics, and process).
>       [1] ftp://ftp.isi.edu/in-notes/rfc2611.txt
> Of course, we've needed some space fillers in our draft until we come up
> with something better. To that end (something better), I've been
> looking at
> the various policies of institutions and even have a potential syntactical
> solution that might help our situation.
> In referencing W3C specifications we are ok. While verbose, the
> W3C uses the
> dated name (URL) of a specification to reference the semantics of that
> specification.
> RFC2611 [1] specifies how to register/request a URN from IANA if
> we need to
> do so (though I prefer W3C namespace in the XML context) but we can't yet
> refer to other IETF semantics using URNs. The IETF URN Working
> Group charter
> [2] lists an Informational RFC proposal [3] regarding the
> allocation of IETF
> URNs to RFCs, but there is still no governing policy to my knowledge.
> [2] http://www.ietf.org/html.charters/urn-charter.html
> [3] ftp://ftp.isi.edu/in-notes/rfc2648.txt
> And of course, this says nothing of other institutions like RSA, ISO, etc.
> When I was speaking with Tim Berners-Lee and Dan Connolly about this issue
> we agreed that "making up" URNs defeats the purpose of URNs: ensuring
> integrity, persistence, and non-collission based institutional
> management of
> that namespace. The WG needs to use registered URNs, or create our own and
> then define which references apply to which tokens in that name space.
> Dan and Tim suggested something that I think interesting if I
> understand it
> properly. We might have attributes that look like:
>       <DigestValue IETF:base64="a23bcd43">
> Or, we could try something along the lines of nesting
>  <Signature xmlns="http://www.w3.org/1999/10/signature-core">
>         xmlns:IETF="http://www.w3.org/1999/10/signature-core/IETF"
>     <SignedInfo id="a">
>           <ObjectReference Location="http://www.ietf.org">
>                    <c14n>
>                       <IETF:sha1>
>                           <IETF:base64>a23bcd43</base64>
>                       </IETF:sha1>
>                    </c14n>
>                 </ObjectReference>
> and in the spec we define what signarure-core/IETF or /NIST means via a
> normative reference.
> What would really be nice is the ability to have qualified
> attribute values!
> Like:
>        <DigestValue Algorithm="IETF:base64">a23bcd43</DigestValue>
> This feature is not in the present XML Schema WD [4].  However, the Schema
> WG Chair tells me they expect to have this in the next or following draft.
> [4] http://www.w3.org/TR/1999/WD-xmlschema-1-19990924/
> Any other thoughts? I don't know how the IESG will react, but
> I've been told
> that W3C will not  look kindly upon bogus URNs. (A further request on XML
> Schemas follows in the next message.)
> _________________________________________________________
> Joseph Reagle Jr.
> Policy Analyst           mailto:reagle@w3.org
> XML-Signature Co-Chair   http://w3.org/People/Reagle/
Received on Wednesday, 27 October 1999 18:51:39 UTC

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