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How far to Canonicalize... Re: Xpointer Coordination

From: <dee3@us.ibm.com>
Date: Mon, 19 Apr 1999 16:26:33 -0400
To: "Signed-XML Workshop" <w3c-xml-sig-ws@w3.org>
Message-ID: <85256758.0071948D.00@D51MTA10.pok.ibm.com>
XPointer also strikes me as an example of the slippery slope of
canonicalization.  If we want canonicalization to be stable, it needs to be
bounded and clear.  Saying it is limited to "XML semantics" isn't adequate.
You need to specify just what is covered.  Probably namespaces should be.
But should XPointer?  Note that there are generally lots of equivalent
forms of the same XPointer.  Should they be canonicalized to a standard
form?  In general, any XML extension designed without digital signatures in
mind will have the potential of motivating additional canonicalization


Donald E. Eastlake, 3rd
17 Skyline Drive, Hawthorne, NY 10532 USA
dee3@us.ibm.com   tel: 1-914-784-7913, fax: 1-914-784-3833

home: 65 Shindegan Hill Road, RR#1, Carmel, NY 10512 USA
dee3@torque.pothole.com   tel: 1-914-276-2668

"Joseph M. Reagle Jr." <reagle@MIT.EDU> on 04/14/99 12:33:28 PM

To:   "Signed-XML Workshop" <w3c-xml-sig-ws@w3.org>
cc:    (bcc: Donald Eastlake/Hawthorne/IBM)
Subject:  Xpointer Coordination

[Sorry, that message escaped my Pilot before I got to include the

There are two areas where Xpointer may be relevant to signed-XML (so keep
your eye on [1]):

1. application: the use of a hash on an XML document to have an assurance
that the content referenced by an Xpointer has not been changed since the
pointer was created.
2. dependency: the use of the more advanced locators could be used to
provide for the scoping/filtering operations of some signed-XML
applications. [2] (I'm not sure how much of that functionality should be
part of signed-XML anyway.)

[1] http://www.w3.org/TR/WD-xptr
[2] http://www.w3.org/TR/WD-xptr#3.7.1
Regards,          http://web.mit.edu/reagle/www/
Joseph Reagle     E0 D5 B2 05 B6 12 DA 65  BE 4D E3 C1 6A 66 25 4E
independent research account
Received on Monday, 19 April 1999 16:40:51 UTC

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