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Re: XML Signature use of Canonical XML

From: Martin J. Duerst <duerst@w3.org>
Date: Tue, 11 Apr 2000 12:52:57 +0900
Message-Id: <4.2.0.58.J.20000411124731.009cbc50@sh.w3.mag.keio.ac.jp>
To: Dan Connolly <connolly@w3.org>
Cc: Ed Simon <ed.simon@entrust.com>, "'w3c-xml-core-wg@w3.org'" <w3c-xml-core-wg@w3.org>, "'w3c-ietf-xmldsig@w3.org'" <w3c-ietf-xmldsig@w3.org>
At 00/04/08 08:38 -0500, Dan Connolly wrote:

It suddenly appeared to me under the shower this morning
that there is a serious problem:


>On the other hand, it is clear how to tell producers
>of XML documents to declare their namespaces in
>a normalized way; if somebody told me, the guy
>who knows the semantics of my stylesheet document,
>that it has to be in normal form, I can rewrite
>the XPath expressions and such:
>
><n1:stylesheet
>     xmlns:n1      ="http://www.w3.org/1999/XSL/Transform" version="1.0">
><n1:template
>     xmlns:n1      ="http://www.w3.org/1999/XSL/Transform"
>     xmlns:n2    ="http://www.w3.org/1999/xhtml"
>
>  match="n2:table//n2:tr/n2:td[string-length(normalize-space(.))&gt;1]">
>...
></n1:stylesheet>

Unfortunotaly, the above is not in namespace-normal form
as defined by the current c14n draft. n2 is on no attribute
and no element, and thus by the definition of c14n just
superfluous and not allowed to be there.

And you may think about ways to fix this, but it's not possible
to fix this easily, unless you want to give up any chance to
veryfy namespace-normal automatically.


>So specifying a way to *test* whether an XML document's namespace
>declarations are in normal form is straightforward,


Unfortutately, it isn't.


Regards,  Martin.
Received on Tuesday, 11 April 2000 01:32:45 GMT

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