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Re: Question to C14N Implementors abou Validation

From: Rob Lugt <roblugt@elcel.com>
Date: Tue, 27 Mar 2001 17:05:31 +0100
Message-ID: <022601c0b6d7$bf8b3890$0400a8c0@scott>
To: "Christian Geuer-Pollmann" <geuer-pollmann@nue.et-inf.uni-siegen.de>, "IETF/W3C XML-DSig WG" <w3c-ietf-xmldsig@w3.org>
Christian Geuer-Pollmann wrote:

> Dear C14N implementors,
>
> how did you all solve the 'problem', that [1] (Section 2.1 Data Model)
> specifies:
>
>  " ... input need not be validated. However, the attribute value
> normalization and entity reference resolution MUST be performed in
> accordance with the behaviors of a validating XML processor."
>
> The test cases from the Canonical XML spec do not validate (like the spec
> allows). Nevertheless, ID attributes have to be identified etc. Did you
> implemented your own DTD handler?

I think the issue here is not so much whether you are using a validating XML
processor, but whether or not the XML processor reads external entities.
Even non-validating processors are required to normalize attributes declared
in the internal DTD subset.  They may, but need not, do the same for
attributes declared in the external subset.

XML 1.0 [1] 5.1 states:  Non-validating processors are required to check
only the document entity, including the entire internal DTD subset, for
well-formedness /.../ they must use the information in these declarations to
normalize attribute values /.../

You may find that your XML processor allows you to disable validating but
still process external entities.  If not, try another parser!

Regards
Rob Lugt
ElCel Technology
http://www.elcel.com
Received on Tuesday, 27 March 2001 11:05:12 GMT

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