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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!

Rob Lugt
ElCel Technology
Received on Tuesday, 27 March 2001 11:05:12 UTC

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