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Character Encoding Question

From: John Boyer <jboyer@PureEdge.com>
Date: Tue, 28 Nov 2000 14:39:27 -0800
To: "Martin J. Duerst" <duerst@w3.org>, <w3c-ietf-xmldsig@w3.org>
Message-ID: <BFEDKCINEPLBDLODCODKAEKLCGAA.jboyer@PureEdge.com>
Hi Martin and group,

I received a letter today from Jeff Cochran (JCochran@docutouch.com)
regarding a tweak that would appear to be needed regarding c14n and xml
signature.

The I18N group asked us to include a sentence along the lines of "REQUIRED
to use Normalization Form C [NFC] when converting an XML document to the UCS
character domain from a non-Unicode encoding".

Apparently this is not exactly what is meant since UCS-4 character planes
outside of the BMP are technically non-Unicode.  The point Jeff makes is
that he doesn't know whether to apply NFC to UCS data that appears outside
of the BMP.

Question:  Should the statement be rewritten?  If so, how?

Thanks,
John Boyer
Team Leader, Software Development
Distributed Processing and XML
PureEdge Solutions Inc.
Creating Binding E-Commerce
v: 250-479-8334, ext. 143  f: 250-479-3772
1-888-517-2675   http://www.PureEdge.com <http://www.pureedge.com/>



-----Original Message-----
From: w3c-ietf-xmldsig-request@w3.org
[mailto:w3c-ietf-xmldsig-request@w3.org]On Behalf Of Martin J. Duerst
Sent: Friday, November 24, 2000 6:17 PM
To: w3c-ietf-xmldsig@w3.org
Cc: lilley@w3.org
Subject: Fwd: I18N problem in XML canonicalisation


Chris Lilley just pointed out the following problem
in C14N. I think this at least has to be explained
much more clearly in the notes.

>http://www.w3.org/TR/xml-c14n#Example-UTF8
>
>Demonstrates using *two* NCRs foa single UTF-8 character (because it uses
>two bytes in UTF8 !!!

It's not really NCRs. It's a special notation to stand in for byte values.


>I suspect you may have a problem with that..... given that even surrogates
>use a single NCR not two. Also, its not clear the result is even
>wellformed!

There needs to be a much better note to make very clear that (different
to the other examples), this example is not really intended to be XML
and cannot be used directly in a test. It would also be advisable
to provide an actual file that contains the real bytes, or to point
to it if that's already around.

Regards,    Martin.
Received on Tuesday, 28 November 2000 17:39:39 GMT

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