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Re: Prefix rewriting considerations

From: Meiko Jensen <Meiko.Jensen@rub.de>
Date: 13 Apr 2010 21:15:24 +0200
Message-ID: <4BC4C2CC.1040007@rub.de>
To: "Pratik Datta" <pratik.datta@oracle.com>
Cc: "Scott Cantor" <cantor.2@osu.edu>, public-xmlsec@w3.org
Don't you get such qname problems as well with rewriting prefixes to
"ns$i" or to base64(hash(ns-uri))? I mean, this is about
canonicalization, hence direct input to digest computation. If you'd do
a prefix rewrite in *any* way, such references to "xsd:string" will be
broken in the c14n'ed XML.

Regarding attributes: you'll only need prefixes if an attribute is from
a different namespace than its element (rare case). Then you can define
an arbitrary prefix (e.g. using the "ns$i" approach) at that element,
which thus is only relevant for that single attribute(s) at this
particular element. Advantage is that you don't have to deal with issues
of identical prefixes mapping to different namespace uris.

best regards


Pratik Datta schrieb:
> Besides attributes, you also need to worry about QNames in content
> e.g. if you have xsi:type="xsd:string"   what will you do with the xsd prefix ?
> Pratik
> -----Original Message-----
> From: Scott Cantor [mailto:cantor.2@osu.edu] 
> Sent: Tuesday, April 13, 2010 11:50 AM
> To: Meiko Jensen; public-xmlsec@w3.org
> Subject: RE: Prefix rewriting considerations
>> continuing with today's discussion on prefix rewriting I wanted to bring
>> up the prefix-free canonicalization we published last year (ACM SWS
>> 2009). The approach basically consists in rewriting every XML element to
>> a representation like this: <localname xmlns="namespace-uri"> This way,
>> you don't need prefixes at all (besides for the attributes),
> Isn't that a major caveat? If you still have to deal with them for
> attributes anyway, what's the advantage?
> -- Scott
Received on Tuesday, 13 April 2010 19:15:44 UTC

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