Re: [wss] Proposed text on C14N

[merlin <merlin@baltimore.ie>]

r/rsalz@datapower.com/2003.08.28/23:54:44
>> If the application cares about the tag, then the
>> original message should have contained
>>
>>       <i:innermost xmlns:i="foo.com" ID="foo">foo</i:innermost>
>
>This would require applications to rewrite their documents so that
>any possible subset that someone might ever want to sign has all the
>necessary namespace declarations.  That imposes an impossible
>burden on anyone creating an XML document, and on anyone signing
>any XML content.

With respect to the above example, placing the namespace
declaration here or in an ancestor will make no difference;
the namespace is visibly utilized, so both inclusive and
exclusive c14n will emit it.

However, consider the following XPath transform:

  <dsig:XPath xmlns:foo="urn:foo">
    not (ancestor-or-self::foo:NotToBeSigned)
  </dsig:XPath>

Here, the foo prefix is utilized by raw text element
content; even schema awareness cannot tell that foo is used.
Exclusive c14n must be explicitly parameterized with foo or
else a signature that includes this XPath transform will fail.

The fact that this namespace declaration occurs within the
signed data is of no consequence to exclusive c14n; it only
emits parameterized or visibly-utilized namespaces.

merlin


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