- From: Joseph M. Reagle Jr. <reagle@w3.org>
- Date: Fri, 27 Jul 2001 17:24:19 -0400
- To: "Dournaee, Blake" <bdournaee@rsasecurity.com>, "John Boyer" <jboyer@PureEdge.com>
- Cc: "Donald E. Eastlake 3rd" <dee3@torque.pothole.com>, w3c-ietf-xmldsig@w3.org, "Shi, Angela" <ashi@rsasecurity.com>
At 19:37 7/9/2001, Dournaee, Blake wrote:
>We have a question about the XML DSig spec regarding Section 4.3.3.2,
>Reference Processing Model.
...
>Consider the following clarification, and please let us know if this is the
>correct interpretation:
>
>"
>When a same-document reference (1) or a bare fragment identifier (2) is used
>as a URI Reference, it must be dereferenced as an XPath node-set. This
>node-set must have ALL comments stripped from it (e.g. equivalent to
>passing the node-set through an arbitrary 'comment stripping'
>transformation) before canonicalization is used. The type of
>canonicalization used is orthogonal to the stripping of all comments. For
>example, comments must still be stripped even if a canonicalization method
>that preserves comments is used.
>"
>And finally, why must comments be stripped anyway?
I too am a little foggy on the relationship of XPointer and comments here.
The appropriate text is:
http://www.w3.org/Signature/Drafts/xmldsig-core/Overview.html#sec-Same-Document
>...
>5. if the URI is not a full XPointer, then delete all comment nodes
>...
>The last step is performed for null URIs, barename XPointers and child
>sequence XPointers. To retain comments while selecting an element by an
>identifier ID, use the following full XPointer: URI='#xpointer(id('ID'))'.
>To retain comments while selecting the entire document, use the following
>full XPointer: URI='#xpointer(/)'. This XPointer contains a simple XPath
>expression that includes the root node, which the second to last step above
>replaces with all nodes of the parse tree (all descendants, plus all
>attributes, plus all namespaces nodes).
Since one has the option of deciding which c14n to use (the implicit without
comments, or an explicit with comments, or an explicit without) I no longer
remember why the XPath nodeset processing needs this final step? John?
--
Joseph Reagle Jr. http://www.w3.org/People/Reagle/
W3C Policy Analyst mailto:reagle@w3.org
IETF/W3C XML-Signature Co-Chair http://www.w3.org/Signature
W3C XML Encryption Chair http://www.w3.org/Encryption/2001/
Received on Friday, 27 July 2001 17:24:26 UTC