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Comments on the latest C14n draft

From: Joseph M. Reagle Jr. <reagle@w3.org>
Date: Mon, 26 Jul 1999 15:38:19 -0400
Message-Id: <>
To: www-xml-canonicalization-comments@w3.org, "Tim Bray" <tbray@textuality.com>
Cc: maruyama@jp.ibm.com
Some early comments in from Hiroshi -- who was involved in the context
independent conversation and obviously a W3C member. 

Forwarded Text ----
 From: "Hiroshi Maruyama" <MARUYAMA@jp.ibm.com>
 To: w3c-ietf-xmldsig@w3.org
 Date: Fri, 23 Jul 1999 06:17:58 +0900
 Subject: Comments on the latest C14n draft
 Joseph asked for comments on the latest C14N draft.  Here are my comments.
 1. There is an extra #xA (newline) in the definition of 'canonXML'.
 We may need to be clear if we will include this newline character
 in the hash calculation or not.  See the proposed C14N syntax below.
 [1]  canonXML ::=  element #xA
 [2]  element ::=  Stag (Datachar | element)* Etag
 [3]  Stag ::=  '<' Name NSDecl? (Att NSDecl?)* '>'
 [4]  Etag ::=  '</' Name '>'
 [5]  NSDecl ::=  #x20 'xmlns:' Prefix '=' '"' Attvalchar* '"'
 [6]  Att ::=  #x20 Name '=' '"' Attvalchar* '"'
 [7]  Datachar ::=  '&amp;' | '&lt;' | '&gt;' | '&#xD;'
      | (Char - ('&' | '<' | '>' | #xD ))
 [8]  Attvalchar ::=  '&amp;' | '&lt;' | '&quot;' | '&#x9;' | '&#xA;' |
      | (Char - ('&' | '<' | '"' | #x9 | #xA | #xD))
 [9]  Name ::=  (Prefix ':')? NCName
 [10]  Prefix ::=  'n' [1-9] [0-9]*
 Having an extra newline should pose no problem if everybody follows
 the specification exactly.  However, some may wonder 'element' (line [2]
 above)  is more natural as a canonical form of an element in an XML 
 2. C14N does not include PIs.  Is this ok for our purposes?  If PI has no
 semantic information that affects the contents, it should be ok.  I tend to
 agree with this PI omission but I think it should be clearly stated in
 our dsig document that PI will not be part of authenticated information.
 3. The namespace handling is ok for the purpose of context independence.
 Any (sub)element has exactly the same canonical form regardless the
 surrounding  context.  However, the current proposal requires declaring a 
 separate namespace  for every attribute (even though the same namespace 
 is used repeatedly in the same start tag).  The resulted canonical form
 be lengthy if we have a large number of attributes.  This is again not a
big issue.
 Hiroshi Maruyama
 Manager, Network Applications, Tokyo Research Laboratory
 +81-462-73-4576, maruyama@jp.ibm.com
 Also Associate Professor, Dept. of Computer Science, Tokyo Institute of
 +81-3-5734-3953, maruyama@cs.titech.ac.jp
End Forwarded Text ----
Joseph Reagle Jr.   
Policy Analyst           mailto:reagle@w3.org
XML-Signature Co-Chair   http://w3.org/People/Reagle/
Received on Monday, 26 July 1999 15:39:37 GMT

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