RFC 3076 (rfc3076) - Page 2 of 28

Canonical XML Version 1

RFC 3076                     Canonical XML                    March 2001


Table of Contents

   1. Introduction...............................................  2
   1.1 Terminology...............................................  3
   1.2 Applications..............................................  4
   1.3 Limitations...............................................  4
   2. XML Canonicalization.......................................  6
   2.1 Data Model................................................  6
   2.2 Document Order............................................ 10
   2.3 Processing Model.......................................... 10
   2.4 Document Subsets.......................................... 13
   3. Examples of XML Canonicalization........................... 14
   3.1 PIs, Comments, and Outside of Document Element............ 14
   3.2 Whitespace in Document Content............................ 15
   3.3 Start and End Tags........................................ 16
   3.4 Character Modifications and Character References.......... 17
   3.5 Entity References......................................... 19
   3.6 UTF-8 Encoding............................................ 19
   3.7 Document Subsets.......................................... 20
   4. Resolutions................................................ 21
   4.1 No XML Declaration........................................ 21
   4.2 No Character Model Normalization.......................... 21
   4.3 Handling of Whitespace Outside Document Element........... 22
   4.4 No Namespace Prefix Rewriting............................. 22
   4.5 Order of Namespace Declarations and Attributes............ 23
   4.6 Superfluous Namespace Declarations........................ 23
   4.7 Propagation of Default Namespace Declaration in Document
       Subsets................................................... 24
   4.8 Sorting Attributes by Namespace URI....................... 24
   Security Considerations....................................... 24
   References.................................................... 25
   Author's Address.............................................. 26
   Acknowledgements.............................................. 27
   Full Copyright Statement...................................... 28

1. Introduction

   The XML 1.0 Recommendation [XML] specifies the syntax of a class of
   resources called XML documents.  The Namespaces in XML Recommendation
   [Names] specifies additional syntax and semantics for XML documents.
   It is possible for XML documents which are equivalent for the
   purposes of many applications to differ in physical representation.
   For example, they may differ in their entity structure, attribute
   ordering, and character encoding.  It is the goal of this
   specification to establish a method for determining whether two
   documents are identical, or whether an application has not changed a
   document, except for transformations permitted by XML 1.0 and
   Namespaces.



Boyer                        Informational