World Wide Web Consortium Issues Canonical XML as a W3C Recommendation

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New XML specification provides foundation for digital signatures -- 19 March 2001 -- The World Wide Web Consortium (W3C) today announced the release of Canonical XML 1.0 as a W3C Recommendation. This specification defines a method for serializing XML documents such that it eliminates incidental variances in their syntax as permitted by XML 1.0. This functionality is necessary to XML Signatures which requires documents to be consistently serialized for digital signature processing, so that these incidental variances do not invalidate the signature. A W3C Recommendation indicates that a specification is stable, contributes to Web interoperability, and has been reviewed by the W3C Membership, who are in favor of supporting its adoption by academic, industry, and research communities.

Canonical XML Makes XML Digital Signatures Work

Digital signatures provide integrity, signature assurance and non-repudiatability over Web data. Such features are especially important for documents that represent commitments such as contracts, price lists, and manifests. XML Signatures have the potential to provide reliable XML-based signature technology. However, various processors may introduce incidental changes into a document over the course of its processing. Canonical XML 1.0 provides a method of serializing an XML document into its canonical form. If two documents have the same canonical form, then the two documents are logically equivalent within the context of this specification. This relationship combined with XML Signature is critical for electronic commerce because it ensures the integrity of documents and protocol messages that travel between multiple XML processors.

Canonical XML Strengthens the XML Family of Technologies

Canonical XML adds another critical piece to the Extensible Markup Language (XML) family of technologies under development at W3C, which began with the XML 1.0 Recommendation, and includes Namespaces in XML, Extensible Stylesheet Language Transformations (XSLT) 1.0, XML Path Language (XPath) 1.0, all of which are W3C Recommendations, and hosts of other essential components as well as applications of XML (such as MathML 2, XHTML 1.0 and XHTML Basic). Canonical XML provides the technology necessary for the successful completion of XML Signatures, which already has a host of supporting implementations.

Cooperative Effort between W3C and IETF Delivers Results

This is the first recommendation produced by the joint W3C/IETF XML Signature Working Group. Contributors include representatives from Ariba, Baltimore Technologies, Done360, IAIK TU Graz, IBM, Microsoft, PureEdge, Reuters, and the W3C technical team. The Working Group is still at work on XML Signatures, which already enjoys significant implementation, and will have more with the completion of the work on Canonical XML.

About the World Wide Web Consortium [W3C]

The W3C was created to lead the Web to its full potential by developing common protocols that promote its evolution and ensure its interoperability. It is an international industry consortium jointly run by the MIT Laboratory for Computer Science (MIT LCS) in the USA, the National Institute for Research in Computer Science and Control (INRIA) in France and Keio University in Japan. Services provided by the Consortium include: a repository of information about the World Wide Web for developers and users, and various prototype and sample applications to demonstrate use of new technology. To date, over 500 organizations are Members of the Consortium. For more information see


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