This informative W3C Working Group Note describes XML digital signature processing rules and syntax. XML Signatures provide integrity, message authentication, and/or signer authentication services for data of any type, whether located within the XML that includes the signature or elsewhere.

XML Signature 2.0 includes a new Reference processing model designed to address additional requirements including performance, simplicity and streamability. This "2.0 mode" model is significantly different than the XML Signature 1.x model in that it explicitly defines selection, canonicalization and verification steps for data processing and disallows generic transforms. XML Signature 2.0 is designed to be backward compatible through the inclusion of a "Compatibility Mode" which enables the XML Signature 1.x model to be used where necessary.