SOAP Version 1.2 Message Normalization
Sun and Microsoft in joint publication shock: SOAP Version 1.2 Message Normalization.
From the abstract: “SOAP 1.2 intermediaries have some license when reserializing messages that pass through them. This document defines a transformation algorithm that renders all semantically equivalent SOAP messages identically. The transformation may be used in conjunction with an XML canonicalization algorithm prior to the generation of a message digest in producing XML digital signatures that are sufficiently robust to survive passage through one or more SOAP intermediaries.”