7.2. Signing SOAP messages

Let’s get back to the focus of this chapter: the use of digital signatures to verify the integrity of messages. As we discussed in the previous section, signing XML documents such as SOAP messages is more complicated than signing an arbitrary message. In addition to using XML canonicalization to cancel variations in XML syntax, we need to worry about:

• How we can represent the signature and its metadata within the signed XML document itself

• How we can sign selected parts of an XML document as opposed to signing its entirety.