XML dig. signatures: how to identify the root XML element?

Question

Hello, according to tutorials I need to do these two things to sign a XML document:
ref = fac.newReference("#invoice",
  fac.newDigestMethod(DigestMethod.SHA1, null));
        XMLObject obj = fac.newXMLObject(Collections.singletonList(content),
                "invoice", null, null);I need to create a general signing proces that will accept any XML file. In this piece of code I have "invoice" strings directly in the source code. Is it possible to replace them with some general strings? For both methods documentation reads "can be null" but I am getting the "XMLSignatureException: javax.xml.crypto.URIReferenceException: ResourceResolverException: Could not find a resolver for URI null and Base null".
I have also tried "/" - this should be URI for the root element in the XPath. This leads to "URIReferenceException: java.lang.NullPointerException".
I could "pre-parse" the XML and find the root element name but there must be "cleaner" method.
Thanks in advance

Answer 1

Hello, according to tutorials I need to do these two
things to sign a XML document:
ref = fac.newReference("#invoice",
fac.newDigestMethod(DigestMethod.SHA1, null));
XMLObject obj =
fac.newXMLObject(Collections.singletonList(content),
"invoice", null, null);
ed to create a general signing proces that will
accept any XML file. In this piece of code I have
"invoice" strings directly in the source code. Is it
possible to replace them with some general strings?
For both methods documentation reads "can be null"
but I am getting the "XMLSignatureException:
javax.xml.crypto.URIReferenceException:
ResourceResolverException: Could not find a resolver
for URI null and Base null".
I have also tried "/" - this should be URI for the
root element in the XPath. This leads to
"URIReferenceException:
java.lang.NullPointerException".
I could "pre-parse" the XML and find the root element
name but there must be "cleaner" method.I am not quite sure what you are trying to do. What do you mean by "replace
them with general strings"? If all you want to do is sign the entire contents of
an arbitrary XML document, you should probably create an enveloped signature. For
that you need to specify a URI of "" when creating your Reference (this indicates
the root of the document) and also specify an enveloped Transform. There is
an example of how to do this in the XMLDSig Tutorial (the genEnveloped example):
http://java.sun.com/javase/6/docs/technotes/guides/security/xmldsig/XMLDigitalSignature.html