Can we have the option of not canonicalising the signed XML file?

[Weiwu Zhang]

If I undrestood XMLDSIG correctly, the signature is applied on the digest 
of the node, which is canonicalised, but it doesn't have to be enveloped 
in a canonicalised file.

That is, it should be possible to append signature to an XML without 
changing other parts of the XML file at all and it would still be valid.

This is important in the case the XML file needs to be viewed or, that it 
contains errors that can only be captured at run time, and not 
schema-detectable - in our use-case, you need blockchain data to figure 
out if there is an error in an XML file that describes a blockchain token.

In such cases, it's important to report a line number of the error that 
the developers can use to trace in their original, unsigned XML file.

If such an option is possible, I actually feel it should be the default. 
XML use-cases are already complicated and having to deal with the 
canonicalised form is another burden on the learning curve. Making it 
transparent is one less things to keep in mind for the developers. 
Besides, why would enveloped and external xmldsig be any different (where 
the external one didn't require you to change the file structure, but the 
enveloped one resulted in dramatically changed canonicalised form).

Thanks for the great work by the way! Love from Sydney, Australia.