[OpenID] Signing method for XRD

[Hans Granqvist]

> Once you digitally sign a document, though physically the document remains
> in tact and retains its content type, after the act of signing, it is really
> a frozen bunch of bits. And if you dont make that distinction you get into
> all sorts of tangles. And that was the mistake made by XMLDSig. In other
> words after signing the Content-Type should be binary, whatever you want to
> call it. After verification it takes up its original Content-Type.

In XML these two are equivalent:

<a     foo="1"  bar="2"/>

<a bar="2" foo="1"       />

A signing process needs to understand this, and that is what XML Dsig does.
XML was not defined to be a wire format.

Hans