[osis-core] XML Signature [<signature> in <work>]

[Todd Tillinghast]

Patrick and Steve,

It occurs to me that an valuable feature to add to the <work> element
would be a <signature> element that would contain a "digital signature"
of the work.  Basically a digest of the text.

The value would be that if a referencing document included the
<signature> element, a matching document would have to have a matching
<signature> element.  The presumption would be that the digest in the
<signature> would be a digest of the document (probably qualified by an
XPath expression).

This would also give us the opportunity to provide a non-intrusive
mechanism for signing OSIS content.

The proposal would be to add an element <signature> to <work> whose
mixed="false" children are instance of elements defined by the w3c XML
Signature specification.

At this late date, I don't think this can make it into OSIS 2.0 but
might be a nice addition for a minor release after the January meeting.

Thoughts?

Todd