some days ago c14n-r was released.
From the readme:
“C14N-r stands for ‘xml canonicalizer for ruby’. It implements the
Canonical XML Version 1.0 recommendation from the w3c. c14n-r is a
sub-project from wss4r, an implementation of some web service security
See http://www.w3.org/TR/xml-c14n for more information about canonical
Download it at http://www.rubyforge.org/projects/c14n-r