Binary Data in XML?

Mike Sample (msample@opentext.com)
Fri, 17 Oct 1997 14:30:03 -0700

Is there a standard way to include binary data directly within an
XML/RDF document? Or must one use indirection or ad-hoc encoding such
as:

<foo href="http://somewhere.com/the_data.bla"/>

or
<foo enc="hex">A103EF92B7</foo>

Thanks,

Mike Sample