[wsrp][security] High-level scenario

Please see the attached high-level scenario outlining security
considerations.  This is intended to be a seed for discussion in tomorrow's
telecon; additional scenarios need to be identifed and then fleshed out with
more details.  As was mentioned in today's joint wsia/wsrp interfaces call,
we should be looking at other standards efforts in the security space(SAML,
etc) and how they can address the needs we define in the WSRP context.
Ideally we could leverage those efforts and not need to invent anything that
is specific to WSRP.

Comments?

 <<WSRP Security Scenario.doc>>