The man-in-the-middle thing can happen irrespective of what OPES does
or doesn't do, in the absence of end-to-end security, say TLS.
I fail to see how OPES's charter and its yet-to-be-developed protocol
would worsen the existing situation.
- if the interfaces designed by OPES make it easier for intermediaries
to process traffic with the authorization of the edges, they might
also make it easier for intermediaries to do so without such
authorization. however, with appropriate design, it may be possible
to discourage use of OPES without consent of an endpoint.
(it wouldn't discourage modification of content by other means, but
at least OPES wouldn't serve to encourage such modification)
- appropriate clarification of OPES's charter would discourage those
who want to develop tools for unauthorized modification, from
trying to further those aims within the context of OPES.
- appropriate restriction on OPES's charter would explicitly forbid
OPES from providiing explcit support for unauthorized interception
of traffic that are not needed when authorization is present.
- appropriate restrictions on OPES's charter, along with language
included in any documents that OPES produces, would make it clear
that IETF does not endorse unauthorized interception and alteration
of network traffic.
Keith