[keyassure] Binding to full TLS encapsulation or STARTTLS

[Matt McCutchen <[e-mail]>]

I realized that TLSA as we are currently discussing does not bind keys
to the use of full TLS encapsulation or STARTTLS.  I'm thinking this is
OK because it would be pretty ridiculous to multiplex different services
based on the use of full encapsulation or STARTTLS, and clients
generally do not ascribe security significance to the use of one or the
other.  E.g., if I bind a key to _3141._tcp.example.com for a service
that uses STARTTLS, I can't think of any scenario in which a client
trying to use full encapsulation would be harmed if a MITM allowed it to
succeed by performing the STARTTLS part directly with the server.  It
might be nice to prevent web browsers from talking to STARTTLS services,
but that would be far from a complete solution to the problem of
browsers being a loose cannon for arbitrary connections, nor is it our
responsibility to solve that problem here.

Sanity check?

-- 
Matt