Re: [TLS] EXTERNAL: Re: integrity only ciphersuites

[Lyndon Nerenberg <[e-mail]>]

There is one other -- admittedly esoteric! -- place where a NULL
cipher would he useful: Amateur Radio applications.

By law, we are forbidden from transmitting encrypted traffic, yet
there are use cases where integrity protection in the absence of
data content protection would be of benefit.

A very common case is controlling a remote repeater site.  Using
data integrity coupled with a client X.509 certificate means I can
restrict access to the "control" service at the site.  It's fine
if people see the traffic in flight, since they won't be able to
authenticate to do a replay or issue their own commands.

This is a distinct improvement over existing control schemes, which
typically use DTMF touch tone commands that anyone can trivially
figure out.

As I said, a very niche case.  It has been done before, using IPsec
AH, but that's extremely heavy weight, and a pain to configure and
maintain.  It also requires a full-on IP fabric, whereas TLS can
be implemented directly on top of AX.25 sessions, which represent
the vast majority of amateur radio packet data links (which I
acknowledge puts this outside the realm of the Internet, and therefore
the IETF).

--lyndon  (VE7TFX)