What about through SDR? ie. http://nuand.com/ I mean, 'subscriber' seems to indicate a layman, but SDR isn't too complex to get running for someone with a modicum of electronics experience - especially in this day and age, where oscilloscopes and frequency analysis is available to anyone with some Google-fu. On Sat, Jun 15, 2013 at 11:11 AM, Jay Ashworth <jra@baylink.com> wrote:
----- Original Message -----
From: "Scott Helms" <khelms@zcorum.com>
Is it possible? Yes, but it's not feasible because the data rate would be too low. That's what I'm trying to get across. There are lots things that can be done but many of those are not useful.
I could encode communications in fireworks displays, but that's not effective for any sort of communication system.
At this point, of course, we hearken back to the Multics system, which needed -- in order to get the B1(?) common criteria security rating that it had -- to prevent Covert Channel communication between processes of different security levels *by means as low-bandwidth as sending morse code by modulating the system load*.
So I don't think "there's too little bandwidth" is a good enough argument, Scott.
But there's a much more important issue here:
In some cases, like the Verizon Wireless 4G puck I mentioned earlier, manufactured by ZTE, *you can't see the back side of the device*. There's nearly no practical way for a subscriber to know what's coming out of the 4G side of that radio, so it could be doing anything it likes.
Verizon Wireless proper could know, but they have no particular reason to look and, some might argue, lots of reasons not to want to know.
Cheers, -- jra -- Jay R. Ashworth Baylink jra@baylink.com Designer The Things I Think RFC 2100 Ashworth & Associates http://baylink.pitas.com 2000 Land Rover DII St Petersburg FL USA #natog +1 727 647 1274