Also you would probably need a permit to own thermite. I don't think there's a problem with owning it or making it -- only (perhaps) selling it and transporting it; thermite is not strictly an explosive. You may wish to consider alternate ways of destroying the data, especially if you wish to ever transport the device on a commercial airline; if you've only got one RAM device that has critical data in it, then simply arrange for the battery backup circuit to have a "high current mode", perhaps feeding more of the
cryptosystem: analog input and output, for use as a phone line scambler. Such a system could be manufactured for not too much money, I think. It Let's see -- an ISDN-quality (quality? I use the term loosely) codec should be under $50 single quantity, the data rate isn't very high so you don't need much of a CPU (6811 might even be enough, and
pins -- a "light emitting RAM" should be just as blank as one burned
through by thermite.
they're easy to interface to things -- lots of on-chip I/O). You'd
need a modem-style encoder for the output (running digital from
box-to-box -- "analog" scrambling (Time or Frequency domain) is way
too easy to break) so maybe another $50 DSP chip... after all, you
don't need to support 30 different baud rates, just one data rate with
perhaps a low-line-quality backoff. The connectors and the box are
probably the major recurring cost (the chip prices will go way down in
quantity.) Am I missing anything? The technology level of the Newton
seems to be a bit of overkill (unless you actually want that kind of
user interface.)
_Mark_