🚀 go-pugleaf

Someone posted an idea about digitally encrypting phones, cellular
phones in particular, by digitizing the signal and using a
conventional end to end cryptosystem, following which we got this...

gilchr@ee.ualberta.ca (Andrew Gilchrist) writes:
>
>The system you describe cannot be implemented on current cellular
>phone systems in real-time.

Mr. Gilchrist is rather mistaken.

In fact, you can buy systems to digitally encrypt your cellular
communications right now. AT&T sells such a unit, for instance,
although they will only sell the ones that use really good encryption
to Government agencies. The unit in question is just one of their
normal units for digital encrypted telephony over normal phone lines
with a cellular transmitter attached.

There is nothing infeasable about building encrypted phone units.
Modems now hit 14 kilobaud and even higher with the new V.Fast units
in test (24kbaud is my understanding), whereas excellent voice can be
transmitted digitally over a 9.6kbaud bandpass given modern
compression techiques like CELP (codebook excited linear prediction).
Given the ability to digitize voice in real time and compress it down
so it needs low bandwidth, all one need do is apply an encryption
system (most conventional cryptosystems work orders of magnitude
faster than is needed even on wimpy hardware) and squirt the signal
out a V.32bis or similar modem, and, voila, encrypted telephony, and
in real time.

>A standard phone scrambler would be much easier to get/use/etc.

If "standard" means analog, well, analog phone scramblers are almost
all easily broken, and are pretty poor in general. Why use one when
digital techniques that are virtually unbreakable are available?
--
Perry Metzger		pmetzger@shearson.com
--
"They can have my RSA key when they pry it from my cold dead fingers."
Libertarian Party info: Phone 1-800-682-1776, E-Mail 345-5647@mcimail.com