From: mjr@tis.com (Marcus J Ranum)
Subject: Re: Let's build software cryptophones for over the internet...
Organization: Trusted Information Systems, Inc.
Lines: 48
NNTP-Posting-Host: sol.tis.com

Graham Toal <gtoal@gtoal.com> writes:
>Yes.  I'm not sure if my xposting to comp.speech made it to here too, but
>I've found that a low sample rate (3300 samples/sec at 8 bits per sample)
>plus the pd 'shorten' lossless sound compression code actually does get
>speech into 14.4K with a simdgen left over.  This is *definitely* worth
>working on, folks.  And shorten works in well under real-time.

	I don't think that this should be worked on just in the context
of cryptography. That's sure to pose all sorts of problems for all sorts
of people.

	What's needed is for someone to develop a portable telephone
quality speech<->RS232 converter. Imagine, if you will, a little box that
takes data on its serial port and puts out sound, and takes sound and codes
it to signals on its serial port. Full duplex. Now, this device is not a
cryptographic device. It's a portable poor man's sound blaster or whatever
you want to call it. It's got loads of perfectly legitimate applications
for:
	a) speech synthesis (with a few nifty libraries and some samples)
	b) speech recording for electronic messaging
	c) building voicemail systems
	d) internet talk radio
	e) internet relay chat

	Of course, some of the electronic messaging in item b might be
encrypted, possibly realtime, but that's the user's decision. One would
need 2 of these talky boxes and a pair of modems and some kind of cutout
to switch over, and some code on, say, a 486 laptop.

	I'd really like to see such a thing developed so that interactive
internet talk radio could be done. Ideally, though, it should be a general
purpose device. It should be a general purpose enough device that nobody
should be able to balk at its widespread use. Obviously, to make it easy
for homebrewers, it should use pretty common hardware.

	It's interesting to note that I'd already talked with a couple
of folks about building such a thing, before this whole clipper thing
started. I even went so far as to track down a couple of folks who are
able to make sample units, given incentive and some time. I'd envisioned
finding a couple of folks interested in such a project and helping fund
development of a public domain board layout and parts set, that could
be published in the form of CAD drawings for a couple of major CAD
packages, and in PostScript.

	Anyone interested? I'll start a provisional mailing list. Let
me know if you want on.

mjr.
