From: "Dave Emery" <die@pig.die.com>
Date: Mon, 3 Feb 1997 22:53:10 -0800 (PST)
To: cypherpunks@toad.com
Subject: Re: FCPUNX:ecure Phones (fwd)
Message-ID: <9702040652.AA11304@pig.die.com>
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Forwarded message:
>From die Tue Feb  4 00:30:04 1997
Subject: Re: FCPUNX:ecure Phones
To: eli@gs160.sp.cs.cmu.edu (Eli Brandt)
Date: Tue, 4 Feb 1997 00:30:04 -0500 (EST)
From: "Dave Emery" <die@pig.die.com>
Reply-To: die@die.com
In-Reply-To: <199702040425.UAA08359@blacklodge.c2.net> from "Eli Brandt" at Feb 3, 97 11:24:03 pm
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	Don't think I will bore the list with it,

	But a slightly more complex version of this scheme was one of
the major tactical medium security voice scrambling systems used
by the US in the 70's and 80's and even to a slight extent into
the 90's on military radio circuits.   The military version is
called Parkhill and the crypto gear is the KY-65 and KY-75.

	At one time (in the 70's) it was used for at least secret
traffic.  It was downgraded a couple of times since and is now
considered obselete and compromised.  A Parkhill crypto box
can be seen in the NSA museum...

	The NSA version used time inversion (playing voice samples
backwards) and faster shuffling than this one does, and possibly
a more secure key generator.  But it is rumored to have been
broken by more than one opponent, perhaps including drug cartels.

	Its appeal and why it was so extensively used for a while is
that it interfaces to normal voice radio gear at the audio input
and output level rather than requiring different modulations and
complex digital modems integrated into the radio.  It also gives
pretty good speech quality and speaker recognition.

	Its primary replacement is the ANDVT digital voice terminal
which takes advantage of modern DSP technology to implement modems
usable over radio links and vocoders which can produce acceptable
speech at 1200 or 2400 baud.


							Dave Emery
							die@die.com