From: rcain@netcom.com (Robert Cain)
Date: Tue, 8 Feb 94 14:22:03 PST
To: cypherpunks@toad.com (cypherpunks)
Subject: Re: Crypto Regulation Reform
In-Reply-To: <9402052019.AA10570@vail.tivoli.com>
Message-ID: <199402082221.OAA10284@mail.netcom.com>
MIME-Version: 1.0
Content-Type: text/plain


Mike McNally sez:
> 
> 
> Robert Cain writes:
>  > A device can be made right now at lower cost
>  > than a computer modem, much lower, that could be inserted between any
>  > phone and the wall that would make it impossible, no matter what laws
>  > are in place, to tap either passively or acitively, communication that
>  > passes between two of these devices.  I know how to do it, could do it
>  > and probably will just for the fun of it at least.  
> 
> Uhh, could you tell us?

'Fraid not.  I want to patent it and profit from it.  As a
hardware/software development engineer I stand diametrically opposed to
the FSF gang.

> Sounds like quite a breakthrough.  Credit
> card sized?  Much cheaper than a modem, like $50 maybe?  And it
> digititizes and securely encrypts speech (full duplex?) on the fly?

Well, making it credit card sized and cheaper than a modem is not all
that difficult.  An AT&T VSELP chip based on their DSP1616 with some
firmware added for primative modem capability, some firmware for the
encryption and a couple of codec chips fits the bill nicely.  I do have
a breakthrough though and that is in the area of a key exchange
protocol that can detect an active spoof, a problem unsolvable in theory
(at least in the opinion of Whit Diffie, Marty Hellman and Ron Rivest)
but solvable to any desired degree of confidence in practice.  In fact
in the most common situation that I would expect it to be used, it is
provably secure against a spoof.  I can't say any more about how that
works but some fine mathematicians and some crypto names most of you
know have witnessed and validated it.


Peace,

Bob

-- 
Bob Cain    rcain@netcom.com   408-354-8021


           "I used to be different.  But now I'm the same."


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