From: tcmay@netcom.com (Timothy C. May)
Date: Tue, 26 Jul 94 00:57:19 PDT
To: cypherpunks@toad.com
Subject: Radio-activated locks...and protecting them
In-Reply-To: <199407260711.AAA10426@netcom.netcom.com>
Message-ID: <199407260757.AAA20761@netcom7.netcom.com>
MIME-Version: 1.0
Content-Type: text/plain


(I've changed the thread title from "CYPHERPUNKS TO THE
RESCUE"...after all, doesn't that describe _most_ of our threads?)

Norm Hardy wrote:

> At 14:43 1994/07/25 -0700, Sandy Sandfort wrote:
> >The questions are:  Could standard auto and garage door openers
> >easily be retrofitted?  Could a "crypto remote" with its own CPU
> >be made small enough to fit into a hand-held unit?  Could such a
> >system be made for a reasonable cost?
> ...
> Sounds like an application for a "challenge-response" system. But that
> would require transmission from garage unit to car unit.
> 

This is also the motivating idea behind "zero-knowledge interactive
proof systems." Systems in which interception of the sent information
is useless to the attacker.

As Norm mentions, the "lock" (which can be many things besides garage
door openers, e.g., proximity-based door locks, or auto locks
themselves, or gun locks, etc.) needs to "do something" that
essentially creates a problem that only the key can solve. A simple
example is public key-private key: the lock demands that a message be
decrypted, or signed, or whatever, by the key.

A good project for Cypherpunks as a group to work on, which I took to
be Sandy's meaning? Well, we don't have any real group projects, and
this is unlikely to be one.

A good project for some particular Cypherpunk? Maybe. I understand the
electronic lock folks (card locks, hotels, etc.) have crypto expertise
of varying extents (and bluntly, probably more than most of us have)
and they certainly have the expertise in other areas.

Maybe an existing chip could be added to "Genie"-type openers.

But let's not forget that such a project, if it succeeded, would
result in legislation requiring Garage Door Opener Escrow.

--Tim May


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Timothy C. May         | Crypto Anarchy: encryption, digital money,  
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