From: Kent Crispin <kent@songbird.com>
Date: Wed, 9 Apr 1997 15:05:10 -0700 (PDT)
To: Lucky Green <shamrock@netcom.com>
Subject: Re: Black box attacks (was Re: Crypto-Dongel)
In-Reply-To: <3.0.32.19970409134223.007296b8@netcom13.netcom.com>
Message-ID: <19970409150210.65475@bywater.songbird.com>
MIME-Version: 1.0
Content-Type: text/plain


On Wed, Apr 09, 1997 at 01:45:19PM -0700, Lucky Green wrote:
> At 12:35 PM 4/9/97 -0400, Cynthia H. Brown wrote:
> >If you're trying to destroy a standard IC, why don't you just hook up the
> >power and ground pins to a 120V AC outlet? 
> 
> You are unlikely to have AC in a system by the time the tamper detector
> senses an intrusion. Similar problems apply to arcs and anything based on
> discharging a large capacitor.

I don't think power is the problem -- you could always include a 
small rechargable battery in the device, which would be plenty to fry 
an IC, given suitable support circuitry.  The real problem is the 
logic of the tamper detector itself.  How does it "detect 
tampering"?  You would want it to detect mechanical tampering, of 
course, but that's a non-trivial engineering proble.

-- 
Kent Crispin				"No reason to get excited",
kent@songbird.com			the thief he kindly spoke...
PGP fingerprint:   B1 8B 72 ED 55 21 5E 44  61 F4 58 0F 72 10 65 55
http://songbird.com/kent/pgp_key.html