From:	CSBVAX::CSBVAX::MRGATE::"SMTP::PYRITE.RUTGERS.EDU::SECURITY" 16-MAR-1989 22:31
To:	MRGATE::"ARISIA::EVERHART"
Subj:	Re: Simplex locks


Sender: security@pyrite.rutgers.edu
Date: Thu, 9 Mar 89 00:29:28 EST
From: deh@eng.umd.edu
Subject: Re: Simplex locks
To: nichols@cbnewsc.att.com
Cc: security@pyrite.rutgers.edu

The number of combinations can be cut down quite a bit by spraying 
or dusting the button tops with an organic dye (or whatever) that 
will display pretty colors when illuminated with UV light. I always
prefered a coupld of strange organic dyes used in dye lasers, but 
they are expensive, and a lot of comon household things work just
as well (the proof is left as an exercise for the reader). For a 
portable UV light source, you can get fancy, but I like the little
EPROM eraser lights. Small, portable, and intense. A battery powerd
device would be better of course if 120VAC is not available in the
target area. 

In any case, the buttons without powder left on them are the 
ones that you want to play with. This works great in elevators
that have button code systems in them for after hours use. The 
MIT Media Lab is a good example of such a facility (I wonder if
they still glow over there?). 

Doug