unforgeable optical tokens?

[Steven M. Bellovin]

In message <20020921063415.6F76030752 at lion.ninthwonder.com>, eli+ at zimbs4.srv.cs
.cmu.edu writes:
>Perry E. Metzger wrote:
>> An idea from some folks at MIT apparently where a physical token
>> consisting of a bunch of spheres embedded in epoxy is used as an
>> access device by shining a laser through it.
>
>I can't dig up the memory, but I think I heard of a similar idea --
>random structure in transparent solid, difficult to copy -- used in
>some kind of tag or seal for nuclear security.  Can anyone remind me
>what this might have been?
>

A fair number of years ago, I saw something like this proposed for 
non-proliferation seals on nuclear reactors.  The scheme then (I 
believe I saw it in Science News) was that International Atomic Engergy 
Agency inspectors would use a length of randomly-twisted multi-strand 
fiber optic cable and use it to seal a door that they opened to verify 
that the reactor in question wasn't being used to build weapons.  They 
then shine a light in one end, and photograph the other.  When they 
come back, the repeat the photographic process, so that they can see if 
anyone has removed their seal -- say, to get at the irradiated, 
plutonium-containing fuel rods.

		--Steve Bellovin, http://www.research.att.com/~smb (me)
		http://www.wilyhacker.com ("Firewalls" book)



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