unforgeable optical tokens?

[R. A. Hettinga]

--- begin forwarded text


Status: RO
User-Agent: Microsoft-Entourage/10.1.0.2006
Date: Sun, 22 Sep 2002 14:40:58 +0100
Subject: Re: unforgeable optical tokens?
From: "David G.W. Birch" <dgw-lists at birches.org>
To: Bob Hettinga <rah at shipwright.com>,
	Digital Bearer Settlement List <dbs at philodox.com>

On 20/9/02 6:09 pm, Perry e-said:

> A couple of places have reported on this:
>
> http://www.nature.com/nsu/020916/020916-15.html
>
> 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 remember being shown a similar system from a Dutch company four or five
years ago. Same idea, except that they were using the alignment of fibres
trapped in the resin (rather than bubbles).

It's an interesting way of making an unforgeable token, but I think its
practical applications are more in brand protection (labels for designer
sunglasses and so on) rather than in cryptography.

Regards,
Dave Birch.

-- 
-- My own opinion (I think) given solely in my capacity
-- as an interested member of the general public.
--
-- mail dgw(at)birches.org, web http://www.birches.org/dgwb

--- end forwarded text


-- 
-----------------
R. A. Hettinga <mailto: rah at ibuc.com>
The Internet Bearer Underwriting Corporation <http://www.ibuc.com/>
44 Farquhar Street, Boston, MA 02131 USA
"... however it may deserve respect for its usefulness and antiquity,
[predicting the end of the world] has not been found agreeable to
experience." -- Edward Gibbon, 'Decline and Fall of the Roman Empire'

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