unforgeable optical tokens?

[Perry E. Metzger]

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.

On the surface, this seems as silly as biometric authentication -- you
can simply forge what the sensor is expecting even if you can't forge
the token. Does anyone know any details about it?

-- 
Perry E. Metzger		perry at piermont.com

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