The Finch Formerly Known As Gold

21 September 2002

Decrypt this

Up until now, cryptographic keys have been derived from mathematical functions. Now MIT researchers have figured out a way to derive keys from actual physical objects: they've embedded glass beads in small blocks of epoxy, directed a laser beam into their midst, and then converting the interference pattern from the beam into a string of approximately 2400 bits.

Since no two physical objects are absolutely identical, the little epoxy blocks can serve as identification keys or as verification for security devices. You'll probably be carrying something like this yourself in the next ten years.

Update, 7:05 am, 24 September: Fusilier Pundit reports the following:

"Scientific American had a little sidebar story long long ago, on a technique the US developed to authenticate serial numbers on cruise missiles. They sprayed a mixture of lacquer and microscopic ground glass particles over the serial numbers, and photographed each one from several angles. The reflection patterns of each marking were unique and reproducible (duplicate the flash intensity and color and the angle of incidence) but not practicable to duplicate. I'd venture this was 1987."

Evidently, there is truly nothing new under the sun.

Posted at 9:18 AM to PEBKAC

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