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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" <[EMAIL PROTECTED]> To: Bob Hettinga <[EMAIL PROTECTED]>, Digital Bearer Settlement List <[EMAIL PROTECTED]> 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: [EMAIL PROTECTED]> 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' --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]