August 1, 2005. Copyright Graphic News, All rights reserved.

3D barcodes to identify stolen valuables

August 1, 2005 -- Graphic News, London: Microscopic barcodes that store encrypted information could protect diamonds, works of art, and other high-value items by making history of ownership easy to prove if they are stolen.
Scientists at BritainÕs National Physical Laboratory (NPL) at Teddington, near London, used nanotechnology to develop a barcode on a cube that can hold the equivalent of 1.5 million words, or two King JamesÕ bibles.
This tiny cube of silicon -- just 30 micrometres across, or about a third of the width of an average human hair -- is coated with a 100-nanometre-thick layer of polymethyl methacrylate, a transparent plastic.
In the world of nanotechnology size can be hard to visualize: a nanometre is equal to one billionth of a metre, or a millionth of a millimetre, and a micrometre is a thousandth of a millimetre. The limit of human vision is about half the width of a single hair Ð about 50 micrometres.
To store the information an electron beam is used to drill 90,000 small squares into the plastic coat of each face at five different depths. The position and depth of each square is unique, so data can be encrypted and stored digitally, in a similar way to music stored by ÒlandsÓ and ÒpitsÓ in the groove of a CD.
Once created, the nanobarcode can be glued to hard surfaces or woven into the canvas of paintings.
To read the data the cube is scanned line by line using an electron microscope.
ÒYou cannot see or feel the cube -- even if you roll it between your finger and thumb,Ó said NPL researcher Dr Alexandre Cuenat. Criminals are unlikely to realise the item is protected -- and they wonÕt be able to read or duplicate the code, as it is encrypted and practically unbreakable. 
 The nanobarcode could also establish the provenance of other high-value items, such as antiques, bearer bonds and banker's drafts.
/ENDS
Source: New Scientist