"The music industry responded to illegal file-sharing with digital rights management (DRM) techniques..."

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The music industry responded to illegal file-sharing with digital rights management (DRM) techniques that prevented a song from playing on an unauthorised device. Could companies that sell physical products do the same?

One option is placing a marker on objects that a 3D scanner could detect and which would stop it operating. In 2002 University of Cambridge computer scientist Markus Kuhn discovered this technique is already used to prevent banknotes from being photocopied, but he says it would not work for 3D scanners as pirates could simply cover the marker with tape.

He suggests borrowing an alternative method from music DRM. Some companies watermark their audio files by encoding copyright information in frequencies outside the range of human hearing, which are normally discarded by compression algorithms. Kuhn says the equivalent in physical objects is the mechanical tolerances used in manufacturing - one side of an object might be specified as 300 ± 1 millimetres, for example. A marking algorithm could etch a tiny pattern in the unused section that a scanner would detect.