EURion constellation
A number of new designs of banknotes contain a pattern known as the EURion constellation which can be used to detect their identity as banknotes to prevent counterfeiting using modern inexpensive digital scanners, colour printers, and image processing software. This feature prevents the user from scanning notes, or even printing. It was discovered after some users tried to scan euro banknotes in image editors such as Adobe Photoshop, or Paint Shop Pro.
The EURion constellation consists of a pattern of five small circles, which is repeated across areas of the banknote at different orientations. The name, coined by Markus Kuhn in 2003, is a portmanteau of Orion, a constellation of similar shape, and EUR, the euro's ISO 4217 designation.
The EURion constellation was first detected on the new Euro banknotes. It was then found to have been printed on (obsolete) Deutschmark notes as well. The EURion constellation also appears on recent British banknotes, the backs of the new U.S. $20 bill and $50 bill, the current (post ca 1998) Danish banknotes, and all of the 2001 series of Canadian bills.
According to an article in Wired, the banknote detection code was designed by the Central Bank Counterfeit Deterrence Group and supplied to companies such as Adobe as a binary module. However, research by Steven Murdoch and others appears to show that the bankmark detection code also detects other features of banknote design.
External links
- http://www.cl.cam.ac.uk/~mgk25/eurion.pdf (in Adobe Acrobat format)
- http://www.freedom-to-tinker.com/archives/000497.html
- http://www.wildspark.com/eurionize/ - Add the EURion Constellation to a PostScript document
- http://www.wired.com/news/print/0,1294,61890,00.html
- http://www.nationalbanken.dk/DNDK/money.nsf/side/200-kr!OpenDocument - current danish currency