EURion constellation
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The EURion constellation is a pattern of little circles found on a number of recent banknote designs. It is added to help software detect the presence of a banknote in a digital image. Such software can then block the user from reproducing banknotes to prevent counterfeiting using colour photocopiers.
Description
The name "EURion constellation" was coined by Markus Kuhn, who discovered the pattern in early 2002 while experimenting with a Xerox colour photocopier that refuses to reproduce banknotes. The word is a portmanteau of Orion, a constellation of similar shape, and EUR, the euro's ISO 4217 designation.
The EURion constellation first described by Kuhn consists of a pattern of five small yellow, green or orange circles, which is repeated across areas of the banknote at different orientations. The mere presence of five of these circles on a page is sufficient for some colour photocopiers to refuse processing. Andrew Steer later noted simple integer ratios between the squared distances of nearby circles, which gives further clues as to how the pattern is meant to be detected efficiently by image-processing software.
The EURion constellation is most prominent and was therefore first recognised on the 10 Euro banknote.
Some banks integrate the constellation tightly with the remaining design of the note. On German banknotes, the EURion circles formed the innermost circles in a background pattern of fine concentric circles. On the front of British £20 notes, they appear as green heads of musical notes. On U.S. dollar bills, they form the digit zero in little yellow numbers that show the value of the note.
Technical details regarding the EURion constellation remain kept secret by its inventors and users. A patent application suggests that the pattern and detection algorithm were designed at OMRON Corporation.
Usage
The following table lists the banknotes on which the EURion constellation has been found so far:
| Currency | Notes with EURion constellation | Notes without EURion |
|---|---|---|
| Armenian dram | 1000 dram (2001), 5000 dram (2003), 10000 dram (2003) | 20000 and commemorative 50000 dram |
| Austrian schilling | 500 and 1000 schilling (1997) | 20, 50, 100, and 5000 schilling |
| Australian dollar | Commemorative (2001) | Regular banknotes |
| Belgian franc | 500 francs (1998), 1000 francs (1997), 10000 francs (1997) | 100, 200, and 2000 francs |
| British pound | £5 (2002), £10 (2000), £20 (1999) | £50 (not yet upgraded) |
| Bulgarian lev | All (1999) | |
| Canadian dollar | All of "Canadian Journey" series (2001) | |
| CFA franc | All (both West African and Central African, 2003) | |
| Comorian franc | 1000 and 2000 francs (2005) | 500, 2500, 5000, and 10000 francs |
| Croatian kuna | 5, 10, 20 kuna (2001), 50, 100, and 200 kuna (2002) | 500 and 1000 kuna |
| Danish krone | All since 1997 series | |
| Djiboutian franc | 1000 francs (2005) | 2000, 5000, and 10000 francs |
| Dutch gulden | 10 gulden (1997) | 25, 50, 100, 250, 1000 gulden |
| Egyptian pound | LE 5 (2002), LE 10 (2003), LE 20 (2001), LE 50 (2001), LE 100 (2000) | 25 piastres, 50 piastres, LE 1 |
| euro | All (2002) | |
| Faroese króna | All (2001) | |
| French franc | 100 francs (1997) | 50, 200, and 500 francs |
| German mark | 50, 100, 200 mark (1996-2002) | 5, 10, 20, 500, 1000 mark |
| Japanese yen | Commemorative ¥2000 (series D, 2000), all of series E (2004) | |
| Norwegian krone | All (1999) | |
| Malagasy ariary | 100, 200, 500, 1000 ariary (2004) | 2000, 5000, 10000 ariary |
| Mexican peso | 00 (2004) | , , 0, 0, 0 |
| Moroccan dirham | All (2002) | |
| Renminbi | ¥1 (2004) and 2005 revision of ¥5 and above | |
| Romanian leu | All (2005) | |
| Singapore dollar | All (1999) | |
| Slovak koruna | 200, 500, 1000, and 5000 korún (1999) | 20, 50, and 100 korún |
| South African rand | All of 2005 series | |
| South Korean won | ₩1000 (2007), ₩5000 (2006), ₩10000 (2000 and 2007) | ₩1000 (1983-2007) |
| Swedish krona | Kr 50 (2006), Kr 100 (2001), Kr 500 (2001), Kr 1000 (2006) | Kr 20 |
| Tunisian dinar | 10 dinars (2005) | 5, 20, and commemorative 30 dinars |
| Turkish new lira | All (2005) | |
| United States dollar | (2008), (2006), (2003), (2004), 0 (after new ) | , , (-2008), 0 |
Other banknote detection mechanisms
Users of recent versions of image editors, such as Adobe Photoshop or Paint Shop Pro, discovered that these also refuse to print banknotes. According to an article in Wired magazine, the banknote detection code in these applications, called the Counterfeit Deterrence System (CDS), was designed by the Central Bank Counterfeit Deterrence Group and supplied to companies such as Adobe as a binary module. However, experiments by Steven J. Murdoch and others showed that this banknote detection code does not rely on the EURion pattern. It detects other features of banknote designs that have yet to be described in public.
References
- Markus Kuhn: [The EURion constellation]. Security Group presentation, Computer Laboratory, University of Cambridge, 8 February 2002.
- Mitsutaka Katoh, et al.: Image processing device and method for identifying an input image, and copier scanner and printer including same. OMRON Corporation, [U.S. Patent 5845008].
External links
- [Instructions and video for defeating this protection using Adobe Photoshop]
- [Discussion about the technology deployed in Photoshop to prevent currency image loading]
- [Add the EURion Constellation to a PostScript document]
- [Wired Magazine]
- [Demonstration that the CDS does not use the EURion constellation and also other related information]
- [Current Danish currency]
- [The rules for (American) currency image use]
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