Have you ever come across a fake Euro banknote? Well, most of us probably have (at least those of us who live in the European Union, like me) - more than 300 thousand Euro banknotes are falsified every year.
Well, one of the eleven security measures of Euro banknotes is the check digit in the serial number that is located in the back of the note that should look something like X01587275921, with some research I’ve developed an algorithm in PHP, that tells you if the specified Euro banknote serial number is valid or not, and therefore if the note is (possibly) valid or not.
For my research I’ve read the portuguese book from Jorge Buescu - Da Falsificação De Euros Aos Pequenos Mundos, and, some articles from the European Central Bank - you can see a very nice flash animation regarding some of the disclosed security features implemented in Euro banknotes here.
Basically what this algorithm does is to replace the first letter of the serial number by a number (each letter represents where the banknote is originally from), then it calculates the sum of all digits. If the remaining of the division of that sum by 9 is 0 then your note is valid.
You can get the source code here, I also made the script avaliable for online tests, here are some examples:
I also found a very interesting thing - this is what it happens when you try to open a banknote image in Adobe Photoshop:
The method which Photoshop uses to recognize a banknote images is a mystery to me, maybe EXIF information stored with the image? I went to http://www.rulesforuse.org/ but couldn’t find anything - if anyone knows, please, share the knowledge!
I’m going to find out about the PS note recognition, if I find something I’ll tell you.
Thanks to aNieto2K blog I’ve learn about the EURion Constellation.
I,ve got this banknote in a finnish bank in Helsinki. Banknote would have been in circulation, if I didn,t find it. Specialist Auctions tried to sell my banknote at 10,000,000.00£s price, but only with the list of the errors: light flowers to the left below the brown lining, in the brown lining below a HOLE, near 5 to the right a light cross and in the middle 0 also a light cross, all around an inside the house light and dark brown tracks, to the right the house the roof down, there is also a HOLE, in the basement brown errors and the whole banknote is disragged, If you are interested in it, please e-mail to me your e-mail adress, you´ll get the digipix of mt note