= Euro banknotes security features

Euro banknotes (design "T 382") were designed by Austrian Robert Kalina in 1996.
There are two series (the second is called "Europa").
And there is one of three possible signatures on it: Wim Duisenberg (2001-2003), Jean Claude Trichet (Nov 2003-Mar 2012), Mario Draghi (Mar 2012 or later).
The security features include see-through numbers (the 5/10/20/50/100/200/500 numbers on the note) only in the first series.
In the second series emerald digits were used (the lower number changes its color as the angle changes).
Magnetic ink is used for the rightmost church window on the €20 note.
The face of Europa is shown as a hologram (can be seen best with backlight).
The EURion constellation is a constellation of orange dots on the note. Its significance is unclear (i.e. kept secret).
Microprinting is used e.g. for the texture lines to the bottom, like those aligned to the right of ΕΥΡΩ mark on the €5 note, consist of the sequence "EURO ΕΥΡΩ" in microprinting.
People of impaired sight can distinguish notes by size and raised print (of the number).

1. Consider this second series serial number of a €10 note: "NA5432830525".
2. 'N' refers to the producing country. 'N' refers to Austria. 'N's ASCII code is 78. Austria's checksum is 3. The ASCII code of 'A' is 65.
3. The 9-sum is defined as adding the last two digits and adding the result to the remaining part times 10, until a value smaller 10 is given. "123" becomes "15" becomes "6". "56789" becomes 5670 + 17 = "5687" becomes 560 + 15 = "575" becomes 50 + 12 = "62" becomes "8".
4. First check: The sum of the digits (with the second letter's ASCII code coming as prefix) modulo 9 is the country's checksum. 65 + 5+4+3+2+8+3+0+5+2+5 gives 48. Modulo 9? We can iterate again. 4 + 8 = 12. 1 + 2 = 3. So digits modulo 9 is 3. This is also the country's checksum. Test passed.
5. Second check: The 9-sum of 'N's ASCII code (=78) is 6. The 9-sum of the sum of digits (= 48) is 3. The 9-sum of 6 + 3 = 9 modulo 9 is 0. It is required to be 0. Test passed.