This idea also allow to maintain high limits on cash payments to those who still seems to not live without cash.. but to kill 100% -> and I mean really 100% of cash-tax-evasion

THE IDEA IS : put an expiration/validation system on cash bills (maybe only those bigger than 1€ )

:: HOW TO DO IT ::

1) - obviously it would not be convenient to throw away the banknotes so the banknotes are "revalidated" in a database of the state that contains the banknote number and the expiry date.

2) - to revalidate the cash just "photograph" ( maybe in future if this works the bills may have a qr code for a better digitalization ) it with an app for smartphones or specially created tools that follow the same principle of scanning and sending that can also be integrated into special counterfeit banknote detectors or go to the bank with banknotes every MAX 2 years for perform the operation at the counter

3) - the payment operators can equip themselves with a machine that validates the cash (which will probably be like a counterfeit money detector but which moreover read the serial number and validate it (send it to the ministerial database)

4) - expired cash is no longer valid, it can be re-enabled only at a bank by presenting identity documents of those who deposit (or could be worth 40% less than the nominal value creating a kind of "forced tax on the black" ( or read *6 )

5) - during validation (through specific machinery / mobile app / bank counter) the cash is tracked and associated with the validating entity (in this way an operator / private individual will not validate cash for third parties without then declaring it in the balance sheet)

6) .. ( not enough chars, see my comment here below or full : https://pastebin.com/G6WfmxTn )