Is this a federal (US) mandate or a law in any other country?
https://rulesforuse.org/en/about-cbcdg
e.g. for the US dollar:
https://rulesforuse.org/en/currencies/us-dollar
Information on the CDS developed by the CBCDG is sparse:
https://en.wikipedia.org/wiki/Central_Bank_Counterfeit_Deter...
When the work is equal to the knowledge and judgment of the painter, it is a bad sign; and when it surpasses the judgment, it is still worse, as is the case with those who wonder at having succeeded so well. But when the judgment surpasses the work, it is a perfectly good sign ; and the young painter who possesses that rare disposition, will, no doubt, arrive at great perfection. He will produce few works, but they will be such as to fix the admiration of every beholder.
Leonardo da Vinci, "A Treatise on Painting.", p. 225
https://archive.org/details/davincionpainting00leon/page/224...