This is as good as Photon-DSP Authentication
The face of the coin IS its own authentication. The bar coding is tied to a mega mega pixel picture of the surface of the coin with all its pits and scratches.
https://www.amazon.com/stores/author/B00KXD2NNG?ccs_id=4c71321d-f835-41bc-8e00-1b5bb83c5fb9
Inventions by Robert Fenton Gary 