[rbjorklin]

The Github page has this to say: "The token should be durable enough to survive on a key chain for years, even after going through the wash." [0] I'd guess covering it all with hot glue would provide sufficient protection.

[0] https://github.com/conorpp/u2f-zero/

[dom0]

Hot snot gets icky with time, rather use a conformal coating; they're available in spray-form as well (e.g. CRC Urethan or Plastik 70). That being said FR4 is a really tough material and it's quite difficult to pry SMD parts off.