InfoCard was actually ahead of its time and surprisingly open considering Microsoft hadn't been slapped down by the antitrust trial yet and chastened.
Thales bought Gemalto, a leading maker of smart cards, SIMs and HSMs, although they had to divest their previous nCipher HSM acquisition due to antitrust concerns.
Whatever the solution ends up being, it will be based on public-key encryption and the governments holding the master keys will almost certainly use HSMs to manage them, and most likely smart cards or some similar hardware security token tech like FIDO U2F. The keys are too sensitive to be help in a general-purpose computing platform because of client security flaws. The EU will in all likelihood insist that the manufacturer is from a EU country and the entire supply chain including manufacturing as well.
Disclaimer: the CEO of Thales is a classmate of mine, but I haven't talked with him in over 2 decades.