Not sure what they do in the EU, but these seem solveable.
> What if you lose your card?
Each country could keep a log of revoked publishable keys. Countries do more complex things to validate VAT IDs today, so this wouldn't be out of the blue.
> How do you prove your identity to get a replacement? How do you prevent someone from reporting your card as stolen, representing themselves as you, and getting a new card (with a new PIN) issued in your name?
Governments need to solve the same issue with lost passports today. In some cases you can have other people to vouch for you, putting their own identities on the line. In other cases, you use other forms of ID (including immutable things like biometrics). Society has generally made this not a problem, and a new form of ID won't make it worse.
> What if you forget your PIN, how do you reset it?
At the worst, it's treated as a lost card and get a replacement. There are probably ways to make this better but my point is: solveable.
> What if you lose your card?
Each country could keep a log of revoked publishable keys. Countries do more complex things to validate VAT IDs today, so this wouldn't be out of the blue.
> How do you prove your identity to get a replacement? How do you prevent someone from reporting your card as stolen, representing themselves as you, and getting a new card (with a new PIN) issued in your name?
Governments need to solve the same issue with lost passports today. In some cases you can have other people to vouch for you, putting their own identities on the line. In other cases, you use other forms of ID (including immutable things like biometrics). Society has generally made this not a problem, and a new form of ID won't make it worse.
> What if you forget your PIN, how do you reset it?
At the worst, it's treated as a lost card and get a replacement. There are probably ways to make this better but my point is: solveable.