In the EU, most states have eID systems. The German system is as follows: You've got a central agency, responsible for IDs, paperwork and currency, with a root

In the EU, most states have eID systems. The German system is as follows: You've got a central agency, responsible for IDs, paperwork and currency, with a root key in an HSM. From this key, intermediate certificates are generated for each ID production plant. This HSM is kept offline in the vault that also keeps the mint masters for coin and currency production. The ID production plants then sign IDs with their intermediate key, also kept in an HSM, and tack their own certificate on. The ID now has an X.509 certificate, or rather multiple ones, with a certificate chain going back to the root certificate of the agency. Now if you send a correctly signed request via NFC to the ID, the ID will generate a response in its own HSM, and return a signed response with the whole certificate chain. Such a request can be "given the following date, is the owner of this ID above 16?" (18, 21 are also available). The request can also be "what is the full personal data for this person?" To send such a request, the request also needs to be signed, also with a certificate chain going back to the same root CA. The agency provides certificates with different features enabled or disabled to different users. e.g. a bar can get one that allows them to query IDs for "are you 18 today?" with a certain limit of how many requests per ID they can make per day (the ID verifies that) to avoid brute forcing the actual birthday. This is for example used in fully automated cash-operated cigarette dispensers. You can also get a certificate that allows you to request all ID data, but is restricted to your own ID.