The problem with that is that it leaks too much information to anyone seeing it — this is bad if it needs to be used with any party you might not trust (or not

The problem with that is that it leaks too much information to anyone seeing it — this is bad if it needs to be used with any party you might not trust (or not trust their security). Serbia (former Yugoslavia) already does something similar since 1970s, and your Unique Citizen Number (JMBG) is derived from your date of birth and county of issuance (usually birth county) and sex at birth, a couple of digits and a single digit checksum. Ideally, government could issue a cryptographically signed ID, so anyone with access to countries' public key can verify authenticity (with revocation mechanism built-in for both individual keys and all keys signed with one government — this is where it gets tricky). Obviously, governments become new CAs, and people in them can provide fakes when they want if they are corrupt, but anyone can easily validate it.