Cryptographic replacement for social security numbers

That was my thought initially as well, but SSNs are basically a national ID already, no? PKI or blockchain could actually provide citizens with more control over their identification than they have now.

Of course, I don’t expect the government’s implementation to favor the citizen so much… but hypothetically it could be an improvement.

Yes and no. It was imposed as such by business, not the government. The government never intended for it to be a national ID system.

Estonian ID card example - mandatory document for regular identification, travel document, online identification + digital signature (state and business services built on these). Private key never leaves the chip on card, but as recently discovered vulnerability in chip shows, you have to be prepared for flying brown stuff.
Security is a process.

Issue with crypto device or any other such thing is people are fucking stupid so the help desk costs are going to be fucking crazy.

Pretty interesting that Germany doesn’t have ssns in the traditional sense, did not know that.