

Safe, yeah. Private, no. If you want to verify whether a user is a real person, you need very personally identifiable information. That’s not ever going to be private.
The best you could do, in theory, is have a government service that takes that PII and gives the user a signed cryptographic certificate they can use to verify their identity. Most people would either lose their private key or have it stolen, so even that system would have problems.
The closest to reality you could do right now is use Apple’s FaceID, and that’s anything but private. Pretty safe though. It’s super illegal and quite hard to steal someone’s face.
Social Democracy is not the same as Socialism. But, I wasn’t following the race, maybe he does want the public to own the means of production.