We will need to design it, but India has a biometrics system (yes big bad privacy issues) called aadhaar which is used for authentication in so many systems. As

We will need to design it, but India has a biometrics system (yes big bad privacy issues) called aadhaar which is used for authentication in so many systems. As long as you can build and secure such a system, and people get used to it, as they are used to Socials now, it can be used to unlock a whole lot of things.