That's the secret: no one can.

Any data stored anywhere can be exfiltrated through either social engineering, or computer hacking.

Make it illegal to have this data, and if they really want it, then you hit them with jail when it leaks, not fines that can be paid by the board in the form of a golden parachute.

Only those that absolutely need data like this should store it. Like, I dunno, the government? Everyone else can rely on zero knowledge proofs or literally anything else than forever storing a scan of someone's entire fucking identity.