Just wait until these fancy "smart" coffee cups with built-in nano-labs become ubiquitous.

If we have nano-labs then we can also have nano-obfuscation-labs to protect our privacy - randomly mutate or CRISPR any DNA we shed

Before that happens, I'm guessing that full DNA sequencing at birth will be a legal requirement. Like footprints are now.

Holly... You're right. This will happen. To an over-arching state this is the ultimate modus.

  INSERT INTO Citizen(dob,ssn)
  VALUES 2030-10-28, sha(atgcaatgcatcgc..)

hashing (sha) is not very appropriate since you're not likely to ever reproduce exactly the same base pair sequence for the same person.

What could you do to a million or a billion people that would make life a nightmare for them if their biometric data was stolen en masse?

My concern is not what can be done today, but rather in 15 years.

Discriminate against them based on medical conditions, persecute them based on "impurities" (think Hitler & Jews or China & Uyghurs), make them targets of fishing expeditions for unsolved crimes, etc.