It’s not because they are 3d printed. He was distributing them at school! That is the problem.

If he were to file down toothbrushes and do the same he would still be arrested and his files confiscated.

Wow, that is absolutely mind-blowing. I never expected it to work with such complex designs! Mind sharing some tips or examples of how you accomplished this? I’m really curious about the notes around the ring

Have you seen the film Gattaca? It somewhat explores the theme of DNA as identifier — as well as some interesting associated themes.

The hashing idea works fine imo. However, depending on how advanced or "primitive* the technology would be, it could be pretty trivial to impersonate another person if the only id used is the DNA sequence. A sample of tissue is not dead, and it’s — I don’t want to say trivial but — not that hard to culture it and keep the cells alive.

With our current tech it’s possible to build layers of lab grown skin from the cells of a patient for transplants.

Of course, this may not be a problem for world building. It could be an element intrinsic in it. After all people do steal identities. Or the tech could go deeper and use more information on the individual: DNA, the microbiote, neural patterns, blood vessel, fingerprints, all together.

I think in the end depends also on the tone of the fiction.