This is a very bad idea. It's easy to get enough DNA, covertly. You're constantly shedding DNA-containing bits.

I think the argument would be that it's easy to get a sample of a person's DNA, but you can't fake it when the person authorizing you takes a fresh sample.

Sure, but someone else could pretend that they were you, with your DNA. They'd need to fake the "fresh sample" part, but that's doable.

Of course, they take a hair from your head; and it was exactly the fake hair they had prepared, and then they take a drop of blood from your finger; and its the fake finger you prepared; then they check your iris and its the eye transplantation from the victim just like you prepared.

That's a good point. But I still don't like it.

I mean, there are circumstances where it'd work. But the requirements for verification and chain of custody would limit usefulness, I think.

Yeah, trust companies like Equifax instead.

"real time" PCR and other such techniques could make (will/is) something like this feasible... but you wouldn't need to get pinched or poked.

It could probably extract DNA in real time from your sweat or breath.

But then DNA will become just another identifier, because we'll be able to synthesize it too, and then amplify it again, use it to trick the machine, and so forth.

EDIT: leaving the error, but real time PCR is actually a lab technique. I meant basically super fast sequencing

Synthesize it? You can change your DNA in the future? Like they are looking at the blood going out from your body and they can fake that too? Future is amazing.

Just the application or would you want to get pinched every time you would want to log in? Sounds really painful.

Not to mention changing your DNA if it gets compromised will be difficult.

I think it's actually could be a pretty good system. It's a piece of information that uniquely identifies you and even if it's totally public it doesn't help someone impersonate you. Sure someone could easily produce a sample of your DNA but they couldn't fake a fresh blood sample taken by the person authorizing you.

Cheek swabs are a thing, and the most common venue for collecting DNA.

"Perfect for identical twins!"

They are identical for the purposes of a standard test. The fact that a difference exists doesn't mean you can find it.

This would likely reduce the rate of bone marrow donation.