The procedure at the USCIS to get my green card was remarkably thorough. The guard manually and visually checked each of my fingertips carefully to ensure I had no fake print overlayed on top of my real print and I had to keep my hands within a small area with a camera on it for the entire process or they would restart everything.
All encryption will eventually be broken therefore what’s the point is a pretty bad security posture. But like no it won’t. Even if you can fake every other metric (good luck with eyes) a fresh blood sample taken by a guard with hypothetical futuristic instant DNA sequencing will never be broken. If your threat model is someone cloning you, the you have bigger problems and they still can’t clone your fingerprints!
You’ve got revocation completely ass-backwards. If someone successfully tricks a biometric system you don’t need to revoke someone’s fingerprint, you revoke the reader! That’s the thing that actually provides all the security.
The point of the guard is that a human has absolutely no trouble determining whether they’re taking a reading of a real hand, scanning a real eyeball, to taking a real blood sample. Maybe in mission impossible movies but you’re really really overstating the resources required to make a convincing hand to someone specifically looking for fakes. Yes social engineering is a problem which is why an autonomous system with the detection quality of a human would be nigh unbeatable.
When a given crypto scheme is broken, you can change to one that isn't. When your physicality is compromised, you can't change to a new body.
If that's the point, the effort is doomed. All biometrics will be able to be reproduced sooner or later. There's no way around that.
So, like all other identifiers, revocation is an important trait. Even if successful reproduction is difficult and rare, it would be utterly devastating to those affected unless there's a way to revoke.
> Perfect: A human guard manually taking a fingerprint reading. Can't be beat because the guard can obviously see that it's not really your hand.
Not at all perfect. Can that human guard really see if you're wearing a fake fingerprint? I doubt it, unless he's closely examining everyone's fingerprints first. And even then...