> First, retina scanning output hash is deterministic - it is supposed to generate the same result for the same eyeball. So it can't be replaced with random number generation.
His argument is valid, what stops you from replacing the retina scan with a random hash replicating a different person scanning each time and collecting new tokens? What ties the hash to the actual retina other than the device that you can mess with?
Presumably the orbs produce a verifiable type of hash. E.g. whatever output it has is also encrypted with their private key + some salt and you can always check if what a user provides has that.
Would it not just be a matter of time until the orbs are reverse-engineered and you can sign arbitrary input? Especially if this currency were to actually gain significant popularity.
It can be done in following way. Orb can have a baked-in private key (on hardware level). Public keys are stored in the blockchain. Each hash is signed by the private key stored in the orb.
That's orthogonal to the point. Here's the scenario:
1. User has a "fake" biometric A, generated via GAN or [1], that's cheap and easy to produce.
2. Suppose they can present A to any orb device, generating hash(A), which signs hash(A) using its built-in private key as usual.
As long as the user can generate a fake iris biometric scan accepted by an orb, no other part of the system needs to be compromised for this attack to work.
See my original post. It's pretty clear that process of initial distribution of tokens is not open. Volunteers are likely contributing lots of private data to the company to get their hands on orbs.
The orbs are centralized either way. And I personally am less worried about someone having a hash of my eyeball data than my passport and everything else.
His argument is valid, what stops you from replacing the retina scan with a random hash replicating a different person scanning each time and collecting new tokens? What ties the hash to the actual retina other than the device that you can mess with?