Is Voice On EOS Safe To Give Your Biometric Information To?

I don't have an answer to that question but I'll discuss some factors involved. Voice is a social media app on EOS. It's designed to keep bots out and to allow each unique individual to have only one account. That way, you can implement account based voting among other things without the possibility of gaming the system by creating a large number of bot accounts. Voice uses a system that involves the user giving biometic data at registering an account. I haven't tried it but most likely the information is along the lines of fingerprints as many smart phones have fingerprint sensors these days or allowing a face recognition program to take images of your face using a webcam. Something like that.

From what I've understood, Voice is not interested in anybody's personal information or even the biometric data in itself but proof of the fact that any particular account has been created by a unique human and not a bot someone who already has an account. The biometric data itself doesn't even have to be stored on the blockchain or even leave the user's device to be useful for the purposes of identifying that person as someone who does not yet have an account. How is that possible? I'll briefly explain a few cryptographic basic concepts for this to be understandable.

Encryption means using an algorithm to scramble a message into something unintelligible until it is decrypted using the proper decryption key. The purpose of encryption is to render messages unreadable by third parties during transit.

Hashing is a kind of one-way encryption. A hash of a message is the output of a hashing algorithm that took the message as the input. They are often used to check the authenticity of a message because even the tiniest change in the input can cause the output to change a lot. Good hashing algorithms are such that for each output the space of possible candidate inputs is so vast that amassing sufficient computing power to test all possible inputs to find if any of them produces the known output is totally unfeasible.

In theory, I wouldn't be worried about a hash of my biometric data being stored somewhere IF I could be sure that no such computing power ever became available widely enough that would be sufficient to extract the information using a brute force approach. One such candidate technology is large scale quantum computers. Nobody knows when quantum computers of practical size can be built. But EOS is a public blockchain readable by anyone and intended to serve as a permanent and immutable storage of information. There are encryption techniques such as Lamport signatures that cannot be broken by quantum computers. I'd like to know whether the designers of Voice have taken potential developments in computing power into account. Until then, I would not trust EOS to safely store my biometric data.