The exactly implementation doesn't seem clear, but looks to my uneducated eye like this is still an oracle, but one that could be replicated rather than requiri

The exactly implementation doesn't seem clear, but looks to my uneducated eye like this is still an oracle, but one that could be replicated rather than requiring key escrow with an intermediate knowing the keys. I'd assume that you could add salt & pepper (as with password generators) to create new keys... but then you would still have to pass those to the oracle (e.g. using the oracle's public key, which you could reasonably know) and trust the oracle to generate them correctly. Like password generators you could have many public keys (eg one for each recipient's public key and an advertised pepper that increments with each message) from your single biometric or even including adress, time, or place. I just don't see how any oracle that you don't control access to isn't susceptible to compromise. I also don't see how the biometric is better than a memorized public key (or salt) other than you can't lose it, since spoofing the biometric will still be possible. Correct me if I'm off base here.