2 ms·
If FHE has a practical internal xor operation, the idea of iterating a key and diversification component/counter, e.g. like a FHE implementation of HOTP or OCRA
by motohagiography 6y ago
If FHE has a practical internal xor operation, the idea of iterating a key and diversification component/counter, e.g. like a FHE implementation of HOTP or OCRA becomes really interesting. Even if it's slow, you could probably stack the slow operations into the initialization/personalization phases.
Security and authN protocols are really just about using crypto to diffuse and distribute risk, so it's conceivable there are use cases where FHE facilitates shifting risk for key security onto the end user, like payment cards, etc.
- lifeisstillgood 6y agoSo, just checking in case I am being dumb, HOTP (like TOTP) works where both parties have shared secret key (common in corporate remote logins). The value here being that I can make my own secret key, and via FHE send the server a "cloaked" key that they will get the right answer without knowing my secret. So apart from the initial key sharing, it's down to me to keep the key safe (as you say, pushing risk into the consumer like debit cards) Feels like it where FIDO goes next.