Re: Homomorphic encryption only option
Homomorphic encryption only* allowed for operations to be performed on encrypted data. You still must encrypt it at time of input and decrypt it when you want to use those results, so whilst the attack surface would be reduced**, it is not eliminated. Something, somewhere is going to need to do some math on the key, at which point, whatever facts that can be inferred from these registers come into play.
*this is still pretty mind blowing
** and no doubt increased in other areas