yeah, this is one actually practical use for quantum states. i believe that you can do quantum stuff with electrons as well but for different effects, specifically i have a hypothesis that certain quantum states of electrons (a pair of opposite spin in a tight orbit with each other) can influence the effect of gravity.

i remain extremely skeptical that quantum computers will ever break elliptic curve cryptography however. i'm pretty sure that it will eventually turn out they can't do it without only a small margin less energy and expense as just doing it the old fashioned brute force way, which kinda renders the threat irrelevant.

however, it may well be that with the use of quantum based memory and signals they can leapfrog that whole thing anyway.