Well I can tell you one thing for certain. As soon as Quantum Computing becomes a reality, today's sense of encryption or means of securing digital data with passwords will means absolutely nothing. Currently it would take a machine running in parallel with about 1000 zombie machines more than 100 years to crack an AES-256 encrypted password. This is because the best known attack is brute force, which means you literally need to try all possible combinations to break the password. On average you would be able to crack this encryption scheme in 2^255 tries. Which makes its secure, in the sense that it would take and unfeasible amount of time to crack. This same AES-256 encryption scheme could most likely be brute forced in under 10 minutes using 1 quantum machine due to the power it would possess. As a rule of thumb, no encryption scheme will ever be 100% secure due to the nature of physics and mathematics. The best we can do is change or passwords regularly and use things like 2 or 3 step verification methods to add those extra layers of protection. A adversary with a strong will and determination will crack a password in time.