IBM: We're on the cusp of the Quantum Computing revolution

[drm604]

1. "it can try every conceivable password to access a system within a second"

Only if the system you're trying to access can and will allow it to try every conceivable password in a second. No system (other than possibly another quantum computer, and I'm not sure of that) is fast enough to accept that many attempts that quickly. Even if it could, any properly designed system would lock you out after a handful of failed attempts.

The danger doesn't lie with the ability to guess passwords. The danger is that a quantum computer could, at least in theory, factor large semiprimes in a reasonable amount of time. That could make it possible to crack public-key encryption and, as I understand it, that could put our whole financial system in jeopardy.