That assumes that the universe is both deterministic and reversible. SHA2 is deterministic, but good luck reversing it. Essentially, to work backwards, time, wh

That assumes that the universe is both deterministic and reversible. SHA2 is deterministic, but good luck reversing it. Essentially, to work backwards, time, when going forwards from state A would need to move to some unique state B. Consider two hills with a valley between them. In one universe, I roll a ball down one hill. In the other, I roll it down the opposite hill. In both, the ball ends up in the valley, and the information about which hill the ball rolled down is lost. You could perhaps argue that other effects (me disturbing the air on the hill I walked up) might still imply which hill the ball rolled down, but the question really is if such a scenario could exist, probably in a more simple form.