Bogosort

So as I understand it, quantum computers solve all NP problems in polynomial time. This means all encryption based on the distinction between P and NP, RSA being the most prominent, will be rendered useless.

My question is, are all public-key private-key algorithms rendered invalid? Could there possibly exists some algorithm that exploits the separation between, say, NP and PSPACE?

>>1
A huge misconception about quantum computers is that quantum == exponential computing power. As six alluded to, this is the mainstream hollywood perception. I suggest you youtube some googletechtalk videos about this matter, as I am not an expertise, so I cannot give you a full answer.