Theoretically, quantum computers will render all current cryptography insecure. That includes AES, RSA, SHA, SAH256, Blowfish, etc. The underpinnings of SSL, bank security and others.
Frankly, I don't think it will happen in my lifetime.
How can you say it won't happen in your lifetime? Google and NASA are already using quantum computers, aren't they?
Are you referring to the D-Wave? It is far from a general usage computer. Also, very few people have agreed it actually is a quantum computer.
From what I read it is all research and theory at this time. That whole super conductor issues has to be solved first.
There might be some very very small tests that have been done. But, they have a long way to go before there are any practical uses of quantum computing.
But, still my point stands. If a quantom computers start to exist, then pretty much all crypto will have to move to them, not just crypto currency.