Could such a quantum computer (or perhaps future versions of it with more qubits) crack Bitcoin's encryption? I don't really understand enough about quantum mechanics or cryptography, which is why I'm asking PF people here :P
[Genuine] quantum computers are still under development.
D-Wave Two is most probably not a real 512 qubit quantum computer.
D-Wave One costs $10,000,000.
D-Wave is constructed to solve a specific problem.
Professor Umesh Vazirani [one of the founders of quantum complexity theory] stated – “even if it can be scaled to thousands of qubits, would likely not be more powerful than a cell phone”.
Scientists from ETH Zurich that had access to a 128 qbit D-Wave computer outperformed it by a factor of 15 using regular digital computers.
The SHA-512 in Bitcoin can be replaced/reinforced.
The real strength in Bitcoin is the transactions block chain, distributed over the entire network.
Bitcoin is typically for minor transactions, not millionaire deposits.
If/when a genuine quantum computer is commercial available, you better watch out for your Visa card and bank account – all internet security [https] will be compromised.
The answer is no.
The D-Wave computer (the 512 bit version) does indeed seem to be much faster than a classical computer for very specific problems (mainly optimization), but it is not a "normal" quantum computer and you can't run Shore's algorithm on it. Hence, it can't be used for code breaking (it seems to very good at image recognition, which is why Google is interested).
Note, however, that there mere fact that it actually does seem to work well enough for real applications is quite cool
