Let me avoid the technical aspects to make things easy for all readers.
So someone said that America's NSA has this great computer(quantum computer) that could easily hack Bitcoin private keys. I really doubt his claim but I know for sure that certain computers like the most powerful Super Computers are within the reach of some of this Intelligence organizations.
Do you think such computers can crack any security codes put in place to make Bitcoin very secure?
I think they can hack the account of a bitcoin user but to hack the system of the bitcoin, I think is it impossible. Although some hacker today can hack many system on a computer but bitcoin is very complex thing to be hack.