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 the blockchain technology is too strong to be hacked. There has been previous unsuccessful attempts to hack and that has created much awareness and vigilance against such attempts. I don't think having powerful machines(quantum computer) can easily crack security codes.