btc237ftw you are making 2 unrelated and totally wrong points.

1.  If a nuclear war takes place, using all the weapons that the superpowers have, hiding in basements isn't going to do much good as the environment will be poisoned.  Sooner or later you have to breathe and then you will take in poison and die.  As I said, I am no expert and I know the US and Russia are dismantling their arsenals.  But I hadn't known it reached the point that Mutually Assured Destruction no longer applied.  The danger of a nuclear war followed by a nuclear winter is that all life is wiped out.

2. An EMP takes out the electrical infrastructure, not the cables.  It doesn't matter if cables survive when the power stations are disabled and when the routers at the end of the cables are disabled.

If there were a nuclear war of the kind you are thinking, humanity would be reduced to extinction level and we might well be extinct.  There certainly wouldn't be the teams of engineers to run the Internet.  Bitcoin would be worthless.  So would the dollar.  Bullets and tinned tuna would be the new gold.