Quick question: can or cannot a powerful actor, like an opressive government compromise bitcoin? For example, run multiple rogue bitcoin full nodes and modifying source code according to their best interest. What is the worst that can happen?
Thanks.
If the government run a billion nodes, far more than the amount of nodes currently running and all those nodes tried to block a payment then what happens? Have a little think about it. Those nodes can't influence the miners and the legitimate nodes. All that would happen is the government nodes would be changing rules but those rules would just be for themselves, the government would end up with an odd alternative bitcoin network that means nothing to the outside world.
The only time they can influence the real bitcoin network is if they forced every bitcoin user to use their version of the code as a node. Of course this is an exponentially harder problem than simply having more mining power than the network.
So the nodes are not an issue. Only having majority control of the miners matters. The government can own 99.999% of all the nodes, but because no real commerce will be done with those nodes it does not matter.