But wait! Even for this to black market scenario to happen, you still need miners. Again, finding and jailing the miners would be childs play for the authorities, even if any existed that were willing to work at high risk for low monetary return.
How could mining be banned? It is simply using a distributed network of computers to solve a set of math problems.
If bitcoin is banned globally, then by default mining is. If you are mining bitcoins, and bitcoins are illegal..... then the second you collect your reward and use it - you have broken the law. And if the "Ban" is seriously enforced, then they will simply track down the Miners, and pick them off one by one.
I applaud your attempt
(even though amazingly naive and idealistic) that mining is "simply using a distributed network of computers to solve a set of math problems", but my guess is that under the scenario in which all the governments of the world ban bitcoin, that anyone will be fighting a winning Supreme Court battle with that argument. It will look really good etched in the concrete of your jail cell wall though!
Criminal Defense: I am just a guy solving complex math!
You have pretty similar thing with sharing illegal content via torrents (p2p). It's illegal to do so everywhere afaik, but just look how they can fight agains it - they can't, and
too add -
why would they fight bitcoin is the way you are describing ? Just because it's better than any other model out there that they created ? I don't think it will ever happen.
Not 100% sure that I understand your position so I will answer both sides...
If you are saying why would R3CEV/Hyperledger/BigBanks fight Bitcoin becoming THE Global Currency? The reasons are astoundingly numerous. They couldn't control or manipulate it being the primary. Security & Anonymity issues are another couple of big ones.
If you are saying that in the scenario that the OP suggested, that ALL Government banned bitcoin.... Why would they aggressively enforce that ban, well, I am not saying they would. I am saying it is highly possible,a nd there are some supporting reasons..... the biggest of which is terrorism/fear/politics. Assuming the OP's scenario of a global ban, it would most likely be because another cryptocurrency , a FiatCoin, had been chosen and implemented. Why would they want to allow a black market cryptocoin (bitcoin or any other) to be used to anonymously transfer funds in what most likely would be a limited market including cyberterror, terrorism, drug cartels etc. It's sort of a no brainer.