A variant on the Internet failure question.

[NotATether]

Do you guys realize that for any internet shutdown to be total, every single server provider in the world has to be segregated in one of the two forks? Otherwise, servers on one server provider can still talk to servers from another provider across the divide. Simply blocking rival search engines and media platforms isn't enough to make a split (not to mention that this would cripple globalization and all internationally operating companies in the process since it makes their revenue models possible - but that's a whole different topic all together).

Governments do not have the power to force all providers in its country to block access to all other providers' IP addresses in another country because it doesn't even know who all the hosting providers are.

Also this would require the chinese/russian part of the internet to block ALL IPs from the major cloud computing services AWS, Azure, and GCP which a significant portion of the world's business relies on for their continued operation. Russian companies in particular cannot survive such a split as many are heavily tied to these services, unlike China.

If you have different servers from both sides being able to talk to each other then you can make paths between bitcoin nodes on them to keep the network in one piece.

And this doesn't even take VPNs and Tor into account - There's absolutely no way you'll be able to split the internet into a perfect half and so VPNs and Tor provide a loophole, or bridge to connect the two sides. The bitcoin network already natively supports the Tor network and is used by a large portion of nodes, and it can provide connectivity in case of emergency situations like this.

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[o_e_l_e_o]

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Even more simply than all that, we aren't even considering any non-internet based methods of syncing blocks. We already have Blockstream Satellite operating globally, meaning any walled off section of the world can still stay up to date even with no internet connection at all.

The scennario described above will almost certainly never happen, but it does provide for an interesting thought experiment.

[NeuroticFish]

Bear in mind, of course, that they are only going to be finding 1-2 blocks an hour on average with this much of the hashrate, so it would only be overturning maybe 1 confirmation rather than 6.

You are right. Just the "1 hour" part was the minimum minimorum. If such a split would happen, I'd expect it to last... years.

Do you guys realize that for any internet shutdown to be total, every single server provider in the world has to be segregated in one of the two forks?

I think that some sort of packet filtering may already do the job. And this is what one or more totalitarian countries may do. Imho any other approach is not feasible.
Of course, human ingenuity can overcome this in some cases, but I wouldn't rely on this as a general rule.
And in this case the "second fork" may be actually not existing at all (i.e., problem solved, bad luck for those behind the firewall)

And this doesn't even take VPNs and Tor into account

If one didn't use VPN or ToR, he may need some time to adjust. And some time is also lost until people understand what's happening so they can react.

[Jet Cash]

You wouldn't need to control all the servers, you would only need control of the pinch points where the traffic leaves the continent. It may be possible to control satellite communications with government legislation.

There is another interesting possibility with parallel chains. If a mechanism was created to transfer coins between chains,and market arbitrage was allowed to stabilise the value, then you would have effectively doubled the quantity of Bitcoin, and the government (bankers?) could monitor and control the movement between blockchains. One obvious mechanism would be for each blockchain to have a wallet for the buying and selling of its coins on the other blockchain. Of course this implies equal demand for both coins. As banks and investment houses increase their ownership of Bitcoin, they may see this as an easy way to increase their Bitcoin wealth.

[BlackHatCoiner]

There is another interesting possibility with parallel chains. If a mechanism was created to transfer coins between chains,and market arbitrage was allowed to stabilise the value, then you would have effectively doubled the quantity of Bitcoin

I don't believe that Bitcoin would ever had parallel chains or two chains that have no connection oversea. If we assume that nodes kept following the same rules, then they'd all follow the chain with the most work. Let's take an example where China's chain is in block 690,000 and Russia in 689,995. (And China has more work than Russia)

An attacker could double-spend a transaction by having it confirmed in the Russia's chain and then by sharing China's work via Satellite or even by calling a Chinese friend. He could tell him the proof of work values; one chain would always have less computational power offered and they could, thus, repeat the process.

The system would collapse and Bitcoin would be worthless.

[NeuroticFish]

The system would collapse and Bitcoin would be worthless.

It won't be parallel chains, it would be forks. So it's more likely that there would be multiple "bitcoins" at different prices, that's all. No other way to prevent double spending if we get to this.
As soon as we'd get to about 50% of hash power gone missing, the devs will have to act fast.

[Jet Cash]

I probably shouldn't have used the phrase "parallel chains", it was a limitation in my concept of the change. Of course, all the parallel chains are the copies run by the existing nodes. The chains would be parallel up until the separation, and that would cause a fork as has been pointed out. The interesting challenge would be to maintain the same value on each fork, and an interchangeability. Failure to do this would mean that one fork would become just another alt like Bitcoin cash.

[DannyHamilton]

If one didn't use VPN or ToR, he may need some time to adjust. And some time is also lost until people understand what's happening so they can react.

It only takes 1 person.  As long as at least one person on each side of the divide finds a way to share blocks to and from the other side of the divide, then blocks will continue to occur at an average rate of 10 minutes, and the chain remains unified and unsplit.  Everyone else can continue to run the way they always have.

If a mechanism was created to transfer coins between chains,and market arbitrage was allowed to stabilise the value, then you would have effectively doubled the quantity of Bitcoin,

Assuming a chain split, coins cannot be transferred between the chains. This is for a variety of reasons, but most importantly because new coins mined will ONLY exist on the chain they are mined on.

Notice that there is no method for sending Bitcoins to a Bitcoin Cash wallet, or vice-versa.

As soon as we'd get to about 50% of hash power gone missing, the devs will have to act fast.

There's no need to monitor hash power.  We are talking about a situation where ALL forms of communication with large population of the world suddenly come to a complete halt.  No radio, no telephone, no internet, no television, no postal mail, no semphore flags, no travel, nothing.  This is going to be something the ENTIRE WORLD is going to be immediately aware of.

The interesting challenge would be to maintain the same value on each fork, and an interchangeability. Failure to do this would mean that one fork would become just another alt like Bitcoin cash.

This isn't possible.  In order for it to happen, the exact same transactions would need to occur on both forks, the exact same hashpower would need to be maintained on both forks, the exact same amount of power would need to be used for having on both forks.

Any variation in the usage of a thing alters it's value.

[Jet Cash]

My idea for the attempted synchronisation would involve a dedicated account on each chain, and this would be a controlled exchange. The credit would be transferred in the exchange, so coins would not move from their blockchain. It would require an equal flow in each direction, and variation in this would create a price imbalance, and an arbitrage opportunity. This is much the same as fiat currency exchanges at the moment.

The extension to this is that each country has its own Bitcoin blockchain, but that wouldn't be done by forking the existing chain. It would also need government support to establish an initial value. I guess this is what is being created at the moment,but unfortunately decentralised Bitcoin type blockchains won't be used. Maybe we need an asic resistant people's Bitcoin to regain an independent currency.

[o_e_l_e_o]

It may be possible to control satellite communications with government legislation.

How? How could a country prevent all incoming radio waves from satellites they do not control short of either attacking the satellites and starting an international war, or encasing the entire country in some sort of anti-radio wave technology?

My idea for the attempted synchronisation would involve a dedicated account on each chain, and this would be a controlled exchange. The credit would be transferred in the exchange, so coins would not move from their blockchain.

But why would anyone want value on the other chain, unless they had some way of accessing it or communicating with someone else who could access it for them? As soon as they can, then there is not an impenetrable wall between the chains and so they can stay in sync.

[DannyHamilton]

It may be possible to control satellite communications with government legislation.

How? How could a country prevent all incoming radio waves from satellites they do not control short of either attacking the satellites and starting an international war, or encasing the entire country in some sort of anti-radio wave technology?

More likely, they would make it illegal for anyone within their own borders to transmit TO the satellite. In this case, they can attack, imprison, kill, etc those dissidents within their borders.  As such, any blocks solved within the country (and any transactions created within the country) would never get out to the rest of the world to join into the rest of the world's blockchain.

Radio signal jamming internally might also be an option, as well as strictly enforcing a ban on any satellite signal receiving equipment.

Are any of these likely to be attempted (let alone succeed)?  Only in Young Adult dystopian-future Sci Fi novels, but apparently, that's the point we've reached in this discussion.

My idea for the attempted synchronisation would involve a dedicated account on each chain, and this would be a controlled exchange. The credit would be transferred in the exchange, so coins would not move from their blockchain.

But why would anyone want value on the other chain, unless they had some way of accessing it or communicating with someone else who could access it for them? As soon as they can, then there is not an impenetrable wall between the chains and so they can stay in sync.

I'm not sure, but I think this is talking about at the end of the novel (or in the sequel?) AFTER the end of the war.  When the world joins back together in peace, and they have to deal with all the ramifications of what happened during the war, including the fact that there are now two separate and functional Bitcoin blockchains each completely valid and supported by those that continued to use Bitcoin throughout the Great War.

[vanessacummings]

This is something that would have come to everyone’s mind but we choose not to talk about it. If something like this ever happens, I am sure that Russia and China will create their own internet.