Bitcoin Forum

Thank you very much for this little question.

Yes. Miners are needed to process transactions. However, this is incredibly unlikely - how would every single miner in the world stop working at the same time? Nuclear war? Even then, the Southern hemisphere would possibly escape much of the initial destruction, and - to be honest - the entire World would have much more important things to worry about than sending bitcoins!

We would have to shut down internet for all the world I guess

what if the whole internet was departed into two separated parts?

As I know, the Chinese government may be going to block its domestic internet from other world, to build a so called Chiternet, so that they can control the press\pulic voice.

So the Bitcoin will developed into two independent sysytem, one in China, and one in the freedom world. Then one day, the Bitcoin left in China became the ostrich in Australia??

This. If Bitcoin works, everything should be rather ok, between mid-gray to sparkly white. If Bitcoin doesn't work, something really really bad and more important than any currency is in our focus as a civilization.

You can still run the system just based on transactions without putting them into blocks.
Although things would probably get confusing when people started disagreeing with each other about which transaction came first.

This question is akin to asking "will the whole system stop working if a solar flare erases all computer storage in the world?"
ie neither realistic or useful.

It would only take a single interested party to maintain the connection between the two halves, and it would only be a trickle of data.  I doubt that even China could prevent it.

If there were only one party linking the web in China to the web everywhere else, it would be way too expensive or congested for bitcoin to use. If it were open to general use it would probably get DDOSed and go down.

So send USB sticks with the latest block every now and then ;)

What makes you think this?

Remember, we aren't talking about one node that all 1 billion chinese people are using.  We are talking about a node passing transactions and blocks between the two otherwise partitioned networks.  The traffic just isn't very big.

Exactly, this node wouldn't do anything differently than all nodes are doing now.

Yes, but it'll also be the only route to all the IP addresses not in China, so all of those requests will go through it.

Even if somebody has their own connection (using say a satellite dish) to the external internet, and decides to use it purely for bitcoin (unlikely  ::) ) the government can probably find them easily and remove their connection to the Chinese internet.

Yes, but it still sees the same number of transactions and blocks, which is all of them.

OK, but what about everybody else in China?

I'm not sure you know how a network works.

Each node accepts a message (if it doesn't already have it) from one peer, and offers it to all other peers.  If they also don't have it, they will accept it and repeat, spreading the message far and wide.

In the case of a near-partition, where one single node is the conduit that links both halves of the network, the network still operates normally.  A message from one half will spread normally until it reaches a peer of the conduit node.  The conduit node will then accept it, and pass it to the other half, where it will again, spread normally, until it has saturated the entire network.

Observe that each node, including the conduit, is getting and potentially passing each message.  Message traffic is no greater at the conduit node than at any other.  The conduit node will have slightly greater upload traffic, in both directions.

Also, keep in mind that network traffic is tiny.  The last 20 blocks on the explorer total 367 kB, and were spread over 3.5 hours.  That is a data rate of about 300 bits per second, slow enough that you could have read it out loud.  If traffic expanded by about a million times, it would start to get close to being too much for a 56k modem.

This is exactly my point. If there literally was only one computer connecting China and non-China, then all messages which need to cross from one side of the network to the other would go through that one computer. Unless it was set up correctly to be used purely for bitcoin, it would not only transfer the 300 bits per second of bitcoin, but all the terabytes/second of everybody in China requesting any website not in China. It would go down in an instant.

Even if it were set up to be used purely for bitcoin, it would receive connection requests of everybody in China requested any website not in China, and just refusing those requests would cause it to go down.

But I have to admit I don't know the details of routing protocols. How does this computer announce (falsely) that it doesn't have any routes to non-China? IP? BGP? I don't really know the technical details.

Also, if the Chinese government has a way to figure out where this computer is connecting to the Chinese network, they can cut it off, making it purely part of the non-China internet (even if the computer might physically be located inside China).

Oh, heh.  IP routing doesn't work like that.  You will never find yourself routing IP traffic accidentally.  There was an incident back in the late 80s, before BGP, but it doesn't work like that anymore.

It sounded more implausible with every word I typed, lol. My second criticism/worry still stands.

If a government can prevent bitcoin nodes inside their country's network, then it doesn't really matter if someone is able to get a pirate connection to the real internet, except to the person with the connection.

If all miners shut down, wouldn't the difficulty become very low? Then I could start the world's only miner, and actually have a shot at mining some coins ;D

No because the difficulty only changes every 2,016 blocks. If all miners shut down, nobody would find enough blocks until the next difficulty readjustment.

Then again, if all the miners shut down, I think the lack of new blocks would be the least of our concerns.

So we'd be fine if the miners shut down after the 2,015th block after the previous difficulty adjustment?

No because the next block would have a new difficulty. But that difficulty would be calculated on the timestamps of the previous 2,016 blocks (if they took more than two weeks, difficulty goes down, otherwise it goes up) so the difficulty would still be normal and require roughly as many miners as we have now to keep it going.