Bitcoin Forum

After learning about the 0.7, 0.8 mishap last night, I heard one of the knows-what-he's-talking-about people describe the situation as a fork, but not a "network fork" - both chains were still receiving all of the new transactions and it will all settle out - "be still my children", or something like that.

That got me to thinking.  I can see how we can / will recover from the current situation.  But how would bitcoin recover if it was a true network style fork.

As an example, let's say bitcoin catches on in Iran (but it could be anywhere) and we are now a couple years down the road, with miners both inside and outside the country.  Now, we have seen repressive regimes truly firewall their countries.  They may very well have reason to prevent blockchain content from leaving / entering the country, but blockchain activity within the country would still go on.

This would be a "network fork", right?

What would happen when the floodgates finally opened again and the two sides were allowed to talk to each other - after, say, a year or more of growth.  Wouldn't the shorter block be completely wiped out - instantly?

Just thinking...

If an isolated, smaller group of miners started producing blocks b/c they couldn't connect the rest of the network, every one would realize this.  Those miners would likely shutdown to save power b/c their blockchain will not become the agreed upon chain.

even if many blocks were mined and transmitted, as soon as they re-connect to the mother network, they would have generated many fewer blocks.  clients in the affected region would abandon the shorter chain and download the longer one. 

I'm not sure what would happen to tx's, but all the coins created as block rewards would disappear.  If they were transferred on a dead chain, those transactions too would disappear.

i think thats how it would work.

If you're a miner in someplace where there's a concern your external internet access could be cut off, there's a simple solution.

Use the connect= argument in your bitcoin.conf file, and connect only to peers outside your country's control.

See here:

https://en.bitcoin.it/wiki/Running_Bitcoin#Bitcoin.conf_Configuration_File

If all your peers are external to the country you're in, you'd find out pretty quick.  That's for solo mining, of course.  If you were mining in a pool outside your country, it would just error out.  If you were mining in a pool whose servers were located inside your country, it couldn't hurt to ask them about their peer setup.

The transfers on the block that become orphaned will have to get in to a new block again. They will not disappear.

@BTC Books
The Connect= argument is something I didn't think about.  Anyone who makes it outside the country will be able to quickly propagate their known longer chain within the country - and the problem would be temporarily solved.

But the other answers do confirm my fears that, in one of the places you need bitcoin the most (i.e. in a repressive country) it becomes very dangerous to rely upon bitcoin transactions.  Double spends become real possibilities for someone who can travel or personally access the outside.  As a merchant receiving BTC in this kind of country, I would have very little knowledge and no control over whether my coins might someday just disappear.

So I guess I have to dig deeper into my initial assumptions to know how real this possibility really is.

Is the assumption in the Bitcoin community that governments can't really shut things down effectively enough to cut Bitcoin off (with things like encryption, tor, occasionally walking a USB across the border, etc.)?

It just doesn't sit right with me that there was such intense concern over the (minor and short-lived) fork on Monday.  Especially if governments could effectively force a network fork within their region.  I'm sure many governments couldn't fracture the blockchain without crippling a large part of their own economy at the same time - the internet is just too deeply connected.  But repressive, desperate countries may - and that puts a chink in the "robustness" promise for me.

There are a lot of assumptions about many different possibilities.  And really - just like yesterday's fork - until they happen, who knows?

But I don't see trying to connect to a valid blockchain as much of an issue in the case where a government is behaving as badly as you're concerned about.  I think you'd probably be much busier trying to get out with a whole skin.  In the end though, getting your bitcoin out would be a hell of a lot easier than getting a bunch of gold or silver out.

Forks is also the town where the movie Twilight was filmed.  Don't forget that, too.   
http://twilight.inforks.com

What you are predicting is like the desert island scenario.  The answer to that was:


All this "desert island" would need is a single node with outside connectivity.  The bandwidth requirements are as small as what a dial-up modem provides, with intermittent / period connectivity during each day.  Then that node would then communicate with the local peers on the island.  New blocks would arrive to this node and new transactions would be broadcast out from it.

Of course, the requirement for there to be block confirmations before payments are recognized would be a necessary variation (e.g., no 0/unconfirmed for the anonymous tourists to the desert island).

That is a helpful quantification of the issue.  And the linked post (and its linked posts) completely round out the discussion.  Thanks.