Blockchain split of 4 July 2015

[ElectricMucus]

anti-fragile my ass

[matt4054]

OMG WTF guys? I`m getting scared.

So if i just send now a transaction, then i lose my bitcoins and it doesnt get to the other end?

Also what if i buy now bitcoin with € do i get fake bitcoin if the merchant is on wrong chain?

This could be a serious problem. No FUD intended but seriously, i`m starting to panic/   

Is it just me or is the impact of this non-event severely exaggerated?

[jonald_fyookball]

OMG WTF guys? I`m getting scared.

So if i just send now a transaction, then i lose my bitcoins and it doesnt get to the other end?

Also what if i buy now bitcoin with € do i get fake bitcoin if the merchant is on wrong chain?

This could be a serious problem. No FUD intended but seriously, i`m starting to panic/   

Is it just me or is the impact of this non-event severely exaggerated?

It didn't have much direct impact this time... however, I think there is reason to be concerned.
Imagine if 48% of the hashing power was on the 'wrong' fork instead of 35% or
whatever it was.  You start running into the possibility of a real split network that won't
converge on its own. 

It behooves the community to examine the process by which pools and nodes stay updated.
Honestly, a pool watchdog would be a good thing, to make sure all major pools are operating
on the same codebase.  Or if someone has better ideas, pls share.

[Quickseller]

OMG WTF guys? I`m getting scared.

So if i just send now a transaction, then i lose my bitcoins and it doesnt get to the other end?

Also what if i buy now bitcoin with € do i get fake bitcoin if the merchant is on wrong chain?

This could be a serious problem. No FUD intended but seriously, i`m starting to panic/   

Is it just me or is the impact of this non-event severely exaggerated?

It didn't have much direct impact this time... however, I think there is reason to be concerned.
Imagine if 48% of the hashing power was on the 'wrong' fork instead of 35% or
whatever it was.  You start running into the possibility of a real split network that won't
converge on its own. 

It behooves the community to examine the process by which pools and nodes stay updated.
Honestly, a pool watchdog would be a good thing, to make sure all major pools are operating
on the same codebase.  Or if someone has better ideas, pls share.

I believe that more then 50% of the network was actually mining on the invalid chain for some time. Regardless of how long it would become, it would never be valid.

This is why people shouldn't have relied on any transaction as being confirmed except those that were showing as confirmed by something that got its info from Bitcoin core.

[Brangdon]

Can you explain what happened to transactions that were recorded in the unintentional hard fork, which failed?

Invalid, went back to original address.

Won't most transactions have been propagated onto both sides of the fork? If that happens, the same transaction would get confirmed on both forks and it wouldn't matter to it which fork won. A double-spend attempt could mess this up, but if the sender is honest, the fork shouldn't matter.

[Bitcoin_BOy$]

Hello when should this be resolved and even can it e resolved ?? I hope no ones loose his trust in Bitcoin and leave it just like
that !

Bitcoin Boy.

[Quickseller]

it would never be valid.

This is why people shouldn't have relied on any transaction as being confirmed except those that were showing as confirmed by something that got its info from Bitcoin core.

I know where you're coming from but the bold is untrue. In theory and practice the longest blockchain becomes dominant.

Since most of the world's nodes and miners use the newest Bitcoin Core there was no problem this time, but if China decided to fire up a bunch of miners using the old protocol then Bitcoin Core users would've been the ones on the wrong chain. This is one of the inherent dangers of forks and why they need to be used as little as possible.

Pretty remarkable our community was almost entirely unaware of this fork, I guess considering the XT backlash the devs didn't want to make it well known publicly until it was already done.

No you are incorrect on two fronts.

I could (somewhat) easily create a blockchain that is 400,000 blocks long (roughy 37,000 blocks longer then the current blockchain) however in order for me to do this I would need to  adjust the timestamps of my found blocks so that the current difficulty would be significantly lower then it is today. This would result in a longer blockchain, but one with less total work then the current blockchain. The chain with the greatest total work is the valid Bitcoin blockchain - this is usually going to also be the longest one, however in my example it would not be.

If miners are mining invalid blocks, then they would be mining on an alt coin's blockchain, and it would not be Bitcoin's blockchain....if this altcoin would have any value would be a separate question.

[jonald_fyookball]

it would never be valid.

This is why people shouldn't have relied on any transaction as being confirmed except those that were showing as confirmed by something that got its info from Bitcoin core.

I know where you're coming from but the bold is untrue. In theory and practice the longest blockchain becomes dominant.

Since most of the world's nodes and miners use the newest Bitcoin Core there was no problem this time, but if China decided to fire up a bunch of miners using the old protocol then Bitcoin Core users would've been the ones on the wrong chain. This is one of the inherent dangers of forks and why they need to be used as little as possible.

Pretty remarkable our community was almost entirely unaware of this fork, I guess considering the XT backlash the devs didn't want to make it well known publicly until it was already done.

No you are incorrect on two fronts.

I could (somewhat) easily create a blockchain that is 400,000 blocks long (roughy 37,000 blocks longer then the current blockchain) however in order for me to do this I would need to  adjust the timestamps of my found blocks so that the current difficulty would be significantly lower then it is today. This would result in a longer blockchain, but one with less total work then the current blockchain. The chain with the greatest total work is the valid Bitcoin blockchain - this is usually going to also be the longest one, however in my example it would not be.

If miners are mining invalid blocks, then they would be mining on an alt coin's blockchain, and it would not be Bitcoin's blockchain....if this altcoin would have any value would be a separate question.

I think you are right from the point of the view that assuming the miners EVENTUALLY all switch to the 'correct' version, then THAT will become the longest chain.
However, I think turtlehurricane could be correct in the situation where a long chain is built that ignores, say a certain BIP, and then the community decides
to throw that out for now and just keep mining on the main chain that has been built.  Either way, its going to boil down to the consensus of the community
and which version they ultimately choose.  However, it will be damaging to Bitcoin if at any point there is a long reorg.

 

[Xialla]

I just checked the blockchain (because again waiting dozens of minutes for confirmation) and this is related, right?

[ShamrockHannah]

My wallet is with blockchain.Info. if I am expecting an incoming transaction does this still apply?

Are you talking about certain types of transactions from unknown sources? 

[JorgeStolfi]

As far as I understand, the incident had some consequences:

* several miners lost the rewards that they mined (at least 6 blocks, maybe more).
* there was a signficant risk of double-spends, since many ciients were watching the bad chain.
* at least one transaction (the one that triggered the fork) was undone after >6 confirms.
* a warning was broadcast telling everybody to wait for 30 confirmations (5 hours).

The incident was not as bad as it could have been because Greg Maxwell and other ore devs were carefully watching the blockchain as the BIP66  triggered the switch from version v2 to version v3 of the protocol, and they immediately spotted the fork.  They soon contacted the mining pools that were mining on the wrong chain.

The fork was started by miner BTCNuggets, that was still running v2 and issued a block N with a transaction that was invalid under version v3.  Miner F2Pool, that was already running v3, saw that block and successfully mined another block N+1 on top of it, not realizing that N was invalid.  Other v3 miners like AntPool added N+2, N+3, etc. on top of F2Pool's block N+1.  Meanwhile some v3 miners did not see the block N issued by BTCNuggets, or noticed that it was invalid under v3 rules and rejected it; so they created their own block N and kept mining that branch.  Until the miners were alerted, the bad branch was longer, so it was accepted by all v2 clients and maybe by v3 clients that did not check all blocks.

Blame is being thrown at the miners, especially F2Pool for mining block N+1 on top of a block N that was produced by a v2 miner, without checking the validity of that block.  The blame may be partly deserved if F2Pool got the block directly from BRCNuggets or from any intermediate relay node still running v2.

However, methinks that the blame should fall on the developers.  After the BIP66 change went into effect, every v3 player (client, node, or miner) should have dropped all links to other v2 players.  Letting v2 and v3 players communicate was begging for this accident to happen.

If F2pool got that block through an intermediate v3 node, the blame should fall on that node.

Miners should not be required to validate the blocks that they receive.  It is their right to decide whether to validate them, or to trust that the sender did so.  Note that the miner that started mining block N+3 on top of N+2 would have had to check also blocks N+1 and N to discover that N+2 was invalid.

Was the incident serious? Suppose that a trash basket caught fire in a gunpowder factory, but it was quickly put out.  was that incident serious?

[Searing]

this may have already been posted these links (op feel free to remove this post if you wish)


https://bitcoin.org/en/alert/2015-07-04-spv-mining


https://en.bitcoin.it/wiki/Comparison_of_mining_pools#SPV_Mining_.2F_Old_Bitcoin_Core



hope it helps ...again if a repeat of previous info feel free to move/delete or whatever

[mark coins]

Is this going to be a major problem ? are blockchain.info wallets safe in the moment? thanks a lot

[Jeremycoin]

Is this going to be a major problem ? are blockchain.info wallets safe in the moment? thanks a lot

I think... this is just for Bitcoin core, as written on the News above

[STT]

So it is not just F2Pool, but also AntPool.
Considering that they have roughly 36% of total network hashrate

36% is too centralised, seems like its a problem even when not apparent that BTC has become too much about bigger is better.  Will it converge with traditional banking on the same basis, maybe its meant to be
Its a mistake to me, if you want to represent capitalism then the capital value and/or means of production should be within the population ideally

[Superhitech]

Are blockchain.info web wallets running Bitcoin Core 0.9.5 and later? Just want to know if I should wait for 30 confirmations.

Is this going to be a major problem ? are blockchain.info wallets safe in the moment? thanks a lot

I think... this is just for Bitcoin core, as written on the News above

No, this issue concerns web wallets too.

[tss]

Hi, guys
I'v just registered on this forum. I just wondering...... Does anybody have any info about this Social Community http://mmmglobal.org/ Huh I've just joined and i see that they are based on Bitcoin. They operates with this currency. Any advise??? looks interesting.....

Their FB page https://www.facebook.com/mmmglobal.org

looks like a ponzi made to look like multi level marketing pretending to facilitate person to person money transfer.  im skeptical.  also your post is off topic here and may be spammy but i will reply if it stops you from losing any money.

[Colonel Crouton]

How do we know if electrum and mycelium servers have been updated?

[Hazir]

How do we know if electrum and mycelium servers have been updated?

I imagine we don't know nothing about their servers status. Unless wallets providers will tell us directly that the crisis is averted. That is the problem with the online wallets or like in this case simplified validation wallets, if you don't have copy of blockchain on your machine, things like that could happen and you can't do anything about it. Power in the hands of wallet provider.

[jorgelugra]

Are blockchain.info web wallets running Bitcoin Core 0.9.5 and later? Just want to know if I should wait for 30 confirmations.

Is this going to be a major problem ? are blockchain.info wallets safe in the moment? thanks a lot

I think... this is just for Bitcoin core, as written on the News above

No, this issue concerns web wallets too.

but its affect only the transactions incoming from a user with bitcoin core? or between webwallets too? thank u