Blockchain split of 4 July 2015

[Pony789]

According to https://getaddr.bitnodes.io/nodes/, only 62% of full nodes are using bitcoin core 0.10.0, 0.10.1 and 0.10.2. Hopefully the alert message will make the remaining users to upgrade.

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[zvs]

So many people are going to get scammed tonight with fake transactions.

from what?  all those 1 transaction (the 25btc) blocks?

nobody is going to get scammed with fake transactions, it's obv not intentional.. if it was, they'd be including a lot of their (own) transactions, instead they are including zero

also, re: blockchain has 'thousands of orphan blocks a day', huh?    more like 1 or 2 on average

ed: the only 'scamming' from transactions that could possible happen were with the original f'cked up block @ https://blockchain.info/block/0000000000000000009cc829aa25b40b2cd4eb83dd498c12ad0d26d90c439d99

[scarsbergholden]

whats the deal now in days everyone is calling about forks like this wasn't happening before, why are miners so hard headed when it comes to an update.

[BitUsher]

According to https://getaddr.bitnodes.io/nodes/, only 62% of full nodes are using bitcoin core 0.10.0, 0.10.1 and 0.10.2. Hopefully the alert message will make the remaining users to upgrade.

Except most are using SPV wallets and wont see the alert message.

BTC Nuggets (the trigger in this case) still has 2.2Ph/s and could start this fork again with F2Pool picking up the wrong block and not validating.

ed: the only 'scamming' from transactions that could possible happen were with the original f'cked up block @ https://blockchain.info/block/0000000000000000009cc829aa25b40b2cd4eb83dd498c12ad0d26d90c439d99

It is doubtful that a scammer could have reacted quick enough but during the fork double spending could have occurred, especially with SPV wallets for any transactions spent in BTC Nuggets block that triggered this.

[gmaxwell]

from what?  all those 1 transaction (the 25btc) blocks?

nobody is going to get scammed with fake transactions, it's obv not intentional.. if it was, they'd be including a lot of their (own) transactions, instead they are including zero

also, re: blockchain has 'thousands of orphan blocks a day', huh?    more like 1 or 2 on average

ed: the only 'scamming' from transactions that could possible happen were with the original f'cked up block @ https://blockchain.info/block/0000000000000000009cc829aa25b40b2cd4eb83dd498c12ad0d26d90c439d99

There was about 4% of the hashrate remaining mining old invalid blocks; these SPV miners would extend them-- effectively boosting the invalid-block mining portion of the hashrate to 50% the moment one of those 4% miners produced an invalid block.

Miners that do not verify, even if they don't include transactions, are a huge amplifier on anyone who mines an invalid or malicious block for whatever reason; and are obviously a grave risk to the system.

More of these forks may still happen-- if these large hashrate miners leave the SPV mining code in place, there still is a few percent mining invalid blocks--- I know for the deployment of the P2SH softfork "50 BTC" continued mining invalid blocks for roughly a month.

[BitUsher]

There was about 4% of the hashrate remaining mining old invalid blocks; these SPV miners would extend them-- effectively boosting the invalid-block mining portion of the hashrate to 50% the moment one of those 4% miners produced an invalid block.

Miners that do not verify, even if they don't include transactions, are a huge amplifier on anyone who mines an invalid or malicious block for whatever reason; and are obviously a grave risk to the system.

More of these forks may still happen-- if these large hashrate miners leave the SPV mining code in place, there still is a few percent mining invalid blocks--- I know for the deployment of the P2SH softfork "50 BTC" continued mining invalid blocks for roughly a month.

My concerns exactly and stated more elegantly than I could have. Perhaps there needs to be a change to the protocol to prevent this practice?

[gmaxwell]

My concerns exactly and stated more elegantly than I could have. Perhaps there needs to be a change to the protocol to prevent this practice?

It's possible to do, prior proposals were dismissed as paranoia. I expect that even the evidence now won't be enough since this expirenced will be discounted as "sure, they were doing that before, but they won't do it again".

And now, you know why chinese pools thought they could survive with 8MB blocks.  Ultimately any proposal to inhibit SPV mining is going to interact in politically complex ways with the block size discussion.

[Mikestang]

Someone just used the alert key.

"Your node software is out of date and may accept an invalid blockchain fork. Do not trust confirmations"

I have 0.10.1, how can that be right

Latest version is 0.10.2. I don't know if that has anything to do with it or not.

I'm guessing its a blanket statement for all old versions, even though 0.10.0 is technically safe

I'm using 0.10.2 and still got the message, it's not a version specific announcement.

[gmaxwell]

I'm using 0.10.2 and still got the message, it's not a version specific announcement.

The message was briefly up for 0.10.2 because 0.10 had failed to increment the protocol version and I failed to account for that. The there are two alerts which are active right now covering everything prior to 0.9 plus the specific subversion strings for 0.9.0-0.9.5.

[Panthers52]

The correct fork now gets to block 363737 and the problem is solved for now. But if another v2 block is created while Antpool and F2Pool failing to reject it, we could have another fork then.

so it was a 6 block orphan chain

I did notice that I was waiting for over an hour for a 2 BTC transaction to get confirmed from TC that took ~5 blocks to get confirmed then all of a sudden I saw that it had 8 confirmations (this may have been 3 confirmations later, so it got confirmed on the first block of the longest chain but not the other).

I also noticed that f2pool was mining an unusually large number of 1 tx blocks (only the coinbase tx).....this is obviously speculation, but maybe they were trying to do something malicious.

IMO this is very interesting. I don't think I have been around since we have seen a reorg of this magnitude. 

[Amph]

this one of the reason why bitcoin is not accepted everywhere, people feel unsecure with all that shitty fork that can happen..randomly

Someone just used the alert key.

"Your node software is out of date and may accept an invalid blockchain fork. Do not trust confirmations"

I have 0.10.1, how can that be right

Latest version is 0.10.2. I don't know if that has anything to do with it or not.

well i'm not getting any warning with the last version

also rc1 is not even a final a complete version

[turvarya]

Can someone explain me like i am five. Thanks.

How I understand it:
There is a fork, because some Chinese miners are using an old version. If you use a newer version of Bitcoin Core, it just ignores the invalid fork: No problem there.
But there doesn't seem to be any info about SPV(e.g. Smartphone) wallets.
A fork means, that when you see a transaction confirmed on the invalid chain, it doesn't mean it is confirmed on the valid chain.
But: Nobody can steal your Bitcoin, it is just about, if you can trust, if a transaction is really confirmed.

[Amitabh S]

What about Bitcoinj. I am using version 0.11-SNAPSHOT. Which fork will this follow? Any help appreciated.

[LiteCoinGuy]

we are doomed.  
---


If you're using Bitcoin Core 0.10.0 or newer you are fine!

The majority of hashing power is mining an invalid chain - it's not going to "win" - they're just wasting their effort.

by the way, the problem is already solved

[RappelzReborn]

What the hell does that means ?
How it's possible to make fake transaction , isn't that only possible when you do 51% attack or whatever it's name is  . I guess I'am safe since I'am using the latest version of Bitcoin core however knowing more about this would be nice .

[turvarya]

What about bitcoinj. I am using version 0.11-SNAPSHOT.

As far as I know, bitcoinj is just a java library. The problem described here is, if the blockchain you have downloaded is valid. So, which blockchain are you using? On your PC or an external node?

[johoe]

Can someone explain me like i am five. Thanks.

ELI5 is difficult .  I try for a higher age...

The developers designed a soft fork BIP66 that does not allow some malformed bitcoin transaction (that have a strange signature that may not be accepted by newer versions of openssl).  To make sure that there is only minimal forking, they had some rules accompanied with the fork.

• Miners vote for the fork by setting version 3 in the block header.
• Only when 75 % of the miners vote, the change has any effect at all
• When 95 % of the miners vote, the new client ignores all miners voting 2 and orphans them off.

The latter should have produced a few orphans for the 5 % that didn't update.  However, it looks like f2pool and antpool just voted by setting version 3 but did not implement the rules of the fork, at least not the last one.   They built a fork on top of a block from a miner that didn't update.  Since they have a lot of hashing power they managed to produce a longer fork that was alive for some time before being overtaken by the miners implementing the soft fork correctly.  The effect is that we may see transactions with 6 confirmations that are later double spend.  Also f2pool will loose a lot of blocks since they are orphaned later.

If you have a full node that is updated, you have nothing to worry.  It will just ignore the invalid forks.   If you have a SPV client, it will trust the miners to not do something stupid like this and thus it may be on the wrong side of a fork.  There is a small chance that you see a transaction with a few confirmations that doesn't make it to the 0.10.x chain.

[coinmaster222]

Whats going to happen with coins merge mining with Bitcoin the likes of Unobtanium ?

[The Bitcoin Co-op]

I love how the problem was essentially fixed by the time I found this thread. The tech community is so efficient

[RustyNomad]

Thanks for the early warning on this.

Making use of a 'light' client and was going to send off a couple of transactions (+-14) today.

All on hold for now.