Blockchain split of 4 July 2015

[Quantus]

Every one calm the fuck down. The problem is not fixed but right now its not a problem.

Here are the events leading up to this.

This is what happened; large mining pools in china found out many months/years ago that they could make more money if they didn't wast any time adding transactions to the blocks they mined. You see adding transactions to blocks takes extra time, time they could have been mining. This allowed them to broadcast their found blocks just a little bit faster. Giving them a slight 1% edge over other miners the same size. But then to save even more time they stopped checking the authenticity of blocks coming in from other miners they felt were trusted.

Now do you remember the whole Bitcoin transaction malleability scare? The one Mount' Gox said caused them to lose all there bitcoins? That event was fixed with a patch but this patch would
only be implemented if 75% of the network agreed to it. Tonight one of the mining farms in china got a bad block that didn't meet the requirements in that patch but broadcast that block saying that it did.  Other Chines mining farms took the block without checking to see it was in fact au8thentic and started building/mining with it/off it/on top of it... Causing a very large orphaned chain.  

Could it happen again? yes unless something changes. It fixed itself tonight but in the future with fewer and fewer full nodes around the world and larger and larger blocks this will only get worse. The larger the blocks the slower the network.

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[AleCrypt0]

So, after all this discussion, are the SPV wallets (i.e. MultiBit) safe for now?

[Jeremycoin]

So, we have to wait 30 confirmations to make sure that it's a real transaction?

Just make sure you're using version 0.10.x. Although you should wait a day or two just to be sure.

No, no, no, I'm  not using Bitcoin core. I'm using MultiBit
I just curious about this issue  

[turvarya]

[snip]
Now do you remember the whole Bitcoin transaction malleability scare? The one Mount' Gox said caused them to lose all there bitcoins?
[/snip]

You obviously don't have any idea, what you are talking about. Mt. Gox didn't lose all their Bitcoin because of transaction malleability.

[Quantus]

[snip]
Now do you remember the whole Bitcoin transaction malleability scare? The one Mount' Gox said caused them to lose all there bitcoins?
[/snip]

You obviously don't have any idea, what you are talking about. Mt. Gox didn't lose all their Bitcoin because of transaction malleability.

never said they did

[AleCrypt0]

Anyone on SPV wallet question?

ARE SPV wallets (i.e. Multibit) safe?

[Quantus]

Anyone on SPV wallet question?

ARE SPV wallets (i.e. Multibit) safe?

From this day forward I would say all web based wallets and smart phone wallets are NOT safe.

[rich93]

I have skimmed through all the posts in tis thread so far and cannot find much information to help those using multibit wallets. The two posts below are all I could find.

If I start my multibit wallet will it corrupt it if it connects to a node mining invalid blocks?

Will I have to download all the headers again if it gets corrupted?

Most normal Bitcoin users will be using light weight wallets like multibit, not Bitcoin core, so it's important we get some knowledgeable advice posted for light weight wallet users.

...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.

Another update from Peter Todd:

"The majority of hashing power is now mining only valid blocks. However, SPV wallets are still vulnerable as they do no validation, and ~4% or so of hashing power is still mining invalid blocks. Don't trust txs in SPV wallets w/o >= 2 confirmations right now."

FYI-- no alert message with 0.10.2 now that I upgraded to test this node.

[trasla]

Anyone on SPV wallet question?

ARE SPV wallets (i.e. Multibit) safe?

From this day forward I would say all web based wallets and smart phone wallets are NOT safe.

Unless, of course, the smartphone wallet is not a spv wallet.
All of myceliums server run updated bitcoin core versions

[Quantus]

If your running any web based wallet I would not trust any incoming transactions with less then 20 confirmations. Because they could be orphaned by the network. Chines farms are spitting out a lot of trash these days in the hope they will make more money. They don't have the bandwidth to send out even 1mb blocks.

[favdesu]

I have skimmed through all the posts in tis thread so far and cannot find much information to help those using multibit wallets. The two posts below are all I could find.

If I start my multibit wallet will it corrupt it if it connects to a node mining invalid blocks?

Will I have to download all the headers again if it gets corrupted?

Most normal Bitcoin users will be using light weight wallets like multibit, not Bitcoin core, so it's important we get some knowledgeable advice posted for light weight wallet users.

...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.

Another update from Peter Todd:

"The majority of hashing power is now mining only valid blocks. However, SPV wallets are still vulnerable as they do no validation, and ~4% or so of hashing power is still mining invalid blocks. Don't trust txs in SPV wallets w/o >= 2 confirmations right now."

FYI-- no alert message with 0.10.2 now that I upgraded to test this node.

Thanks for the updates informations.

what are SPV wallets? multibit and other light desktop wallets? what about blockchain.info and other online services?

[SISAR]

Anyone on SPV wallet question?

ARE SPV wallets (i.e. Multibit) safe?

Using anything other than official Bitcoin-Qt wallet (full node) is playing with fire. For the sake of saving 40GB of HDD space and to have a bit faster syncing you have massively increased a chance for all sort of troubles and you are actualy not contributing to network at all, just draining resources off of it and using up others' connection slots. As far as I know, SPV wallets are not relaying transactions or blocks, they are just like people on Torrent who download stuff but not share anything.

[Quantus]

even blockchain.info didn't detect these were bad blocks. You can't even trust them!

[redsn0w]

even blockchain.info didn't detect these were bad blocks. You can't even trust them!

You should trust only 'yourself' and build/run your bitcoin client with the complete blockchain (and after compare the data).

[Meuh6879]

so two chinese pools went unintentionally rogue and forked bitcoin. however, they made a rollback and fixed the problem, does that summarize the issue?

 No.


They don't have upgraded our server for the BIP66 ...

[rich93]

Anyone on SPV wallet question?

ARE SPV wallets (i.e. Multibit) safe?

Using anything other than official Bitcoin-Qt wallet (full node) is playing with fire. For the sake of saving 40GB of HDD space and to have a bit faster syncing you have massively increased a chance for all sort of troubles and you are actualy not contributing to network at all, just draining resources off of it and using up others' connection slots. As far as I know, SPV wallets are not relaying transactions or blocks, they are just like people on Torrent who download stuff but not share anything.

SPV wallets were Satoshi's idea. He knew they would be needed by people with low spec computers and metered internet connections. People have complained the Bitcoin core wallet can take a week to sync on a low power computer with a slow connection. They say if anything goes wrong whole it's syncing and the database gets corrupted you have to start the whole process again. My computer is too low power and has too little free memory to consider using the Bitcoin core wallet.

Not everyone has the choice to use the Bitcoin core wallet, some people have no option but to use SPV wallets.

[SISAR]

Anyone on SPV wallet question?

ARE SPV wallets (i.e. Multibit) safe?

Using anything other than official Bitcoin-Qt wallet (full node) is playing with fire. For the sake of saving 40GB of HDD space and to have a bit faster syncing you have massively increased a chance for all sort of troubles and you are actualy not contributing to network at all, just draining resources off of it and using up others' connection slots. As far as I know, SPV wallets are not relaying transactions or blocks, they are just like people on Torrent who download stuff but not share anything.

SPV wallets were Satoshi's idea. He knew they would be needed by people with low spec computers and metered internet connections. People have complained the Bitcoin core wallet can take a week to sync on a low power computer with a slow connection. They say if anything goes wrong whole it's syncing and the database gets corrupted you have to start the whole process again. My computer is too low power and has too little free memory to consider using the Bitcoin core wallet.

Not everyone has the choice to use the Bitcoin core wallet, some people have no option but to use SPV wallets.

"Here I have 100,000 USD and I'll put them at insecure and problematic bank because I have no money for better one".  

[Quantus]

Anyone on SPV wallet question?

ARE SPV wallets (i.e. Multibit) safe?

Using anything other than official Bitcoin-Qt wallet (full node) is playing with fire. For the sake of saving 40GB of HDD space and to have a bit faster syncing you have massively increased a chance for all sort of troubles and you are actualy not contributing to network at all, just draining resources off of it and using up others' connection slots. As far as I know, SPV wallets are not relaying transactions or blocks, they are just like people on Torrent who download stuff but not share anything.

SPV wallets were Satoshi's idea. He knew they would be needed by people with low spec computers and metered internet connections. People have complained the Bitcoin core wallet can take a week to sync on a low power computer with a slow connection. They say if anything goes wrong whole it's syncing and the database gets corrupted you have to start the whole process again. My computer is too low power and has too little free memory to consider using the Bitcoin core wallet.

Not everyone has the choice to use the Bitcoin core wallet, some people have no option but to use SPV wallets.

With any luck the chinese miners will start to properly authenticate incoming blocks before they start to mine on them.  

[favdesu]

Anyone on SPV wallet question?

ARE SPV wallets (i.e. Multibit) safe?

Using anything other than official Bitcoin-Qt wallet (full node) is playing with fire. For the sake of saving 40GB of HDD space and to have a bit faster syncing you have massively increased a chance for all sort of troubles and you are actualy not contributing to network at all, just draining resources off of it and using up others' connection slots. As far as I know, SPV wallets are not relaying transactions or blocks, they are just like people on Torrent who download stuff but not share anything.

SPV wallets were Satoshi's idea. He knew they would be needed by people with low spec computers and metered internet connections. People have complained the Bitcoin core wallet can take a week to sync on a low power computer with a slow connection. They say if anything goes wrong whole it's syncing and the database gets corrupted you have to start the whole process again. My computer is too low power and has too little free memory to consider using the Bitcoin core wallet.

Not everyone has the choice to use the Bitcoin core wallet, some people have no option but to use SPV wallets.

"Here I have 100,000 USD and I'll put them in lowest-security bank because I have no money for better one". 

I use blockchain.info/mycelium as hot wallet and that's absolutely fine and needed in my opinion. however, I would never store a significant amount on them

[Amph]

there is also a warning on the forum(not for everyone) that is telling you to wait for 30 conf, before trusting a transaction, for those that are worried it is better to leave bitcoin alone for the moment, or upgrade to the last core version, if you're not using a light wallet