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Bitcoin's ASICBOOST Problem Explained [pdf]

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Re: Bitcoin's ASICBOOST Problem Explained [pdf]

#11

Post by jcoffland »

mjevans wrote: post #2

Wasn't the entire point of picking SHA-256 to both check the integrity of the existing ledger (why it's a hash) AND as a proof of work lottery? The "problem" being that instead of being a proof of actual work, shortcuts in the work were found. It seems then that a good solution would be to force many different types of proof of work. Different basis of hashes are obvious, but maybe some type of actual work every so o…

> It seems then that a good solution would be to force many different types of proof of work.

This would create many more opportunities for finding shortcuts like ASCIBOOST. Some of them might be much worse.

Re: Bitcoin's ASICBOOST Problem Explained [pdf]

#13

Post by tromp »

jcoffland wrote: post #10

This is excellent. I've been trying to find a technical explanation of ASCIBOOST for some time. Most of the articles and discussions gloss over the details. It is possible that this is part of the reason some miners are blocking SegWit but there is more to it. Core (the main Bitcoin development team) promised to provide a block size scaling solution and then reneged. This pissed a lot of people off and led to the blo…

The AsicBoost inventors also wrote a good technical explanation at

https://arxiv.org/pdf/1604.00575v1

Re: Bitcoin's ASICBOOST Problem Explained [pdf]

#14

Post by Itsdijital »

petertodd wrote: post #6
wyager wrote: post #5

Earlier quoted context omitted.

> The "problem" being that instead of being a proof of actual work, shortcuts in the work were found. The same "problem" occurred when people invented GPU mining, then FPGA mining, then ASIC mining. As long as SHA256 isn't broken, it doesn't matter what kind of speedup miners manage to get; whenever someone finds a big advantage, everyone else uses it soon enough. > Different basis of hashes are obvious "Use more has…

> everyone else uses it soon enough. Unfortunately in this case, ASICBOOST is both patented, and adds a fair bit of complexity to mining hardware. Both these problems have the undesirable effect of increasing the barriers to entry for new asic manufacturers - an undesirable thing from the point of view of Bitcoin users. You're quite correct that shortcuts are irrelevant, but the reality of manufacturing makes the pla…

>ASICBOOST is both patented

China be like, lol "patented"

Re: Bitcoin's ASICBOOST Problem Explained [pdf]

#15

Post by tlrobinson »

jcoffland wrote: post #9
shea256 wrote: post #7

Earlier quoted context omitted.

Exactly, I'd go further and say that if a particular technique is patented and cannot be matched by a related technique, giving a permanent unfair advantage, it is up to the community to change the proof of work and work around the advantage imposed by a state monopoly.

Then Bitcoin has to hard fork every time someone comes up with a new patentable idea. I don't see why people think mining must be fair. It only has to not become completely centralized.

But if one miner has a significant advantage for a long enough time then mining will become unprofitable for everyone else, ultimately leading to nearly complete centralization.

Re: Bitcoin's ASICBOOST Problem Explained [pdf]

#16

Post by AgentME »

jcoffland wrote: post #10

This is excellent. I've been trying to find a technical explanation of ASCIBOOST for some time. Most of the articles and discussions gloss over the details. It is possible that this is part of the reason some miners are blocking SegWit but there is more to it. Core (the main Bitcoin development team) promised to provide a block size scaling solution and then reneged. This pissed a lot of people off and led to the blo…

>I don't see ASCIBOOST as a real problem for Bitcoin.

It often incentivizes miners to reorder or drop transactions until they hash to a specific value. (A certain mining pool is publishing a significant number of empty blocks.) Miners exist to verify transactions, and Bitcoin was designed with transaction fees in order to incentivize miners to include transactions. A competing force pushing miners away from including transactions that can be trivially fixed is just a bug.

Imagine a mining "optimization" which involved miners making only empty blocks. That goes against why Bitcoin has mining in the first place, and would delay transactions eventually to a halt as more took advantage of the optimization. A trick that only often encourages miners to make empty blocks isn't categorically different, and it's something suboptimal about Bitcoin that can be fixed.

Re: Bitcoin's ASICBOOST Problem Explained [pdf]

#17

Post by jlrubin »

tromp wrote: post #13
jcoffland wrote: post #10

This is excellent. I've been trying to find a technical explanation of ASCIBOOST for some time. Most of the articles and discussions gloss over the details. It is possible that this is part of the reason some miners are blocking SegWit but there is more to it. Core (the main Bitcoin development team) promised to provide a block size scaling solution and then reneged. This pissed a lot of people off and led to the blo…

The AsicBoost inventors also wrote a good technical explanation at https://arxiv.org/pdf/1604.00575v1

Notably, they don't include the optimal root generation algorithm, nor do they discuss segwit incompatibilities.

Also, their 20% figure is unclear. The more collisions you can find, the more hash per second you should be able to gain.

Re: Bitcoin's ASICBOOST Problem Explained [pdf]

#18

Post by jlrubin »

jcoffland wrote: post #10

This is excellent. I've been trying to find a technical explanation of ASCIBOOST for some time. Most of the articles and discussions gloss over the details. It is possible that this is part of the reason some miners are blocking SegWit but there is more to it. Core (the main Bitcoin development team) promised to provide a block size scaling solution and then reneged. This pissed a lot of people off and led to the blo…

Another problem with ASICBOOST is that it incentivizes a miner to try to partition the network such that the orphan rate increases, because mining on top of orphan blocks is more profitable.

If we have two competing successors (S_1 and S_2) to a Block B, an ASICBOOST miner can mine both simultaneously by creating Chunk 1's with different parent blocks.

I call it "The Oliver Twist Attack".

Increasing the Oprhan rate is incredibly costly to affected miners, this has the effect of making it also increase the hash rate of the attacker.

Re: Bitcoin's ASICBOOST Problem Explained [pdf]

#19

Post by [deleted] »

jcoffland wrote: post #10

This is excellent. I've been trying to find a technical explanation of ASCIBOOST for some time. Most of the articles and discussions gloss over the details. It is possible that this is part of the reason some miners are blocking SegWit but there is more to it. Core (the main Bitcoin development team) promised to provide a block size scaling solution and then reneged. This pissed a lot of people off and led to the blo…

[deleted]

Re: Bitcoin's ASICBOOST Problem Explained [pdf]

#20

Post by timq »

Just to point out that SegWit is everything but "already adopted in the industry". It turns out that SegWit is the solution promoted by the developers of bitcoin core to allow for bigger blocks, and solve some issues like transactions maleability. It's more than 10 000 lines of code highly controversial because they require... A soft fork, and will change bitcoin in a fundamental ways.

Not to add that a company called "Blockstream" have paid almost every developers of bitcoin core to push Segwit without a clear consensus from the community. Worse, this company actually support the huge censorship happening in bitcointalk and r/bitcoin. Blockstream received more than 75 millions from AXA, for obscure reasons.

The paper only focus on Segwit, without mentioning that Segwit has nothing to do with ASICBOOST. The community and a growing majority of miners is actually switching to bitcoin unlimited, a fork of bitcoin core.

Sorry for the little off topic comment but I love Bitcoin and I hate that a few dishonest people took control of it and try to destroy it.

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