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Mike Hearn calls Bitcoin’s block size debate a ‘civil war’

The Bitcoin block size debate, a technical dispute over an intrinsic aspect of the network, has been taken entirely too far for at least one core developer. Mike Hearn has lost faith in the system, and sold all of his coins.

The Bitcoin block size debate, a technical dispute over an intrinsic aspect of the network, has been taken entirely too far for at least one core developer. Mike Hearn has lost faith in the system, and sold all of his coins. Hearn is responsible for many important parts of bitcoin, such as the entire Java library, and now works on blockchain solutions with R3 CEV.

Mike Hearn“What was meant to be a new, decentralised form of money that lacked ‘systemically important institutions’ and ‘too big to fail’ has become something even worse: a system completely controlled by just a handful of people.”

  • Mike Hearn

Hearn posted an extensive blog clarifying his motives yesterday, “the fundamentals are broken and whatever happens to the price in the short term, the long term trend should probably be downwards. I will no longer be taking part in Bitcoin development and have sold all my coins.”

Even though Bitcoin Core is an open source project, not a company, there are only 5 developers with commit access to the code on GitHub. According to Hearn, these developers were chosen quickly, from “whoever was around and making themselves useful at the time.”

One of them, Gregory Maxwell, had an “unusual set of views,” states Hearn. “He once claimed he had mathematically proven Bitcoin to be impossible.”

Maxwell has contributed to many widely-used techniques in the Bitcoin space, such as the homomorphic key derivation used in BIP32 and trustless privacy-preserving techniques such as CoinJoin and blinded proof of solvency. He is also CTO of Blockstream.

Blockstream makes several scaling solutions that all work with a smaller block size, including The Lightning Network, Sidechain Elements, and Segregated witness. In Maxwell’s December developer list proposal to increase Bitcoin’s capacity, he made it abundantly clear that he views scaling bitcoin’s capacity at odds with keeping bitcoin decentralized.

Gregory Maxwell“With the available technology, there are fundamental trade-offs between scale and decentralization. If the system is too costly people will be forced to trust third parties rather than independently enforcing the system’s rules. If the Bitcoin blockchain’s resource usage, relative to the available technology, is too great, Bitcoin loses its competitive advantages compared to legacy systems because validation will be too costly (pricing out many users), forcing trust back into the system.”

  • Gregory Maxwell

Perhaps it is this difference in opinion on the blockchain function that has kept the debate going so long, with developers like Hearn, Gavin Andresen, and Jeff Garzik battling Maxwell and other developers like Adam Back and Peter Wuille, who are also employed by Blockstream. “Maxwell and the developers he had hired refused to contemplate any increase in the limit whatsoever. They were barely even willing to talk about the issue,” Hearn said.

Of course, the Blockstream employees are not alone, not by a longshot. The proposal Maxwell made in December, adding ‘Segregated Witness’ and keeping one Megabyte blocks, has the support of at least 31 developers, including the current head bitcoin developer, Wladimir J. van der Laan, a Dutchman who typically refuses to get involved in the politics of bitcoin.

In an attempt to provide a solution to the blocksize stalemate, Hearn and Andresen released an alternative version of the bitcoin core client in August, BitcoinXT. The software allows for block sizes that would scale up to eight megabytes, once 75% of bitcoin miners made the switch.

While the client gained a lot of support from miners and bitcoin companies early on, Hearn states that BitcoinXT was met with insurmountable opposition in the form of censorship within bitcoin community: “The release of Bitcoin XT somehow pushed powerful emotional buttons in a small number of people. One of them was a guy who is the admin of the website and top discussion forums.”

“XT could not be mentioned or linked to from anywhere on the official website and, of course, anyone attempting to point users to other uncensored forums was also banned. Massive numbers of users were expelled from the forums and prevented from expressing their views.”

  • Hearn

The administrator of various bitcoin communities, going by the name Theymos, responded by stating that “Bitcoin would need to be redefined to equal XT before XT would be allowed on /r/Bitcoin,, and […] XT needs to utterly defeat ‘old’ Bitcoin (including, etc.) on the market before I could recognize it as Bitcoin. This is messy, but it’s the only reasonable approach as far as I can tell.”

block size consensusUnfortunately, that wasn’t the only hurdle for BitcoinXT. Node owners running the client, including users, businesses and miners, reported massive and ongoing Distributed Denial of Services (DDoS) attacks. When Coinbase announced it’s support for BitcoinXT, their extremely robust website was taken offline for hours.

The censorship and DDoS combo has been so effective that it appears that even Gavin Andresen, BitcoinXT’s strongest supporter, has decided to back a new horse.

Bitcoin Classic appears to be the big-block camps new favorite client, toned down to a mere two-megabyte block size, which meets just about every pool and businesses wishes.

It’s not meant to be a final solution, just a fast one, and it has the added bonus of making future disagreements easier to solve. It doesn’t appear that the code is finished yet, but if it’s anything like BitcoinXT, there won’t be too many changes to make, so we should expect to see it completed soon.


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