A few weeks ago, the relatively new India-based bitcoin mining pool GBMiners decided to switch their software from Bitcoin Core to Bitcoin Unlimited. Bitcoin Unlimited is software that creates an alternative protocol and network based on Bitcoin, if a majority of miners decide to implement a new method for increasing Bitcoin’s current block size limit.
Whether Bitcoin Unlimited would initiate a Bitcoin hard fork or effectively constitute the creation of an altcoin depends on what people decide to refer to as Bitcoin after the new chain is activated.
Bitcoin Magazine reached out to GBMiners to learn more about why they decided to make the switch to Bitcoin Unlimited. GBMiners Founder Amit Bhardwaj responded on behalf of the mining pool.
Segregated Witness Is Not the Right Solution
Like many others who would like to see transaction capacity increased on the Bitcoin network via a hard fork, Bhardwaj displayed urgency in his reasoning for switching to Bitcoin Unlimited. “It is high time when bitcoin needs to scale,” he said. “The transaction fees are going higher and higher, and [the] real essence of bitcoin lies in its use [as an] affordable currency.”
Bhardwaj referred to Segregated Witness (SegWit), a proposed soft-forking (backward compatible) change to Bitcoin that includes an increase in the effective block size limit to more than 2 MB (after users upgrade to SegWit-enabled wallets), as a “small to medium level increase in the network capacity.” In his view, Bitcoin Unlimited offers the best long-term scaling solution without altering how Bitcoin has worked in the past.
Although some would consider the increase to the block size limit enabled by Segregated Witness as modest, one of the main points of this protocol change is to enable a more efficient version of lightning networks. To this point, Bhardwaj argued, “It might work for things like micropayments, but if we consider bitcoin becoming a mainstream currency and people getting their salaries in bitcoin, then even post-SegWit we would need a block size increase.”
When asked for further details on why Segregated Witness is not an acceptable improvement for Bitcoin, Bhardwaj pointed to a Medium post from a pseudonymous author that talks about the change as an ineffective and irresponsible protocol upgrade.
“The technical debt that the update adds to the network is the biggest concern,” said Bhardwaj. “We are not able to predict the impact of such a big change to the underlying operation of the bitcoin transactions. SegWit comes with its own complexities — the downsides of which are completely unknown to us.”
In Bhardwaj’s view, a block size increase is needed as soon as possible via a hard fork, which he believes would come with less code complexity and no unforeseen bugs. “It is a simple change where the active community of miners, wallets and exchanges just have to coordinate and upgrade,” said Bhardwaj. “It makes all the sense in the world to first do the thing with less uncertainty and low probability of failure. Also, we are not fundamentally against SegWit. It just is not the best solution for the biggest and the most important problem at hand, which is scaling.”
Although Bhardwaj is against Segregated Witness as a solution to Bitcoin’s scaling concerns, he does see value in other features enabled by the improvement proposal.
How to Hard Fork Safely With Bitcoin Unlimited
While Bhardwaj claims increasing the block size limit via a hard fork is not a complex alteration in terms of code changes, the controversial aspect of such a change is that it requires a hard fork (and thus all users moving over to a new network), which can be difficult to coordinate—unless the proposed change is itself uncontroversial.
When asked how a hard fork could be pulled off in a safe manner, Bhardwaj pointed to another Medium post, which was published by the ViaBTC bitcoin mining pool. The post is essentially a safety guide for miners who wish to run Bitcoin Unlimited instead of Bitcoin Core.
In the post from ViaBTC, it is recommended that miners wait for at least 75 percent of blocks to be mined by mining pools that are signaling for Bitcoin Unlimited for three straight difficulty periods (roughly six weeks). Having said that, Bhardwaj believes a hard fork initiated by miners running Bitcoin Unlimited only needs more than 60 percent support from the network hashrate to be considered safe.
One of the main concerns with any hard fork is the potential for the fork to result in two competing blockchains, essentially splitting the Bitcoin network in half. This is what happened on the Ethereum network when the hard-forking bailout of DAO token holders led to two competing chains: Ethereum and Ethereum Classic.
“We believe if the hard fork is executed as per the Bitcoin Unlimited plan, we would be able to prevent splitting or at least make the new Bitcoin [the] primary one,” said Bhardwaj when asked about the potential for a network split.
In a scenario where there is indeed a split of Bitcoin into two separate networks, Bhardwaj claimed such a scenario would be a “minor set back in the large vision of Bitcoin.”
Thoughts on Bitcoin Core Developers
In addition to his support for Bitcoin Unlimited, Bhardwaj also feels that the various contributors who work on Bitcoin Core are incapable of handling further development of the Bitcoin protocol on behalf of its users.
“The scaling problem [has been] actively discussed for the past three years now, and yet, the community has not been able to come to a consensus,” said Bhardwaj. “It is extremely clear that the people we are banking on to take care of the development of the protocol are probably not able to do justice to the expectations of its users despite their best intentions. The present stalemate is a clear example; the transaction fees on the system [are at an] all-time high, and SegWit adoption has stagnated.”
When asked if he has ever communicated with any of the Bitcoin Core contributors, Bhardwaj first responded that the ideas of Bitcoin Unlimited and Bitcoin Core need to be merged to produce the best possible version of Bitcoin. When pushed further, Bhardwaj responded, “No, we [have] not connected to any Bitcoin Core Developer yet.”
According to one Bitcoin Core contributor, multiple attempts have been made at opening a dialogue with GBMiners.
In his final comments, Bhardwaj clarified that GBMiners has nothing against the group of Bitcoin Core contributors currently working on the project. “We have immense love and respect for their efforts so far, but our love for making bitcoin a currency for the masses is fundamentally greater,” he said.