The "big block" movement is shifting to extended blocks. Will the dispute between BU and Core ultimately serve others?

Over the course of two years of the bitcoin scaling debate, few alternatives have advanced far enough to challenge the network’s most famous and longest-running software: Bitcoin Core.

The more prominent of these are Bitcoin XT and Bitcoin Classic, both alternatives that prioritize supporting larger block sizes as a way to expand Bitcoin’s transaction capacity.

However, a side effect of these ambitious proposals is that network users will need to switch Bitcoin implementations to make these changes, something not everyone wants or is willing to do.

All of this exposes an unspoken rule that has emerged in the scaling debate - alternative solutions not only need to propose a technical change, but also form their own developer team so that they can use it as a capital to put forward different opinions.

A recent well-known alternative solution is Bitcoin Unlimited, which allows miners and users to support the block size they want, but BU has suffered some criticism, one of which is that its code is poor - or at least immature. For example, in March this year, attackers exploited these bugs twice, causing most of the BU network nodes to shut down.

In this context, an implementation called Bcoin (created by bitcoin startup Purse) has entered the scaling debate with the potential to be a notable outcome in the scaling debate.

Purse’s proposal, which has received much fanfare since its announcement this week, introduces an old scaling idea called “e-blocks” as a way to get around today’s block size stagnation.

After complex technical discussions, the idea was deemed controversial, with some developers arguing that adding “extension blocks” would be unsafe.

Still, extension blocks have strong support, largely due to the technical capabilities of their development team. Notably, some BU supporters have expressed praise for the project.

For example, ViaBTC mining pool CEO Yang Haipo told CoinDesk that he supports Purse’s concept and the Bcoin team.

Yang said:

“I think extending the block is going to be the solution moving forward.”

The "promising" option

Overall, there is a growing consensus that Bcoin, an alternative Node.js implementation launched in September, has a stronger technical team than BU and other so-called “big block” teams.

Purse CTO and Bcoin developer Christopher Jeffrey, for example, was credited with building the software as well as an ongoing lightning network implementation, Plasma, which can be deployed on top of the software.

Meanwhile, Lightning Network co-author Joseph Poon also helped write the parameters for Bcoin’s implementation of the recently introduced flagship technology.

One of the reasons supporters believe the team’s technical prowess can be trusted is that in March, the BTC.com mining pool mined a block running the Bcoin software — the first block not based on the bitcoin source code.

Purse has released a technical draft and reference implementation code for implementing extension blocks on Bcoin.

That’s not to say Bcoin is trying to replace Bitcoin Core like other implementations. When Bcoin was first announced, Purse described it as a Bitcoin alternative with cleaner code that could coexist with other software versions.

Disagreements remain

Although Yang Haipo is confident about the extension block, not all BU supporters are confident.

For example, Olivier Janssens, a former Bitcoin Foundation board member, criticized the solution for being too complex, telling CoinDesk that the Bcoin idea is “too complicated.”

He said:

“People need to get over their fear of hard forks.”

However, many are talking about the positives of this approach, even if they may be more focused on other options for scaling.

Roger Ver, Bitcoin investor and operator of Bitcoin.com, who is one of the most outspoken advocates of Bitcoin Core alternatives, said:

“I like the idea of ​​extending blocks, but I think there is little risk in actually increasing the block size.”

BU developer David Jerry Chan compared this extended block technology to other available solutions.

“I think this proposal is more reasonable and better than Segwit.

Chan also said that BU developers are still discussing the proposal and that there is no “official opinion” from the team yet.

However, Bcoin has also been criticized for some things, including that no matter how good its technical team is, such a solution will take time to be reviewed. (For example, Segwit was reviewed and tested for nearly a year before its release.)

On the other hand, Purse CEO Andrew Lee believes that the Bcoin code is already available, so the review time may be shorter.

Indeed, according to the technical announcement, Bcoin will then be deployed to the Bitcoin test network for further review and parameter refinement.

Yang Haipo also thinks so:

“We have been waiting for more than a year. We can wait another three months.