Segwit2x initial code release, compatible with BIP148

The working group behind the Segwit2x bitcoin scaling proposal has announced that the initial version of its code has entered the review and testing phase.

The code release is the first time the technology has come to light as one of the most popular proposals to improve network performance. In May, it was brought together by miners and startups in the form of a "protocol" and Segwit2x is an alternative to the solution proposed by Core, the open source developer team of the Bitcoin network.

Since it was proposed, the plan has become a hotly debated topic, with both critics and supporters in the comments.

However, Segwit2x sends a positive signal that it may become a compromise option to avoid controversial network splits. In addition, Segwit2x seems to be compatible with another solution, BIP 148 User Activated Soft Fork (UASF). According to its code, UASF will be activated on August 1.

The news is notable because just earlier this week it seemed unlikely that there would be compatibility between the two proposals — a potential conflict that had the community worried about the bitcoin blockchain splitting into two competing assets.

That changed on Wednesday, when bitcoin developer James Hilliard submitted an improvement request that included a code change that could ultimately reduce the time that mining pools have to lock in updates.

Hilliard wrote on GitHub:

This will reduce conflicts with BIP 148.

By reducing the lock-up time, mining pools would have one (or two) to three days to lock in the controversial code improvement, Segregated Witness (SegWit), and use the SegWit2x software to show support for the proposal before the UASF activates on August 1. However, it is unclear whether mining pools will do so.

The application was well received and received several "ACKs" (acknowledgements), which is a developer's way of expressing "agreement".

Time is of the essence

The SegWit2x alpha release includes a running version of the software that includes two improvements: SegWit scalability optimizations and an increase in the 2MB block parameter.

According to an email from BitGo CEO Mike Belshe, the 2MB capacity increase is currently scheduled to take place three months after the activation of Segregated Witness. Prior to this, no one knew (even some SegWit2x participants did not know) when the 2MB hard fork would be executed.

Belshe said:

Segwit2x development is proceeding at a rapid pace as planned and the project is in good shape.

The 2MB expansion has always been a focus of controversy, partly because it could cause the blockchain to split if not everyone agrees to upgrade to the latest blockchain code. In addition, some people in the industry have stated that they will not support this approach.

However, Segwit2x has won the support of most major bitcoin companies and mining companies, representing more than 80% of bitcoin’s computing power. (Although it is unclear whether this support can be maintained given the community’s fatigue in dealing with the issue of scaling.)

With the release of this alpha version, the community now has a chance to audit and test the software. This release also includes a new Bitcoin testnet that developers may use to run Segwit2x software on to check for vulnerabilities.

Testing Phase

Over the next two weeks, developers can use this new test network, testnet5, to test the software.

Justin Langston, a senior developer at BitPay, said in an email:

We plan to run several rounds of testing on this new testnet5, and anyone in the working group can participate.

These rounds of testing will simulate the entire “lifecycle” of a code deployment, from supporting Segregated Witness to activating the 2MB block parameter.

The goal of these tests and audits is to avoid any potential network issues that could, in the worst case, cause users to lose their Bitcoins.

Langston said:

My thoughts are limited. We need your feedback on which tests are important to your company's application risk assessment and which tests will prepare you for deployment of this software in a live network.

Unknown safety?

Feedback on the SegWit2x initiative has already started to trickle in.

One working group participant said hard forks are likely to result in “replay attacks,” which would allow users to accidentally spend bitcoins on both networks at the same time when the blockchain splits and two bitcoin tokens emerge.

This also happened after Ethereum split into two tokens last year, resulting in financial losses for many companies.

This participant believes that avoiding replay attacks and other potential dangers is a must-have feature of the Segwit2x code.

Some Bitcoin Core developers have criticized the rushed development of Segwit2x, which was tested for more than a year before release, as it usually takes a long time to iron out all the bugs in a Bitcoin code improvement.

However, SegWit2x developers have not delayed development, saying the project can proceed as planned, with a beta version set to be released on June 30. By July 21, users will be able to run and fully audit the software.