If Sidechains Existed, The Block Size Debate Would Be Irrelevant

During a recent interview with Epicenter Bitcoin, Blockstream Co-Founder and President Adam Back was pushed for clear answers on the topic of Bitcoin governance by Brian Fabian Crain. Although Back explained that the BIP process had worked well for coming to consensus in the past, Crain was interested in what would happen in a scenario where a compromise could not be found and the Bitcoin development process hits a dead end. Eventually, Back contended that sidechains are needed to make many of the more controversial changes to the protocol possible.

Adam Back Tries to Improve Bitcoin Privacy

When asked specifically about how the Bitcoin development community will be able to come to consensus on controversial issues in the future, Back responded by first telling the story of what happened when he originally tried to bring some privacy-enhancing features to the network.

“The reason I became interested in sidechains is because when I got interested in Bitcoin and caught up with all the protocol details, then I tried to find ways to improve Bitcoin. I’m from an electronic cash [and] cryptography background, so I found a couple of ways to improve Bitcoin’s fungibility, privacy, and things like this. Then, I went to talk to the [Bitcoin] Core developers and said, ‘How about implementing this?’, and it became apparent that because what I was asking for was relatively complicated [and] somewhat high-risk because of the amount of code involved they were quite interested in the features but it was very difficult to implement them in a really short period of time. And that’s basically a symptom that the core protocol is about providing a secure and useable base that people can build things on top of. You could think of it, maybe, a bit like TCP/IP or something.”

In Search of a Solution for Faster Development

Bitcoin Core developers and contributors are notoriously conservative when it comes to changes to the base protocol, and there’s an excellent reason for that — nobody wants to be the one who breaks Bitcoin and destroys billions of dollars of investment overnight. Back’s inability to bring his privacy enhancements into Bitcoin Core is eventually what led him to sidechains. He explained this point during his Epicenter Bitcoin interview:

“How could we add a layer or a way to do this faster? And that’s what sidechains are. It’s a way for different people to work on different features independently and without them having to be in Bitcoin Core, sort of layering so you do things on layer 1 instead of layer 0.”

Although Bitcoin is a platform for permissionless innovation, developers still need the permission of their peers to make changes to Bitcoin Core. With sidechains, developers are allowed to experiment freely on alternative blockchains that do not require the creation of a new altcoin.

Making Developer Debates Irrelevant

In short, sidechains (and other, similar proposals) are what Adam Back sees as the solution to the consensus issues facing the Bitcoin development process right now. In terms of the block size limit debate, Back noted that someone could have simply implemented a higher-scale sidechain in a scenario where the technology was already available to developers:

“If some of these generalized extension mechanisms that allow people to implement novel features or features that may not even be mutually compatible in parallel — if that kind of extension framework, which might be sidechains or extension blocks or something proposed by other people — if that were implemented before the block size, you know, before we got close to some kind of scaling issue, the answer would have been quite different, which is somebody would have used the extension to make a higher-scale, opt-in extension.”

Perhaps we would be talking about Gavin Andresen and Mike Hearn’s BIP 101 sidechain rather than Bitcoin XT if sidechains had been implemented earlier this year. Although the timeline for the deployment of sidechains is still unclear at this point, it’s possible that they could be a powerful tool in eventually leaving all of this development drama in the past.