Christian Decker, Core Tech Engineer at Blockstream, shares his views on soft-forks, layer-2, and discusses the development of Greenlight with Atlas21.
During the Tuscany Lightning Summit, discussions revolved around possible solutions for utilizing the Lightning Network in a non-custodial manner, especially those that do not involve managing an LN node.
Greenlight is certainly among the most innovative solutions in this regard. To delve into Greenlight and the future of the Lightning Network, Atlas21 interviewed Christian Decker, Core Tech Engineer at Blockstream.
Soft fork: proposals like APO, CTV, and others have been made to improve Bitcoin scalability. Upgrade or ossification: which side are you on?
There’s always a double-edged sword in these cases. Obviously, we would like more flexibility; we would like to build more advanced, smarter systems, and we would like more functionality. We all want that. The downside of activating soft forks is that we have very strict compatibility requirements, so anything we activate today, we should potentially maintain forever. We know there are a couple of discussions we’ll have to make a decision on eventually, but we have to be very cautious about what we activate because it’s a burden we’ll carry for a long time. So any issues we develop or any attack vectors we overlook will be in the system for a while. Therefore, as much as it pains me to see my proposal not being accepted right away, I think it’s sensible to weigh different proposals. And we shouldn’t get too attached to our proposals to be honest. We should really look at them neutrally and objectively evaluate them against each other. And if a different proposal offers us the same functionality as APO or CTV or TX hash, then that proposal should be fine too. So I can wait a long time before my proposal (APO) is accepted as long as it’s safe and provides us with the functionality we need. It’s not a sprint, but a marathon.
In the last few months, numerous layer-2 solutions have emerged. What do you think about the proliferation of these layer-2 solutions which, according to their narrative, aim to offer something that LN has not yet been able to provide?
LN isn’t the ultimate solution that will solve all problems at once. Like any system, LN has its limitations, just as Bitcoin on-chain and other layer-2 solutions do. However, I believe that Bitcoin on-chain and LN complement each other. If we can try out more layer-2 solutions, explore various tradeoffs and different requirements, these could become part of the complete solution that increases the protocol’s scalability, but none specifically will be the definitive one.
In this competition among layer-2 protocols, do you see a favored protocol over the others that will survive as Bitcoin has survived compared to all other cryptocurrencies? Do you see LN favored over other layer-2 protocols?
As in any industry, competition is a good thing. Competition drives progress and helps us improve. We should always welcome competition. I can’t say if a specific protocol will survive; there’s always a new one entering the market and one fading away and being replaced by another. LN is a stack of protocols that is evolving very rapidly; we might still call it LN in a decade, even though it could be very different from what it is today. It might be completely different; it might be composed of different components than the current ones. Will we still call it LN? I don’t know, but we will have something that has emerged from what LN is today and that will be better than what we have today because that’s how progress works for us.
Do you consider Liquid part of these layer-2 solutions?
It mainly depends on which aspects you look at. Personally, I would consider it a layer-2 simply because you have the possibility to move from the Bitcoin blockchain to the Liquid sidechain, by pegging in and pegging out. Alternatively, you can swap bitcoin to Liquid in a permissionless manner. The denominations are the same, and one of the key principles of Liquid is the fungibility of L-BTC and BTC. So, I believe that Liquid is a layer-2 with advanced functions, mainly because you can lock bitcoins on-chain and move to a separate chain and perform other operations faster and more privately, and then return to the mainnet.
Greenlight is a service that allows you to use the Lightning Network in a non-custodial manner. What do you think is the main feature of Greenlight?
Probably I would say the ease of use. We realized that managing an LN node might not be one of the easiest things in the world to do, and we were looking for a way to make it more accessible, basically to onboard the next generation of bitcoiners without exposing them to too many technical details. Also, because if you need to learn a 1,000-page tome before you can use Bitcoin, people get demoralized and give up. Our goal is essentially to provide a secure system, one that agrees with the principle ‘not your keys, not your coins,’ but at the same time take responsibility for the complex part, allowing a user who is having their first experience with Bitcoin to have a good first experience and only then explain to them how it works under the hood. So for us, Greenlight is essentially a system that we would like to use to onboard the next million Bitcoin users, in such a way that they can start their journey easily, and only when they have all the necessary tools and skills can they take responsibility for managing an LN node and become independent and sovereign bitcoiners.
You’ve stated that with Greenlight, you want to onboard the next million Bitcoin users: I imagine you aim to attract not only Bitcoin users who want to use Bitcoin in a non-custodial manner, but also people who want to use payment applications that are not strictly involved in the Bitcoin ecosystem, correct?
Yes, absolutely. We have different target audiences for Greenlight: one target is definitely end users whom we want to learn how to manage an LN node and have a good experience; another target is definitely developers and the applications themselves that may be external to the Bitcoin world. Food delivery apps, railway ticket apps, or any application involving payment. We want to offer them the opportunity to integrate Bitcoin and therefore have their users exposed to Bitcoin. We want them to learn what Bitcoin is and perhaps choose Bitcoin as a tool for their finances. This is a way to introduce Bitcoin to non-bitcoiners, and to do this, we need to simplify some things. We need to take responsibility for managing LN nodes to make it easier for them to use for the time it takes them to learn and to upgrade their experience to what we consider to be the right experience for bitcoiners. Essentially, having the knowledge and experience to be completely self-sovereign.
I imagine that onboarding a large number of new users through a technology like Greenlight also allows for better functioning of the LN. The more people join the network, the more efficient the LN becomes, right?
Absolutely. Essentially, by adding more utility to the network, making it more useful for users, we are not only providing a service to users, but at the same time, we are incentivizing users themselves to be part of this network and to contribute to being part of the LN routing infrastructure, for example. Certainly, our hope is to increase utility for everyone. Ultimately, it’s a network, so it’s logical that there would be some sort of network effect.
Could this also be a way to silence the criticisms that have been made against the LN in recent months? Do you believe that these improvements, namely building technologies that allow millions of people to enter the LN, could be a way to make the LN more scalable?
Certainly, because we are adding value to being part of the network. Suddenly, it is very valuable to have professionals who know how to manage an LN node learning, sharing experiences, and experimenting with different trade-offs. They see what works and what doesn’t, as suddenly there is a possibility of earning due to increased traffic and network usage, and this can help us strengthen the network, learn how the network works inherently, and essentially improve overall performance over time. Currently, there is a lot of experimentation, many myths or ideas about what may or may not work. But time will tell us what works and what doesn’t. And we as node operators will learn how to make better use of the resources we have available. I think it’s a great collective learning experience.
