专访Zulu Network CTO：成为比特币网络中真正的L2扩展层

原文来自：星球日报

作者：Wenser

As the competition in the Ethereum L2 network enters a white-hot stage and the Bitcoin network ecosystem becomes increasingly rich, the Bitcoin L2 network has become the next crypto highland. As a Bitcoin L2 network rookie that adopts a two-layer architecture and has recently successfully developed and implemented ZKP verification, Zulu Network is expected to be the first to connect the Bitcoin L1 network, Bitcoin L2 network and L3 network.

Odaily Planet Daily recently conducted an in-depth interview with Zulu Network CTO Cyimon to share the behind-the-scenes story of the Bitcoin L2 network.

Q: Could you please give us a brief self-introduction, such as your past work experience, and what your responsibilities are after joining the Zulu Network (hereinafter referred to as Zulu) team?

Cyimon: I entered the blockchain industry in 2018, mainly focusing on the ZK field. I have about six years of technical experience. I joined the Zulu team in October last year. The reason why I chose the track of Bitcoin Layer 2 is mainly because I saw the release of the BitVM white paper. Based on these theories, we can truly implement the vision of Bitcoin Layer 2. After joining the Zulu team, I am responsible for the coordination of technical directions and development-related work. We will also introduce this in detail later, including Zulus unique design and current technical progress. Overall, our Zulu is an ecological network that wants to bring more extended functions to Bitcoin.

It is worth mentioning that as the industrys first Bitcoin L2 project to complete the simulation implementation of ZKP on Bitcoin through the Bitcoin Script language, Zulu has also made a lot of contributions to the BitVM 2 official GitHub code repository, and has therefore been highly recognized by BitVM inventor Robin Louis.

Tweets by Robin

Q: What challenges are there in building L2 based on the Bitcoin network? What technical implementation solutions do other Bitcoin L2 networks on the market use?

Cyimon: I think this question is very critical and directly reflects the core vision of Zulu. As a Bitcoin L2 network, or before the popularity of the Bitcoin L2 network, most people have heard of the Ethereum L2 network. Whether it is Bitcoin L2 or Ethereum L2, the main problem is: as an off-chain network of a public chain, how can the L2 network inherit the security of the L1 network?

For Ethereum, this is a relatively simple task, because it is already very mature, such as being able to verify ZKP and having certain programmability. However, on the Bitcoin network, this is a rather embarrassing thing, because the limitation of ZKPs own programmability directly leads to the inability of the on-chain state of the L2 network to be directly verified on the Bitcoin network. Because of this limitation, many Bitcoin L2 networks on the market now actually have no direct relationship between their on-chain state and the Bitcoin network itself. In other words, their on-chain state may claim that they can generate a ZK proof, but this proof has never been verified on the Bitcoin network. So from a certain perspective, these Bitcoin L2 networks are more like a side chain, so I think a key challenge facing the construction of L2 networks based on the Bitcoin network is how to make the L2 network enjoy the security of the Bitcoin network without forking the Bitcoin network itself.

The security here mainly involves two aspects: the first aspect is the economic security of the Bitcoin network, that is, a POS network can be formed by staking to maintain the verification of the off-chain status. If there is a problem, the corresponding assets will be confiscated; the second aspect is the network security of the Bitcoin network itself, that is, the POW network security. In this state, ZKP verification is not performed through the staking node network, but by placing it on the Bitcoin network. This is what we really want to do, and it is also a key problem that a Bitcoin L2 network must solve, that is, how to inherit the security performance of the Bitcoin network? Therefore, in fact, the on-chain security of other Bitcoin L2 networks is not very related to the Bitcoin network. A difficult problem involved here is how to complete ZKP verification on Bitcoin?

Zulu has actually been focusing on how to achieve programmability and ZKP on the Bitcoin network since the release of the BitVM white paper. After several months of hard work, we finally announced a phased result last week, which is that ZKP verification can now be achieved using Bitcoin scripts (Note: For details, see Zulus open source code for implementing ZKP verification using Bitcoin Script, involving the Groth 16/FFlonk mainstream algorithm ) . This is a very significant technological breakthrough in the industry. It means that once zk verify can be implemented through Bitcoin scripts, then the punishment of the malicious party can be achieved through a challenge mechanism similar to Arbitrum. Therefore, this is equivalent to enjoying the security of the Bitcoin network in an indirect way. Compared with other Bitcoin L2 networks, this is Zulus original technical implementation method and a leading solution.

Q: In terms of design ideas and concepts, how do you understand the two-tier architecture mentioned many times in official documents? For example, features, functions, competitive advantages, etc.

Cyimon: We need to talk about the design concept behind Zulu, so that friends who don鈥檛 know much about technology can understand the two-tier architecture intuitively and clearly.

To talk about this, we must first clarify: Why does the encryption industry need L2 network or why does Bitcoin need L2 network more?

As mentioned in the first question, where does the security guarantee of Bitcoin L2 network come from? The reason why Zulu adopts a two-layer architecture is more for functional considerations. Taking Ethereum as an example, because it has programmability, the Ethereum L2 network mainly helps the L1 network solve two problems: one is TPS, and the other is operating cost. But for the Bitcoin network, in addition to the cost and TPS issues, our same L2 network can provide expansion support and realize functions that the existing Bitcoin network has not yet realized. This is the reason for the design of the two-layer architecture. Back to Ethereum, in the early design period, the Ethereum network was not a native environment friendly to ZK, and the emergence of the L2 network or the development route centered on Rollup provided a test field for more innovative designs. In other words, some innovative functions or technologies can be tried on a small scale in the L2 network. If the technical superiority is verified and recognized on a larger scale, it can be fed back to the L1 network. This is also the reason why Ethereum gradually integrates Rollup and ZKEVM in the L1 network.

So returning to the Bitcoin network, while helping the Bitcoin network expand TPS and reduce operating costs, functional expansion is also an important part.

This involves another layer in our two-layer architecture – the L3 network, which can be simply understood as a functional expansion layer, that is, while maintaining the original UTXO asset type of the Bitcoin network, it increases its programmability. This also lays a certain foundation for more entrepreneurs to engage in research and development work on this basis in the future.

The main goal of the L2 network that has been launched is DeFi, which is exclusive to the Bitcoin network, or what we generally call BitcoinFi in the industry. Because the Bitcoin network and Bitcoin itself are high-value assets, if we want to revitalize these assets, we generally prefer to adopt a more mature DeFi framework. Zulus L3 is an expansion platform based on UTXO programmability, which often uses a newer programming language and a new virtual machine. If you want to build DeFi applications right away, there may be so-called security risks. Therefore, before this, in order to facilitate the existing Bitcoin assets to quickly enjoy the relatively mature DeFi applications in the industry, Bitcoin L2 compatible with the EVM network has become the best solution, that is, to release existing liquidity through applications with relatively high security. The L3 network is to pave the way and lay the foundation for more development and innovation in the future. This is Zulus current major competitive advantage.

Because most Bitcoin L2 networks are currently EVM-compatible or only EVM-compatible, which means that users Bitcoin assets can flow to DeFi applications, but for industry users and the Bitcoin network, there is relatively little innovation or increment, because the gameplay is not much different from Ethereum. Therefore, Zulus two-layer architecture has more room for development compared to other Bitcoin L2 networks.

Finally, let me emphasize our security. As mentioned earlier, our security implementation is mainly reflected in the fact that the L3 network will be terminated on the L2 network, and then the status of the L2 network will enjoy the network security of the Bitcoin network itself through ZKP verification, which is also our latest development. In this respect, Zulu is the only Bitcoin L2 network that can enjoy the security of the Bitcoin network.

Q: I have learned about the development progress of technologies such as Zulu bridge and Lwaiz V4 before. Can you elaborate on it?

Cyimon: Lwazi V4 is the code name of the testnet version. Zulu bridge is currently developing a unique bridging tool that can be used to verify the off-chain status through ZKP at the Bitcoin network level, which is the core value of Zulu. If we talk about user participation, we will release a trust-minimized Bitcoin bridge later, and users can participate in the cross-chain and bridging of assets on the Bitcoin network. At the same time, user participation can also help us test the security and convenience of Zulu bridge. For details, please pay attention to the release of subsequent official documents.

Zulu network three-layer design architecture

Q: From the perspective of the end game, what application scenarios does the Bitcoin network need to support, and what are the necessary components of the ecological architecture? And will the Bitcoin network generate N L2 networks like the Ethereum network?

Cyimon: The question of Bitcoin network application scenarios deserves to be answered first.

At present, we can find that in addition to Bitcoin, there is actually no second asset in the Bitcoin network. This is actually a very exaggerated thing. Including the previous inscriptions and the rune project that was popular some time ago, none of them broke through the asset framework of Bitcoin. So, I think the Bitcoin network and Bitcoin itself contain huge energy. Specifically for application scenarios, the first thing is to activate existing assets like Babylon, and truly release the liquidity energy of these assets through pledge or other behaviors. This is one. Whether it is possible to do something to enhance network security on the basis of activating existing assets is also a very worthwhile application scenario. This is also the reason why some projects choose the asset pledge or re-pledge track of the Bitcoin network. Of course, these popular projects are based on the background of huge funds in the Bitcoin network, that is, to realize the appreciation of Bitcoin network assets.

Given that the Bitcoin network currently has no other high-market-value projects, another important scenario is to support programmability based on the Bitcoin asset type, thereby providing developers with the possibility to develop diversified applications based on the UTXO asset type. Taking the previous Ordinals protocol as an example, many index indexes are centrally operated, and different platforms have different operating standards, which leads to differences in the mutual recognition of assets. If development is based on expanding UTXO programmability, then the index can be written into a unified standard recognized by the industry, such as the so-called smart contract form.

The concurrency capability based on the extended UTXO (because the spending of each UTXO can be independent, unlike the account model, which can only send transactions one by one) can provide support for many scenarios that require concurrent processing capabilities, thereby providing support for the industrys mass adoption.

As for the necessary components of the ecological architecture, I think the core part is the bridge, that is, how to achieve the secure transfer of assets between the Bitcoin network and the L2 network. At the same time, it is also necessary to ensure that the L2 network enjoys the security protection of the Bitcoin network. This is a very important module.

Finally, regarding the number and development pattern of Bitcoin L2 networks, my current feeling is that the development of Bitcoin L2 network has borrowed a lot from Ethereum, so there may not be as many L2 as Ethereum, which is not the style of Bitcoin network. Bitcoin L2 may release chains of different virtual machines in the future. For example, some projects build EVM compatible networks on Bitcoin network, some projects build Solana virtual machine compatible networks, and some build Move language virtual machine compatible networks. As far as I know, some people are trying to build SVM and move it to Bitcoin, because one of the more important reasons here is that Bitcoin L1 network does not have a virtual machine, so L2 network can move different types of virtual machines, so Bitcoin L2 network will have greater differences than Ethereum L2 network. For example, Zulus L3 network runs a virtual machine that expands UTXO, unlike Ethereums L2 network, many of which are reinventing the wheel, so the Bitcoin L2 pattern is definitely different. Because if a project wants to achieve more benefits, it needs to make more combined innovations on Bitcoin L2 network, rather than directly copying it.

Q: Can you briefly share with us the development stages of Zulu and the key milestones in the next three to six months?

Cyimon: Overall, it mainly includes 3 parts.

First, the most important part of L2 network is Zulu bridge, which is the bridge.

Second, regarding the release of L3, all of this is inseparable from our community members and our technical development team, who will work together to experience the test network and complete the test as soon as possible. We will also make timely official announcements on important activities and technical iterations.

Third, our Zulu team will uphold the entrepreneurial spirit of the Bitcoin community and gradually open source various mature technologies and functions to facilitate more projects to adopt our secure solutions, benefit more projects in the market, and further enrich the development of the Bitcoin ecosystem.

In terms of time nodes, these three parts will be carried out in sequence. Our current goal is to bring Zulu bridge and testnet to the market before the end of the third quarter of 2024 to encourage more users to participate. As for the specific time, the development of the bridge is a difficult technical task, and there are no mature solutions or products to learn from, so we are gradually overcoming difficulties. It can only be said that we have already implemented the most critical and difficult part, and we need to iterate the challenge protocol and confiscation protocol based on the existing modules in the future. After all these are completed, the minimum trusted bridge can be pushed to the testnet.

Q: In terms of ecosystem construction, from the perspective of technology developers, what plans or standards will be considered for selecting developers, applications, and partners?

Cyimon: From a technical perspective, in terms of partner selection, for the sake of developing the Bitcoin ecosystem, Zulu is also looking forward to the emergence of more excellent projects and teams, such as Babylon and Nubit, to solve DA problems, solve the economic security problems of asset pledge, etc.

Because what Zulu wants to create is a real Bitcoin L2 network, which means that it can not only help the Bitcoin network to expand its functions, but also enjoy the security guarantees of the Bitcoin network. The security guarantees include both the economic security of the Bitcoin network and the network security of the Bitcoin network.

Specifically, economic security is to form a POS network by staking Bitcoin to protect the correctness of the off-chain state of the Zulu network. Once someone suspects that there is a problem with the Zulu network, they can initiate a challenge on the Bitcoin network and execute the challenge on the Bitcoin network. At present, this is a function that only Zulu can achieve, and this is also the focus of our subsequent cooperation with Babylon: they provide a relatively complete asset confiscation mechanism; we serve as an off-chain execution operation network. At the same time, considering the data load problem of the Bitcoin network, we also tend to store data in the partner network that focuses on the Bitcoin ecosystem DA application. Therefore, when choosing partners, we pay more attention to mutually beneficial cooperation.

As for the developer ecosystem construction, I think it is the same as the traditional model. First of all, Zulu is providing a stage for developers, which is a very meaningful thing. After the L3 network is launched, Bitcoin ecosystem developers will be able to conduct diversified development attempts and application explorations on it. We will also invest a lot of energy and funds to help the Bitcoin ecosystem expand more application scenarios, especially based on the expanded UTXO type, to try to issue more types of assets fairly.

Moreover, based on the parallel mechanism, Zulus L3 network also supports the implementation of more innovative gameplay, and the so-called Mass Adoption is no longer a castle in the air.

Zulu official website interface

Q: Will Bitcoin lightning payment and lightning network develop rapidly in the future? As mentioned in the Bitcoin white paper, its original design was a peer-to-peer payment system, but now people pay more attention to its asset value and regard it as digital gold. What do you think about this?

Cyimon: I personally think that Bitcoin is now equivalent to precious metal assets such as gold. Therefore, few people are willing to trade it. Most people want to hold Bitcoin and try to get more Bitcoin. So regarding the issue of Lightning Network, there are developers around me who are working on related things. I hope they can promote Lightning Network to a wider range of applications.

Q: Finally, what is Zulus ultimate vision and what are the milestones for different stages? Is it more data-oriented or something else?

Cyimon: Regarding Zulus ultimate vision, I think it can be summarized in one sentence: it is committed to helping the Bitcoin network achieve functional expansion, or in other words, Zulu is the real Bitcoin network expansion layer, and the expansion here includes a lot of content: including performance expansion, cost reduction and ecological expansion. In addition, I also like Babylons market positioning, which is to play the economic value of 21 million bitcoins. In contrast, we prefer to achieve an all-round expansion of the Bitcoin network. (Reporter asked: Does it mean a bit of ecological combination?)

Cyimon: Yes, as for different milestones, we pay more attention to the iteration and update of technology, because we think Bitcoin has lagged behind other public chains in terms of infrastructure, but it is the ecological network with the largest economic value. Therefore, we will continue to focus on the three major areas of Zulu bridge, L3 network and Bitcoin ecological expansion as our goals that we need to continuously break through. (Reporter added: It is indeed the perspective of a technician, which is very similar to the V1, V2, and V3 versions of product updates and iterations.)

Q: Finally, are there any stories you can share about the flashes of inspiration that occurred during the Bitcoin ecosystem or technology development process?

Cyimon: Sure. There happens to be an interesting industry misunderstanding that I would like to take this opportunity to clarify and express my personal opinion. I hope that more people will understand the design of Zulu bridge, especially the part related to BitVM. Because many projects in the market claim that they are built based on BitVM and are building their own bridges, but there is a big misunderstanding involving the BitVM bridge.

Robin, the inventor of BitVM, did write a bridge design in BitVM. However, this bridge is different from the Ethereum bridge. Strictly speaking, it is not open to ordinary users for asset transfers. Instead, it is a bridge focused on asset issuance, so it is more designed for fixed-amount inflows and outflows.

For example, it can be understood as a centralized entity that issues an asset on Ethereum, such as WBTC. Users use the bridge based on their trust in this centralized entity, allowing the centralized entity to control this centralized asset. However, the BitVM bridge is actually designed to facilitate the project party to issue bitcoins on its own L2 network or other chains with corresponding value binding on the Bitcoin network itself. Therefore, the BitVM bridge is designed to issue assets, not to serve ordinary users cross-chain assets. Of course, Zulu will also publish relevant articles to explain the specific details and precautions in the future. We will give a detailed explanation of which cross swap based on BitVM is used for asset issuance and which is used for ordinary users asset transfer, but here we only mention the most intuitive limitation, that is, once a user crosses 1 bitcoin, and then makes money through operations, this 1 bitcoin becomes 1.5 bitcoins, but it cannot be crossed back, because now the bridge limits users to only cross 1 bitcoin back, so once the users assets change, the bridge may not be able to be used normally, and this mechanism is also in an invalid state. Therefore, this bridge is not for ordinary users.

This article is sourced from the internet: Exclusive interview with Zulu Network CTO: Becoming the real L2 expansion layer in the Bitcoin network

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