Dialogue with Linea Product Leader: How does Linea, backed by ConsenSys, achieve "progressive" decentralization?

Interview: bayemon.eth, ChainCatcher

Guest: Declan Fox, Head of Product at ConsenSys Linea

On July 18, the Layer2 network Linea developed by the ConsenSys team announced the opening of Linea Mainnet Alpha access to the entire community at the EthCC conference. Since its launch, the total locked value (TVL) of Linea Mainnet Alpha has skyrocketed, surpassing $30 million at its peak, and currently stabilizing around $28 million.

Source: L2BEAT

According to RootData, projects such as AltLayer, OKX, LayerZero, Orbiter Finance, Polyhedra Network, Galxe, and Omnisea have already integrated into the Linea ecosystem.

Additionally, thanks to the backing of the ConsenSys team, Linea's mainnet is natively built into MetaMask, allowing users to skip the complex process of manually adding networks and switch directly to the Linea network in their MetaMask. In the future, Linea and MetaMask will also be deeply integrated. Coupled with the ConsenSys team's strength in U.S. regulation and crypto compliance, Linea undoubtedly possesses unique advantages that other L2s lack.

Why did ConsenSys, which has created well-known applications like MetaMask and built infrastructure platforms like Infura, choose to launch a Layer2 zk Rollup in a seemingly saturated Rollup solution market and join this fierce competition?

As Ethereum continues its transition to 2.0, scalability is certainly an important issue. However, there are currently voices criticizing existing Layer2 Rollup solutions for violating the principle of "decentralization" by using centralized sequencers and validation mechanisms. How will ConsenSys, which has always emphasized decentralization, break the deadlock between "user experience" and "decentralization"? Meanwhile, how will the Linea team, which has announced that there are currently no plans to issue tokens, attract more developers and users to participate in the construction of the Linea ecosystem and community?

To discuss these questions, ChainCatcher invited Declan Fox, the head of product at Linea, to talk about how the Linea team, backed by ConsenSys, will handle the seemingly "irreconcilable" contradictions between user experience and decentralization in the current technological environment, and ultimately achieve the team's vision of progressive decentralization.

Declan Fox, Head of Product at Linea

What makes Linea unique?

1. ChainCatcher: Please briefly introduce Linea.

Declan: Thank you for the invitation from ChainCatcher. I am Declan, currently the head of product at Linea. Linea completed its mainnet launch in mid-July and opened to the public on July 18. We have been busy preparing for the mainnet launch for the past year. In fact, we launched a developer-focused testnet on January 9 this year, which achieved remarkable success in the following 6 to 7 months.

Our team is excited and proud of the official launch of the mainnet. In the past few weeks, about 150 projects have integrated Linea and become our partners. Linea has also achieved an astonishing volume of transactions and bridging value with Ethereum.

2. ChainCatcher: Please briefly introduce the current size and division of labor within the Linea team.

Declan: First of all, as a zk Rollup scaling solution, we use zero-knowledge proofs as the underlying technology for transaction validation. This innovative technology relies on extensive research work, so Linea has a dedicated team of researchers focused on zk technology development. Before the Linea team was formally established, this work was carried out by the R&D team at ConsenSys, and some members of the Linea team come from the previous ZK research team at ConsenSys.

In addition to researchers, another important component of Linea is software engineers, who are responsible for building Linea's distributed solutions. I personally oversee the product aspect, and Linea also has members responsible for marketing and other support. Currently, the Linea team is small but experienced. If the scale of the Linea network continues to grow rapidly in the future, our team will expand to meet the market and technological demands of the next phase.

3. ChainCatcher: ConsenSys has created very successful applications and infrastructure like MetaMask and Infura. What goals does Linea aim to achieve?

Declan: The goal of Linea is actually to achieve scalability for Ethereum. A few years ago, we believed that Ethereum itself was not scalable, which was the original intention of our community to explore scaling solutions. Now, we can confirm that among various types of Ethereum scaling solutions, Rollups are the best solution. At the same time, zk technology, which can provide users with lower gas fees and higher throughput while ensuring security through cryptographic means, is a valuable technology that helps enhance the performance of Rollups.

Currently, Linea is already a relatively complete Layer2 zk Rollup network, but there is still much room for further exploration in this field to enhance Ethereum's scalability. We believe that as scaling theories and public chains continue to develop, more Ethereum scaling solutions will be built, and more users will participate in Web3 activities, unlocking the community's infinite potential and bringing broader prospects for Web3.

4. ChainCatcher: In the entire zk Rollup track, StackWare and Matter Labs have already launched zk Rollup scaling solutions since 2018 and 2019. Why did ConsenSys choose to launch Linea at this time and join this seemingly heated competition?

Declan: Interestingly, we actually started this project about five years ago, but at that time, our research focus was on zero-knowledge proof systems. Around January 2019, we began to delve into zkEVM, although the concept of zkEVM did not exist at that time.

At that time, many people were focused on Optimistic Rollup, and those who wanted to enter the field of zero-knowledge proofs thought that zkEVM was impossible. Therefore, they began to build a brand new zk virtual machine that was incompatible with EVM and had its own unique programming language and application tools. However, our team believed that Ethereum had already provided a very valuable consensus mechanism, and a large number of technical personnel in the community were already invested in establishing standards and developing deep tools, just as ConsenSys created MetaMask and Infura based on Ethereum.

However, creating an EVM-incompatible zk Rollup scaling solution cannot continue or expand the existing large network effect of EVM. Therefore, what our team wants to achieve is to widely apply zk technology in Rollup solutions based on EVM compatibility. Subsequently, the team spent about four years and finally launched what we consider to be the best-in-class and industry-leading solution, Linea.

Although from a certain perspective, Linea seems to have been "invisible" in the past few years, we have actually made many efforts in zk technology research and system development, including EVM compatibility. The team did not want to push immature solutions to the market. Therefore, when we advanced the project to what we now consider the "golden time" after four years of research and development, we officially made Linea available to the public, allowing people to start understanding and using this new solution.

5. ChainCatcher: The zk technology indeed requires a lot of specialized knowledge and more research time. Among the different proof generation algorithms, Linea chose zk-SNARK. Can you briefly explain the reason for choosing this technology?

Declan: In fact, the technology used by Linea is a bit more complex than zk-SNARKs, with slight differences from the original zk-SNARKs. Simply put, our proof system has inner proofs and outer proofs, with the outer proof being used for deployment on the Ethereum chain, and it is indeed a SNARK. The deployment process involves packaging the inner proof within the outer proof using a cryptographic library created by Linea's unique cryptography team, and finally deploying it to the Ethereum mainnet in the form of a SNARK.

The generation and compression of inner proofs were the main challenges the team tackled during four years of research. Linea has integrated research results into the prover Vortex—creating an extremely efficient proof generation tool through lattice-based cryptography and recursion. This method of generating proofs is gradually becoming popular in a broader ecosystem, and it is relatively cheaper compared to other solutions.

6. ChainCatcher: As we mentioned earlier, MetaMask and Infura are very important wallets and infrastructure in the Web3 ecosystem. What advantages does Linea, also backed by ConsenSys, have in the L2 zk Rollup competition?

Declan: I believe our advantages mainly lie in two aspects.

First, the technical achievements of Linea. We have discussed this in the previous questions. I want to emphasize that Vortex is a system that is quite advanced in zk, with extremely high efficiency and speed, which means its performance and the final user experience far exceed other tools. Low cost, high speed, and high throughput will provide users with a better experience, which is where Linea differentiates itself.

Therefore, I believe that over time, better technical solutions will ultimately stand the test of time. But as you mentioned, there are also issues related to the ecosystem. Linea has gained a more macro and comprehensive insight into the entire ecosystem from ConsenSys, understanding the entire process of user interactions on-chain, as well as the focus on user experience when interacting at the wallet layer and the underlying execution layer.

Linea truly values user experience and aims to differentiate itself from this perspective, which is also why we prepared for EVM compatibility from the very beginning. At the same time, we will leverage infrastructure and service providers that can bring in significant traffic. For example, the Linea Mainnet is directly built into the default dropdown menu of MetaMask, allowing users to connect without manually entering a new network. For a new network, being able to connect directly with high-traffic platforms like MetaMask and provide users with the possibility of "one-click access" will undoubtedly bring an unprecedented experience.

In summary, we are trying to meet the diverse needs of ecosystem builders and users from a compatibility perspective, thereby achieving their expectations for Linea's future.

How does Linea achieve decentralization?

7. ChainCatcher: Decentralization is one of the most important features of Ethereum and is also a concept that ConsenSys has always emphasized. However, many OP and zk Rollup projects in the ecosystem have sacrificed some decentralization in exchange for Ethereum's scalability, such as using centralized sequencers and centralized validation mechanisms. Some viewpoints argue that the components like sequencers and provers represent "narrow" decentralization. What is your view on this perspective?

Declan: My view is that the current Rollups architecture is relatively immature. We will set up some "Training wheels" as a means to protect users, and these Training wheels will be removed over time as the development of Rollups progresses and the technology stabilizes. But as you mentioned, these Training wheels may include centralized sequencers, a lack of fraud proofs and permission proofs, centralized zk Rollups provers, etc. At the same time, the upgrade of smart contracts from Layer1 to multi-signature has not yet achieved decentralization.

For most zk Rollups teams, especially for Linea, achieving the goal of decentralization is a gradual process—Linea has already released its progressive decentralization roadmap, which clearly describes how we will move from the current stage to a fully decentralized and trust-minimized system over time. Therefore, what Linea is undergoing is a journey toward decentralization. Although we have not yet reached the final destination, we have a clear plan and know how to get there. ConsenSys places great importance on the concept of "decentralization."

In addition, Linea has chosen to build a zkEVM, which means developers can directly deploy their projects on the Linea network. For Linea, there is no vendor lock-in mechanism. If a project wants to exit Linea at any time, there are no obstacles, and there is no need to rewrite smart contracts for other EVM-compatible networks. From this perspective, we already have a relatively high degree of decentralization in the zk Rollup track.

At the same time, Linea is currently in close contact with the infrastructure team at Infura. The Infura team has an execution layer client that has undergone years of testing on the Ethereum mainnet and has performed excellently. Linea is fortunate to collaborate with Infura to optimize transaction execution between layers. Therefore, we believe that Linea has the qualifications to achieve data decentralization, high throughput execution, and reduced transaction costs simultaneously. So we believe that this "narrow" decentralization dilemma is not a hindrance for Linea.

8. ChainCatcher: We also saw that the Linea official documents provided a decentralization roadmap. Is there a clear timeline for the subsequent stages mentioned?

Declan: Regarding the implementation of the roadmap, we are planning it in phases. Before reaching the final decentralization, Linea needs to go through five stages. So far, Linea has completed the Mainnet Alpha release and is currently in Phase 0. The next phase will be the open-source stack, which will allow the community to view and modify the code, helping to align the community with Linea's goals and achieve the vision of scalability and decentralization. Additionally, we need to achieve 100% coverage of all EVM code in the pre-compilation, which is also an important milestone for Linea to gain complete trust in zk. Subsequently, Linea needs to ensure that users can withdraw assets at the first opportunity, which is a very important anti-censorship property that Rollups can provide, and we need to ensure that this is fully realized before gradually decentralizing the operation nodes.

In the final stage, we will focus on "Multi-Prover." Multi-Prover allows a transaction or a batch of transactions to be implemented and verified by multiple different zkEVMs, which is a very exciting initiative because, with the support of Multi-Prover, even if there is an error in the implementation or verification process of one zkEVM, the system will continue to operate and maintain an almost elastic state. Just like in Ethereum Layer1, where elasticity is achieved through multiple execution and consensus nodes. Linea's current plan is to replicate these characteristics in Layer2 and ensure that we match the constraints in Ethereum's standards, references, and specifications to guarantee Linea's EVM compatibility.

Source: Linea Official Website Decentralization Roadmap

This is Linea's roadmap plan, which we have divided into five stages and prioritized the work that needs to be accomplished. However, it is difficult for us to predict the future and provide a specific timeline. Our current plan is to implement it as scheduled and continuously monitor the progress of this work and community feedback.

Linea Ecosystem Development Plan

9. ChainCatcher: Linea has grown rapidly, with TVL tripling just one week after launch. What are your expectations for Linea's future growth and development?

Declan: I think future growth is difficult to predict because we do not have a "crystal ball" to foresee the future. Much of the development actually relies on a broad ecosystem, and we are just a part of that ecosystem. Each component must work together to create an experience that can effectively solve user problems, thereby driving development in this field.

Today, whether it is developers looking to build applications or creators establishing new communities, everyone is striving to improve the ultimate user experience. These are all areas that Linea influences. One important area is the new paradigm of ERC-4337, which can bring account abstraction. Although account abstraction may lead to more intensive gas consumption in most cases, this will not deter those who want to adopt AA on Layer2 with lower transaction costs, which is one of Linea's advantages. Additionally, we hope to add a new terminal for account management and multi-signature control, which is also a key component in achieving account abstraction and smart contract accounts.

Therefore, Linea is working closely with other industry professionals to help Linea become an ideal Layer2 solution that provides a better user experience. These are all aspects that we can fully control, so we believe that by addressing these issues, we will see more positive activities from Linea in the future.

10. ChainCatcher: Although many projects have integrated Linea, there are still relatively few native projects. Will the future ecosystem focus on developing native projects? Are there any preferred tracks?

Declan: We are committed to promoting the development of Layer2 zk Rollup, which means we need to provide new solutions to user problems, and these will all become potential native use cases for Linea. During the integration process, we are also in discussions with many partners. Since Linea just released the Mainnet Alpha version and is in an upward phase, we are looking forward to seeing many native Linea projects and protocols, whether in DeFi, GameFi, or SocialFi, and I am very excited about it.

Currently, our focus is still on projects that have already been built on Ethereum or other blockchains, helping them integrate into the Linea network and find more product-market fit. At the same time, these mature projects can also help Linea build ecosystem modules and provide the necessary experience for integrating into Linea for other use cases.

11. ChainCatcher: Without a token issuance plan, how will Linea continue to attract more developers and users?

Declan: The platform has two aspects: developers and users. We hope to provide good support for both, thereby establishing network effects and starting a flywheel to bring more vitality to the Linea network.

What we can do for developers is to meet their existing needs and help them successfully build projects on the Linea network. This actually involves many angles, one of which is technical support. When a small project starts, we may provide support for them at hackathons, including funding and team collaboration, and then turn their project ideas into more practical and in-depth solutions, ultimately launching on the Linea mainnet.

At the same time, we will ensure that project parties can connect with other partners in the ecosystem and help improve their use cases. We have a new initiative called EIA, which stands for Ecosystem Investment Alliance. This is a way for Linea to help project parties connect with ConsenSys VC partners and other investors for funding support. Especially in a bear market, ensuring that potential projects are connected with funding support is particularly important. Additionally, we also provide some cooperative marketing opportunities to ensure that projects can gain visibility through Linea, ConsenSys, and other partners' distribution channels. We place great importance on the success of our partners while also valuing the concept of decentralization. Although I have been guiding this system within ConsenSys, we also hope that its future leadership belongs to the community.

On the user side, we have also stated at the recent EthCC that Linea has always placed a high priority on user experience. I believe this is the real difference between Linea and other systems at the user level. So far, Linea has achieved native integration with MetaMask, which serves as a trust foundation for new users joining Web3 and Linea. Linea will soon be able to realize all the functionalities of MetaMask. At the same time, we are also exploring how to attract users to use Layer2 solutions, including Linea, through account abstraction, and we are paying attention to execution layer issues, such as reducing transaction costs and shortening confirmation times. All of these will help bring users into the Linea ecosystem and create more network effects.

12. ChainCatcher: The Layer2 track is currently very crowded. From the perspective of the entire industry, is it necessary to have so many Layer2s? Is there a phenomenon of "reinventing the wheel"?

Declan: I believe that it is a good thing for the Layer2 zk Rollup ecosystem to be in a stage of continuous differentiation. Differentiation means we are exploring different solutions, and this is something that almost every emerging industry experiences. It is foreseeable that there will be more Layer2s and Layer3s.

In my view, over time, we may see the solutions that best address these issues eventually merge into one. However, I still believe that we are far from reaching a point where we can determine which approach is correct, as there are still some divergences in different market segments. Especially for Linea as a Layer2 zkEVM, we are truly focused on Ethereum scalability, building on the existing Ethereum network effect, and bringing more possibilities for stable developers and application depth. I believe this is the right path for the entire ecosystem or the Ethereum mainnet.

13. ChainCatcher: For zk Rollups, will the next innovation point be concentrated on the algorithm side or the application side?

Declan: Although zk originated in the mid-1980s, its application in the scalability of blockchain cryptographic systems is very unique and has great optimization space. Therefore, I believe that many innovative applications will occur every year, and I am glad that so many people are focusing on software innovations in zk. Before hardware acceleration, we need to keep our focus on software, such as promoting continuous innovation in Linea. We need to create a Ferrari first before we can keep accelerating. Linea's focus is precisely on building that Ferrari, and we are very close to success. At the same time, we also know that hardware acceleration is just one way to achieve an order-of-magnitude improvement in an established system.

In summary, I am not worried that Rollup solutions, including Linea, will become a bottleneck in the development process of zk technology, as new applications based on this technology will continuously emerge in the ecosystem.