Imagining Hybrid Rollups Advantages, Challenges, and Development Directions

Hybrid Rollups Advantages, Challenges, and Development Directions

Rollup, as a scalability solution, has significant potential in the scalability of public chains. However, it still faces some challenges, such as security, decentralization, user experience, and cost-effectiveness. By addressing these challenges and establishing a sound ecosystem and standardized support, Rollup is expected to achieve a wider range of applications and development, providing lasting support for the scalability of public chains.

Hybrid Rollup is a beneficial exploration to achieve this goal. Hybrid Rollup is an innovative concept that combines different architectures, draws on their strengths, and can better address the scalability and performance issues of public chains, while providing higher security and better user privacy protection.

This Bing Ventures article will explore the challenges faced by Rollup as a scalability solution from the perspective of public chain scalability, discussing issues such as security, decentralization, user experience, and cost-effectiveness, and based on this, explore possible solutions and prospects for the future of Rollup.

Challenges of Single Rollup

Zero-knowledge Rollup and Optimistic Rollup are currently the two mainstream Rollup architectures, but they each have obvious limitations. Optimistic Rollup takes up to 1 week for transactions to reach finality due to the need for fraud proofs, while Zero-knowledge Rollup faces higher costs due to the need for on-chain verification of validity proofs. The former has poor user experience, and the latter has poor cost-effectiveness and sustainability. Both also have varying degrees of trade-offs in terms of security and decentralization. For example, Optimistic Rollup carries the risk of operator fraud leading to exit scams, while most Zero-knowledge Rollups are centralized, with only a few operators able to submit transactions and validity proofs to L1, which increases audit risk.

Adopting a hybrid model of Optimistic Rollup and Zero-knowledge Rollup is expected to provide better trade-offs in terms of security and decentralization, improving overall system security while maintaining a certain degree of decentralization. This hybrid model also has the potential to provide the best possible experience for users and developers.

In addition, the widespread use of Rollup requires a healthy ecosystem that provides better tools and documentation for developers to build and deploy Rollup solutions. At the same time, the establishment of unified standards and specifications is also necessary to ensure interoperability and compatibility among different Rollup solutions.

Potential Advantages of Hybrid Rollup

As an emerging scalability solution, Hybrid Rollup is expected to bring improvements in the following areas:

Firstly, Hybrid Rollup offers greater flexibility and scalability. By building ZK circuits suitable for simple machines on L2, Hybrid Rollup can achieve the issuance of validity proofs based on Optimistic Rollup while avoiding the problem of frequent circuit updates, as the target machine architecture is fixed. This flexibility allows Hybrid Rollup to adapt to different application scenarios and requirements, and effectively scale to handle large-scale transactions.

Secondly, Hybrid Rollup combines the advantages of Optimistic Rollup and Zero-Knowledge Proofs, providing higher security. Optimistic Rollup offers high performance and low-cost transaction processing, but carries certain risks as verification is performed after transaction submission. On the other hand, Zero-Knowledge Proofs ensure transaction validity and privacy, making it difficult for attackers to tamper with or steal user assets. By combining these two mechanisms, Hybrid Rollup can provide stronger security.

In addition, Hybrid Rollup can reduce the need for trust. By using Zero-Knowledge Proofs to prove the correct execution of transactions, Hybrid Rollup can reduce the reliance of users on the honesty of validation nodes. Users only need to trust the correctness of the ZK circuit, without the need to trust the honesty of the validation nodes, thereby reducing their trust requirements.

Technical Implementation Challenges of Hybrid Rollup

As an emerging scaling solution, Hybrid Rollup faces some technical implementation challenges. Here are two main challenges:

Firstly, the process of compiling the execution layer into a simplified virtual machine may require complex engineering and research. This process needs to ensure that the compiled code can be executed correctly on the simplified virtual machine and remains consistent with the original execution layer. To address this challenge, a series of technical issues such as compiler optimization, virtual machine architecture, and compatibility need to be addressed. Only when these issues are properly resolved can the advantages of flexibility and scalability of Hybrid Rollup be realized.

Secondly, the implementation of zk-rollups may require dealing with a large amount of data and computation, which brings challenges to performance and scalability. Hybrid Rollup uses Zero-Knowledge Proofs to verify the correctness of execution traces, which requires the generation and verification of a large amount of proof data. To ensure the real-time generation and verification of these zk-rollups in actual networks, optimization of proof generation algorithms and verification algorithms is needed to improve their efficiency and scalability.

Given these challenges, at the current stage of technology, Hybrid Rollup is more suitable for specific application scenarios and needs. Here are two main application scenarios that the author believes are more suitable:

  • Firstly, large-scale transaction processing. Due to the method of compiling the execution layer into a simplified virtual machine, Hybrid Rollup provides higher flexibility and scalability, making it more suitable for handling large-scale transactions. It can effectively batch process a large number of transactions and achieve low-latency transaction confirmation, thus meeting the needs of large-scale transaction processing.

  • Secondly, applications with a high focus on privacy. Hybrid Rollup adopts Zero-Knowledge Proofs to verify execution traces, thereby protecting the privacy of transactions. The detailed content of the transactions can be proven correct, but the actual transaction data can be kept confidential and only accessible to participating validation nodes. This privacy protection mechanism makes Hybrid Rollup more suitable for application scenarios with a high demand for privacy protection, such as financial transactions or personal identity verification.

In summary, the hybrid Rollup model faces implementation challenges such as compiling execution layers into simplified virtual machines and implementing traceable zero-knowledge proofs. However, in scenarios involving large-scale transaction processing and high privacy concerns, the hybrid Rollup model demonstrates its advantages and suitability. By addressing technical challenges and meeting specific needs, hybrid Rollup is expected to play an important role in the field of scalability.

Future Development Directions of Rollup

The hybrid Rollup is considered to be the future development direction of Rollup, but its further maturity must be based on the further development of the following single Rollup technologies:

Firstly, the optimistic Rollup model. Optimistic Rollup provides higher transaction throughput and lower costs by further optimizing and improving the mechanism of optimistic confirmation (finality). This may involve innovations in more efficient state management, transaction submission, and dispute resolution mechanisms. The optimistic Rollup model has the potential to surpass hybrid Rollup in terms of performance and cost.

Secondly, the zero-knowledge proof Rollup model. With the development of zero-knowledge proof technology, more efficient and faster verification processes can be achieved, thereby improving the performance and scalability of zero-knowledge proof Rollup, including innovations in more efficient proof construction, compact proof size, and faster verification algorithms. The zero-knowledge proof Rollup model is expected to surpass hybrid Rollup in terms of verification efficiency and performance.

We believe that the introduction of hybrid Rollup will promote more projects and developers to participate in building the Rollup ecosystem. By providing flexibility and scalability, hybrid Rollup provides more opportunities for various application scenarios and industries. For example, the DeFi field can leverage the high performance and low cost advantages of hybrid Rollup to build more complex financial protocols and smart contracts. The following are several directions that we are optimistic about:

  1. Cross-chain interoperability: Hybrid Rollup can provide cross-chain interoperability solutions for different public chains. By using hybrid Rollup as a bridging layer, various public chains can achieve secure and efficient asset transfers and information transmission. This will promote collaboration and value flow between multiple chains, breaking down existing barriers between chains. Interoperability between Ethereum and other public chains is a potential opportunity, and hybrid Rollup can realize seamless interaction and composition of assets on both chains on a larger scale.

  2. Industry compliance and privacy protection: The combination of hybrid Rollup’s features can provide solutions for industry compliance and privacy protection. By adopting zero-knowledge proof technology, hybrid Rollup can ensure transaction privacy and provide verifiable transaction execution. This is particularly important for areas such as RWA and institutional users that have a high demand for privacy protection.

  3. Community governance and consensus mechanism innovation: The development of hybrid Rollup will encourage more community governance and consensus mechanism innovation. By introducing hybrid Rollup, public chain communities can achieve higher transaction throughput and lower costs while maintaining a high degree of decentralization and security. This may lead to experiments and improvements in public chain governance and consensus mechanisms to meet the needs of different DAOs.

  4. Infrastructure and development tool support: With the development of hybrid Rollup, it is expected that more infrastructure and development tool support will emerge. Developers can build tools and platforms for deploying and managing hybrid Rollup, simplifying the development process and providing a better user experience. This will further promote the adoption of hybrid Rollup and provide more opportunities and resources for developers.

In summary, Hybrid Rollup is expected to bring positive trends in ecosystem scalability, cross-chain interoperability, industry compliance and privacy protection, community governance and consensus mechanism innovation, as well as infrastructure and development tool support. With the continuous development of technology and applications, Hybrid Rollup will further enhance the scalability and practicality of L1 and L2.