At the recent Devcon conference, Justin Drake, a core member of the Ethereum Foundation, introduced the Beam Chain proposal, aiming to upgrade Ethereum’s consensus layer through zkSNARK and zkVM technologies to enhance the network’s scalability, security, and efficiency. This vision has once again brought attention to the importance of zkVM. As a general-purpose zero-knowledge virtual machine, zkVM can handle complex computations in a more flexible and efficient manner, while eliminating the reliance on traditional smart contract logic.

Driven by this trend, projects like RISC Zero, Succinct, and Cysic are seen as key players in driving innovation in this field. Among them, RISC Zero, with its zkVM based on the RISC-V architecture, has developed a series of open-source tools, including Zeth, Kailua, and Bonsai. These tools not only improve blockchain validation and rollup performance but also provide technical support for Ethereum’s ZK upgrade.

RISC zkVM Ecosystem Product Matrix: From Core Technology to Scenario Applications

RISC Zero is a zkVM implementation based on the RISC-V instruction set architecture. As a general-purpose zero-knowledge computing platform, it supports multiple mainstream programming languages, such as Rust and C++, and can run almost any computational task. Compared to other zero-knowledge technology platforms, RISC Zero’s provers and verifiers are fully open-source, allowing developers to generate and verify proofs locally. Additionally, RISC Zero’s verifier is compatible with multiple platforms, adapting to various blockchain ecosystems and simplifying the development process for decentralized applications.

In June this year, RISC Zero released zkVM 1.0. This version not only supports multiple languages and complex computational tasks but also uses Continuations technology to split large-scale computations into smaller segments, enabling efficient parallel computation and verification. According to the roadmap, RISC Zero plans to achieve a 20x improvement in zkVM performance and cost by the end of 2024. Optimizations include migrating the proof process entirely to GPUs (80% completed), introducing new RISC-V v2 circuit designs, and performing targeted optimizations for recursive circuits. At the same time, RISC Zero is integrating a series of acceleration modules for algorithms like RSA, Keccak, and ECDSA to improve the performance of Ethereum-related tasks and cryptographic operations.

Around the core capabilities of zkVM, RISC Zero has also developed a series of open-source tools and products. For instance, with the Bonsai network, developers can generate zero-knowledge proofs without dedicated hardware; the Steel tool allows for moving complex EVM computations to off-chain environments while maintaining verifiable results, thus reducing on-chain execution costs; and Blobstream Zero bridges the Celestia data availability layer, offering more possibilities for data sharing and validation within the modular blockchain ecosystem.

Zeth: Proving the Correct Construction of Entire Ethereum Blocks

Zeth, an open-source Ethereum zero-knowledge block prover developed by RISC Zero based on its zkVM technology, can validate the validity of Ethereum blocks through zero-knowledge proofs without relying on traditional validators or synchronization committees. RISC Zero defines Zeth as a Type-0 zkEVM, which is fully compatible with the Ethereum protocol and improves development efficiency through code reuse.

In his article “Different Types of zk-EVMs,” Ethereum co-founder Vitalik Buterin categorized zkEVMs into four types: Type-1 aims for complete and uncompromising equivalence with Ethereum; Type-2 seeks full equivalence with the EVM but not with Ethereum as a whole; Type-3 is almost equivalent to the EVM; and Type-4 is completely incompatible with Ethereum.

Thanks to the high performance of RISC Zero’s zkVM, Zeth can complete Ethereum block verification in just a few minutes. Test data shows that Zeth can generate block proofs at a speed of 1.1 MHz, and by leveraging the “continuations” feature to expand GPU clusters, the speed can be boosted to between 4.7 MHz and 6.3 MHz. This performance optimization also reduces the cost of proof generation. According to tests, the cost of generating a proof for a block containing 182 transactions is only $21.72, with the cost per transaction around $0.11.

In developing Zeth, the RISC Zero team made full use of components from the Rust ecosystem, such as revm, ethers, and alloy, allowing developers to quickly implement block proof functionality and apply it in various scenarios. This design provides developers with more flexibility, enabling them to adjust block construction logic and adapt to future Ethereum improvement proposals.

On the application layer, Zeth offers efficient solutions for zk Rollups, light clients, and cross-chain bridges. Traditional zk Rollups and zkEVM construction require significant time and funding, which can deter small teams. However, Zeth, based on its modular zkVM architecture, allows developers to easily customize block verification logic. For example:

• zk Rollup: Zeth enables quick block proof generation, shortening development cycles and reducing funding requirements for zk Rollups.
• Light Clients: Zeth allows block validity verification without needing to rebuild the block, thus lowering operational costs.
• Cross-Chain Bridges: Zeth uses ZKP to verify cross-chain data correctness without leaking sensitive on-chain information, reducing reliance on third-party trust and minimizing cross-chain attack risks.

In May of this year, Zeth successfully expanded to support extracting Optimism block data from the Ethereum mainnet and generating ZKPs to verify block correctness, also supporting on-chain verification. This means that with Zeth, Optimism can verify transactions more efficiently and resolve transaction disputes.

Bonsai: Enabling Developers to Generate Proofs Without Using Their Own Hardware

Bonsai is a remote proof service designed specifically for zkVM applications, allowing developers to generate proofs without using their own hardware, thus solving the dilemma of limited on-chain computing resources and high costs. With Bonsai, developers only need to define the zkVM application and input data to be executed, and Bonsai will handle the computation in the background and generate the corresponding zero-knowledge proofs. This process requires no additional hardware deployment from the developers. Additionally, Bonsai leverages a large GPU cluster to support parallel processing of multiple computational tasks. Moreover, Bonsai provides simple-to-use APIs and SDK interfaces, enabling developers to easily integrate it into existing systems, further reducing development complexity.

Based on this remote proof service, RISC Zero launched the open-source tool Bonsai Pay, which combines OAuth2.0 authentication and ZKP technology, allowing users to send or receive tokens on the Ethereum network using their Google accounts. For example, when Alice wants to transfer funds to Bob, she can input Bob’s Google email and the transfer amount through Bonsai Pay. Bob then logs into Bonsai Pay and inputs his email address to complete the Google account authentication. Bonsai Pay uses OAuth 2.0 to generate an authorization token, proving that Bob is indeed the owner of that email address. Bonsai Pay then calls the Bonsai proof service to generate a zero-knowledge proof, demonstrating that Bob’s Google account is linked to his wallet address. After the smart contract verifies the proof, it unlocks the funds and transfers them to Bob’s wallet address.

Throughout this process, Bonsai Pay uses ZKP technology to verify the fact that “Bob’s Google account is linked to his wallet address” while avoiding any leakage of specific Google account information.

Another important application of Bonsai is the Bonsai ZK co-processor (ZK Co-processor). It uses zero-knowledge proof technology to transfer complex computing tasks from the chain to the off-chain, and generates tamper-proof proofs to ensure the correctness of the results. At the same time, the deployment of Bonsai coprocessor is also very simple. Developers only need to write a zkVM application to process the logic, and call Bonsai through a simple Solidity contract to run the calculation and verify the results. Throughout the process, the Bonsai Proof Service is responsible for generating off-chain zero-knowledge proofs that can be verified on-chain.

The Bonsai ZK Co-processor is suitable for on-chain applications that require high performance and low costs. For example, in DAO governance, it can move complex voting computations off-chain, significantly reducing on-chain Gas fees. Bonsai DAO Governor, through the co-processor, reduces the Gas cost per vote by over 50%, effectively improving governance efficiency and lowering the participation threshold.

Boundless: Verifiable Computation Layer

In traditional blockchain architectures, to ensure the validity of transactions, every node must redundantly execute all the computations for each transaction. While this “global re-execution” model ensures security and consistency, it also results in extremely high computational costs. To address this issue, RISC Zero introduced Boundless, which allows a single node to complete the computation and generate a verifiable zero-knowledge proof. Other nodes only need to verify the proof to confirm the result, eliminating the need to re-execute the computation.

Boundless simplifies the verification process through recursive composition technology. It combines multiple small zero-knowledge proofs into a single overall proof, so that verifiers only need to check one total proof, rather than verifying each proof from all stages individually. To further optimize the efficiency of zero-knowledge proof generation, Boundless includes specialized cryptographic acceleration circuits, enhancing the efficiency of common tasks like hash computation and digital signature verification.

Moreover, developers using Boundless do not need to deeply understand zero-knowledge technology. They can simply write applications using familiar programming languages, such as Rust or Solidity. Currently, Boundless is open for free access to developers, enabling them to quickly build and deploy zero-knowledge applications on any blockchain without migrating existing systems or updating verification contracts.

Blobstream Zero: zkVM-based Cross-Chain Bridge for Simplified Cross-Chain Data Validation

Blobstream Zero is a zkVM-based cross-chain bridge launched by RISC Zero in collaboration with Celestia, designed to seamlessly connect Celestia’s data availability layer to the existing modular blockchain ecosystem. By sharing and validating data on Celestia, Blobstream Zero facilitates more convenient data transfer and validation between blockchains.

As a fully open-source public product, Blobstream Zero allows any project or developer to run a local instance and generate zero-knowledge proofs. Additionally, Blobstream Zero supports ZK co-processors. A ZK co-processor is essentially an off-chain computation tool that requires reliable data to perform computations. Blobstream Zero can retrieve data from blockchains such as Celestia and, by generating ZK proofs, can verify the reliability of the transmitted data.

Steel: A New Paradigm for Off-Chain Execution and On-Chain Verification of Smart Contracts

Steel is an open-source tool launched by RISC Zero that uses zkVM technology to enable off-chain verifiable execution of smart contracts. With Steel, developers can offload EVM operations from the chain to off-chain execution, while generating zero-knowledge proofs to ensure the authenticity and verifiability of the computation results.

Traditional smart contracts require the entire logic to be executed on-chain, leading to high Gas costs and limiting the development of complex applications. Steel’s off-chain computation and on-chain verification mechanism address this issue. For example, in a simple smart contract that checks if an account’s ERC20 balance is greater than 1 and increments a counter variable, traditional methods require the logic to be fully executed on-chain. However, with Steel, the computation is performed off-chain, and a zero-knowledge proof is generated. The on-chain process only requires proof verification, eliminating the need to re-execute the contract logic.

Currently, RISC Zero has released Steel 1.0, and several partners have already used the tool to develop applications. For example, in a contract call processing approximately 400,000 SLOAD operations, Steel offloaded the computation to off-chain execution and then verified the generated zero-knowledge proof on-chain. The proof generation cost was under $10, and the on-chain verification cost was less than 300,000 Gas.

Kailua: A Hybrid ZK Solution Driving Rollup Architecture Innovation

After the release of Zeth, RISC Zero introduced Kailua, providing an upgrade solution for optimistic Rollups through a hybrid ZK Rollup approach. Traditional optimistic Rollups typically require a 7-day challenge period, which results in slower transaction finality. While ZK Rollups achieve faster finality, the continuous generation of zero-knowledge proofs incurs high costs. Kailua combines the benefits of both approaches, balancing cost and efficiency through a hybrid architecture. As an extension of the Optimism Kona framework, Kailua supports unmodified Kona running on zkVM and introduces an innovative dispute resolution mechanism that reduces staking requirements and minimizes finality delays, thereby improving system efficiency and usability.

In Kailua’s architecture, the dispute resolution mechanism adopts a new design. First, the mechanism removes time constraints, allowing validators ample time to generate proofs in the event of network disruptions or other special circumstances, enhancing the system’s resilience. Even in extreme cases, RISC Zero zkVM’s scalable architecture can generate proofs within an hour. Additionally, Kailua’s on-demand validation feature enables developers to flexibly configure validation frequency, making a gradual transition to full validation Rollup modes at a lower cost.

Unlike ZK Rollups, Kailua’s design doesn’t require continuous proof generation. For low-frequency empty blocks or Rollups with special contract needs, Kailua offers a more cost-effective alternative. Kailua also significantly reduces staking costs for Rollups. While traditional optimistic Rollups increase staking requirements linearly as the finality period lengthens, Kailua’s optimized design fixes the staking demand, maintaining security and activity at lower costs even over longer periods.

Currently, Kailua is fully open source. Developers can use its command-line tools to deploy local Optimism testnets and quickly upgrade to networks supporting ZK fault proofs. Kailua also supports simulating fault proposals, allowing developers to understand how validators challenge erroneous states via zkVM, providing deeper insights into the dispute resolution mechanism. In the future, Kailua will further optimize cost and performance, and extend support to more Rollup frameworks.

Summary

As seen from the above, RISC Zero’s zkVM product suite is driving the development of zero-knowledge proof technology across various fields. Zeth and Kailua focus on optimizing Rollup architecture, improving block verification efficiency and dispute resolution speed. Bonsai provides remote proof services, reducing hardware dependencies and operational costs, enabling developers to build applications more efficiently. Blobstream Zero offers efficient cross-chain data verification, providing reliable support for modular blockchain ecosystems. Additionally, Steel reduces Gas costs for smart contract execution through its off-chain computation and on-chain validation model.

Of course, while continuously improving the zkVM product suite, RISC Zero is also advancing innovations in zkVM’s underlying technology. Recently, the RISC Zero zkVM 1.2 version was released, introducing a new precompilation method that allows developers to deploy precompiled logic alongside applications, without needing it to be built into the zkVM itself. This means developers can add new precompiled logic without modifying on-chain verification contracts, coordinating with proof generators, or making major changes to the zkVM to achieve performance optimizations. Furthermore, by defining precompiles through applications, the computational cost of proof generation can be reduced. For example, after integrating the RSA precompile, Automata reduced the execution cycle from 39 million to 217,000, cutting costs by about 180 times.

With ongoing optimization of zkVM technology, its potential will gradually manifest across multiple application scenarios. However, to fully unleash this potential, ecosystem collaboration and the actual performance of technology deployment remain crucial.

Disclaimer:

1. This article is reprinted from [ChainFeeds Research)]. All copyrights belong to the original author [@chainfeeds">Linda Bell]. If there are objections to this reprint, please contact the Gate Learn team, and they will handle it promptly.
2. Liability Disclaimer: The views and opinions expressed in this article are solely those of the author and do not constitute investment advice.
3. The Gate Learn team translated the article into other languages. Copying, distributing, or plagiarizing the translated articles is prohibited unless mentioned.