Author: LINDABELL
At the recent Devcon conference, Ethereum Foundation core member Justin Drake proposed the Beam Chain proposal, planning 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 drawn 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 freeing itself from reliance on traditional smart contract logic.
Driven by this trend, projects such as RISC Zero, Succinct, and Cysic are seen as important players in promoting innovation in this field. Among them, RISC Zero, with its RISC-V architecture-based zkVM, has developed a series of open-source tools like Zeth, Kailua, and Bonsai, which not only enhance block verification and Rollup performance but also provide technical support for Ethereum's ZK upgrade.
RISC zkVM ecosystem product matrix: from core technology to application scenarios.
RISC Zero is a zkVM implementation based on the RISC-V instruction set architecture, serving as a general-purpose zero-knowledge computing platform that supports multiple mainstream programming languages such as Rust and C++, capable of running almost any computational task. Compared to other zero-knowledge technology platforms, RISC Zero's provers and verifiers are completely open-source, allowing developers to generate and verify proofs locally. Furthermore, RISC Zero's verifiers are compatible with multiple platforms, adapting to different blockchain ecosystems, simplifying the development process of decentralized applications.
In June of this year, RISC Zero released zkVM 1.0. zkVM 1.0 not only supports multiple languages and complex computational tasks but also utilizes Continuations technology to break large-scale computations into smaller segments, achieving efficient parallel computation and verification. According to the roadmap, RISC Zero plans to achieve a 20-fold improvement in zkVM performance and cost by the end of 2024, with optimization efforts including fully migrating the proof process to GPUs (80% completed), introducing new RISC-V v2 circuit designs, and conducting specialized optimizations for recursive circuits. Meanwhile, RISC Zero is integrating a series of acceleration modules for algorithms such as RSA, Keccak, and ECDSA to enhance 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 example, through the Bonsai network, developers can generate zero-knowledge proofs without dedicated hardware; the Steel tool allows complex EVM computations to be moved to an off-chain environment while maintaining verifiable results, thus reducing on-chain execution costs; and Blobstream Zero bridges Celestia's data availability layer, providing more possibilities for data sharing and verification in the modular blockchain ecosystem.
Zeth: Proving that the entire Ethereum block was constructed correctly.
Zeth is an open-source Ethereum zero-knowledge block prover developed by RISC Zero based on its zkVM technology, capable of verifying the validity of Ethereum blocks through zero-knowledge proofs without relying on traditional verifiers or sync committees. RISC Zero defines Zeth as a Type-0 zkEVM, fully compatible with the Ethereum protocol while enhancing development efficiency through code reuse.
Ethereum co-founder Vitalik Buterin, in his article 'Different types of zk-EVMs,' classified zkEVMs into four types, where Type-1 strives for complete and uncompromising equivalence to Ethereum; Type-2 aims for full equivalence to EVM, but not complete equivalence to Ethereum; Type-3 is nearly equivalent to 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 minutes. Testing data shows that Zeth can generate block proofs at a speed of 1.1 MHz and expand GPU clusters through the 'continuations' feature, increasing the speed to 4.7 MHz to 6.3 MHz. This performance optimization also reduces the cost of proof generation. According to tests, the proof generation cost for a block containing 182 transactions is only $21.72, with a cost of about $0.11 per transaction.
At the same time, during the development process of Zeth, the RISC Zero team fully utilized components from the Rust ecosystem, such as revm, ethers, and alloy, allowing developers to quickly implement block proof functionality and apply it to different scenarios. This design provides developers with more flexibility to adjust block construction logic as needed and adapt to future Ethereum improvement proposals.
At the application level, Zeth provides efficient solutions for zk Rollup, light clients, and cross-chain bridges. The construction of traditional zk Rollup and zkEVM requires significant time and funding, which deters smaller teams. Zeth, based on a modular zkVM architecture, allows developers to easily customize block verification logic. For example:
zk Rollup: Zeth can quickly achieve block proofs, shortening the development cycle of ZK Rollup and reducing funding input.
Light Client: Verifying block validity without rebuilding the block, reducing operational costs.
Cross-Chain Bridge: Zeth can verify the correctness of cross-chain data without leaking sensitive on-chain information through ZKP, reducing reliance on third-party trust and lowering the risk of cross-chain attacks.
In May of this year, Zeth successfully expanded to support the extraction of Optimism block data from the Ethereum mainnet and generate ZKP to verify block correctness, also supporting on-chain verification. In other words, with Zeth, Optimism can verify transactions more efficiently and resolve transaction disputes.
Bonsai: Allows developers to generate proofs without using their own hardware.
Bonsai is a remote proof service specifically designed for zkVM applications, allowing developers to generate proofs without using their own hardware, thus addressing the contradiction between limited on-chain computing resources and high costs. Through Bonsai, developers only need to define the zkVM applications to be executed and input data, and Bonsai can run computations in the background and generate corresponding zero-knowledge proofs. This process completely eliminates the need for developers to deploy additional hardware. Furthermore, Bonsai utilizes a large number of GPU clusters to support parallel processing of multiple computation tasks. Additionally, Bonsai provides simple and easy-to-use API and SDK interfaces, enabling developers to easily integrate it into existing systems, further reducing development difficulty.
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 transfer amount through Bonsai Pay. Bob can then log into Bonsai Pay, input his email address, and complete Google account authentication. Bonsai Pay will use OAuth 2.0 to generate an authorization token, proving that Bob is indeed the holder of that email. Subsequently, Bonsai Pay calls the Bonsai proof service to generate a zero-knowledge proof, demonstrating that Bob's Google account is associated with his wallet address. After the smart contract verifies the proof, it will unlock the funds and transfer them to Bob's wallet address.
Throughout this process, Bonsai Pay uses ZKP technology to verify the fact that 'Bob's Google account is associated with his wallet address,' while avoiding the disclosure of any specific information about the Google account.
Another important application of Bonsai is the Bonsai ZK co-processor (ZK Co-processor). It transfers complex computational tasks off-chain through zero-knowledge proof technology, generating immutable proofs to ensure the correctness of results. Additionally, the deployment of the Bonsai co-processor is straightforward; developers only need to write a zkVM application to handle logic and call Bonsai through a simple Solidity contract to run computations and verify results. Throughout this process, the Bonsai proof service is responsible for generating zero-knowledge proofs of off-chain computations, which can be verified on-chain.
Bonsai ZK co-processor is suitable for on-chain applications that require high performance and low cost. For example, in DAO governance, it can move complex voting calculations off-chain, significantly reducing on-chain gas fees. The Bonsai DAO Governor has reduced the gas cost per vote by over 50% through the co-processor, effectively improving governance efficiency and lowering participation barriers.
Boundless: A verifiable computation layer.
In traditional blockchain architectures, to ensure the validity of transactions, all nodes need to repeat the computation for every transaction. This 'global re-execution' mode, while ensuring security and consistency, also incurs extremely high computational costs. To address this issue, RISC Zero introduced Boundless, allowing a single node to complete the computation and generate a verifiable zero-knowledge proof, enabling other nodes to confirm the results by verifying the proof without repeating computations.
Boundless simplifies the verification process through recursive composition technology. It merges multiple small zero-knowledge proofs into a single overall proof, allowing verifiers to check just one total proof instead of verifying all stage proofs one by one. To further optimize the generation efficiency of zero-knowledge proofs, Boundless incorporates dedicated cryptographic acceleration circuits, enhancing the efficiency of common tasks like hash computation and digital signature verification.
Additionally, 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. They can quickly build and deploy zero-knowledge applications on any blockchain using the proving services provided by Boundless without having to migrate existing systems or update verification contracts.
Blobstream Zero: A cross-chain bridge of zkVM that simplifies cross-chain data verification.
Blobstream Zero is a cross-chain bridge based on zkVM launched by RISC Zero in collaboration with Celestia, designed to seamlessly connect Celestia's data availability layer to existing modular blockchain ecosystems. By sharing and verifying data on Celestia, Blobstream Zero facilitates more convenient data transfer and verification between chains.
As a completely open-source public product, Blobstream Zero allows any project or developer to run local instances and generate zero-knowledge proofs. Additionally, Blobstream Zero can support ZK co-processors. ZK co-processors are essentially off-chain computing tools, hence they require reliable data to perform computations. Blobstream Zero can obtain data from blockchains like Celestia and can prove the reliability of the transmitted data by generating ZK proofs.
Steel: A new paradigm of smart contracts with off-chain execution and on-chain verification.
Steel is an open-source tool launched by RISC Zero that utilizes zkVM technology to achieve verifiable smart contract execution off-chain. With Steel, developers can transfer EVM operations from on-chain execution to off-chain execution, while generating zero-knowledge proofs to ensure the authenticity and verifiability of computation results.
Traditional smart contracts need to fully execute all logic on-chain, incurring high gas costs and limiting the development of complex applications. Steel's off-chain computation and on-chain verification mechanism addresses this issue. For example, in a simple smart contract, determining whether an account's ERC20 balance is greater than 1 and incrementing a counter variable. The traditional method requires full on-chain execution of logic, while Steel performs the computation off-chain and generates a zero-knowledge proof, requiring only the proof to be verified on-chain without repeating the contract logic.
Currently, RISC Zero has released Steel 1.0, and partners have successfully used this tool to develop applications. For example, in a contract call processing approximately 400,000 SLOAD operations, Steel transferred the computation off-chain, and then verified the generated zero-knowledge proofs on-chain. The proof generation cost was less than $10, and the on-chain verification cost was below 300,000 gas.
Kailua: A hybrid ZK solution promoting innovation in Rollup architecture.
Following the release of Zeth, RISC Zero launched Kailua, aiming to provide a hybrid ZK Rollup upgrade solution for optimistic Rollups. Traditional optimistic Rollups usually require a 7-day challenge period, leading to slow transaction finality, while ZK Rollups can achieve finality quickly but incur high costs for continuously generating zero-knowledge proofs. Kailua combines the advantages of both, achieving a balance between cost and efficiency through a hybrid architecture. As an extension of the Optimism Kona framework, Kailua not only supports unmodified Kona running on zkVM but also introduces an innovative dispute resolution mechanism that reduces staking requirements and minimizes finality delays, thereby enhancing system efficiency and usability.
In Kailua's architecture, the dispute mechanism adopts a completely new design. First, its dispute resolution mechanism removes the time limit, allowing verifiers ample time to generate proofs in cases of network interruptions or other special circumstances, thus enhancing the system's resilience. Even in extreme cases, RISC Zero's zkVM's scalable architecture can complete proofs within one hour. Additionally, Kailua's on-demand verification feature allows developers to flexibly configure verification frequency, enabling a gradual transition to fully verified Rollup mode at lower costs.
Unlike ZK Rollups, Kailua's design does not require continuous proof generation. For low-frequency empty blocks or Rollups with special contract needs, Kailua offers a more cost-effective choice. At the same time, Kailua significantly reduces the staking cost requirements for Rollups. The staking amount for traditional optimistic Rollups increases linearly with longer finality periods, while Kailua's optimized design stabilizes staking requirements, allowing the system to maintain security and activity at a lower cost even over long periods.
Currently, Kailua is fully open-source. Developers can use its command-line tools to deploy a local Optimism test network and quickly upgrade to a network that supports ZK fault proofs. Kailua also supports simulating fault proposals, helping developers understand how verifiers challenge incorrect states through zkVM, thereby gaining a deeper understanding of its dispute resolution mechanism. In the future, Kailua will further optimize costs and performance and expand support for more Rollup frameworks.
Summary
As can be seen from the above, RISC Zero's zkVM product matrix is driving the development of zero-knowledge proof technology in multiple fields. Zeth and Kailua focus on optimizing Rollup architecture, improving block verification efficiency and dispute resolution speed. Bonsai provides remote proof services, reducing hardware dependence and operational costs, enabling developers to build applications more efficiently. Blobstream Zero offers reliable support for the modular blockchain ecosystem by efficiently verifying cross-chain data. Additionally, Steel reduces the gas cost of smart contract execution through an off-chain computation and on-chain verification model.
Of course, while continuously improving the zkVM product matrix, RISC Zero is also pushing for innovation in the underlying technology of zkVM. Recently, RISC Zero zkVM released version 1.2, introducing a new pre-compilation method that allows developers to deploy pre-compilation logic alongside their applications without having to embed it within zkVM itself. This means developers can add new pre-compilation logic without modifying on-chain verification contracts or coordinating the configuration of provers, nor do they need to fork or make major changes to zkVM to achieve performance optimization. Additionally, by defining application-specific pre-compilations, the computational cost of proof generation can be reduced. For example, after integrating RSA pre-compilation, Automata reduced its execution cycle from 39 million to 217,000, lowering costs by about 180 times.
As zkVM technology continues to optimize, its development potential will gradually be realized across multiple application scenarios. However, to better unlock this potential, it still relies on ecosystem collaboration and the practical performance of technology implementation.
