zkRouter: A New Cross Chain Infrastructure

Blockchain technology has seen significant progress in recent years with the emergence of new technologies and applications. One crucial advancement in this field is the creation of cross-chain bridges, which play a critical role in linking different blockchain ecosystems and enabling cross-chain interoperability. However, the past two years have witnessed several security breaches in certain cross-chain bridges, resulting in substantial losses of assets for users, project developers, and other stakeholders in the ecosystem. These incidents have led to a growing concern among the blockchain community about the vulnerabilities of cross-chain bridges.

The ability for assets and information to be transferred between different blockchain networks is essential for advancing and expanding the blockchain ecosystem. However, current cross-chain solutions face a common issue in that they rely on trust mechanisms which can be unreliable and open to malicious attacks

• LayerZero requires trust in oracle and relay to prevent collusion and malicious attacks
• cBridge needs confidence in the majority of validators to ensure the secure storage of private keys
• Nomad assumes that validators will not act maliciously
• Cosmos IBC / Polkadot XCMP needs trust in the public blockchain infrastructure to be secure

Recent security incidents involving cross-chain bridges have demonstrated the problem of relying on trust mechanisms in these solutions. Recent breaches show that this reliance on trust is the fundamental cause of these security issues. This type of trust assumption conflicts with the decentralized principles of blockchain. As a result, cross-chain bridges have become a weak point in the blockchain ecosystem, susceptible to security attacks which can result in significant losses of digital assets and hinder the progress of blockchain practitioners in the industry.

The data recorded on a blockchain represents the consensus state of that particular chain. The block header hash of the chain represents the consensus state, and the hash can uniquely identify the data stored in a block. The main challenge in cross-chain transfers is to securely and reliably transfer the consensus state in a decentralized manner. Current solutions rely on specific trust facilities, which only partially achieve decentralization and can introduce vulnerabilities in the cross-chain ecosystem. Recent attacks on cross-chain bridges have highlighted the need for secure cross-chain solutions.

A new solution that was introduced is zkRouter. Multichain recently introduced a trustless, general cross-chain infrastructure based on zero-knowledge proof (ZKP) technology. Multichain is a leading provider of a cross-chain bridge and general message cross-chain services. Multichain has successfully connected 81 public chains with over 800,000 users. They have succeeded greatly with products such as Router, anyCall and NFT Router.

zkRouter utilizes ZKP technology to securely and efficiently connect multiple blockchain networks and achieve seamless interoperability. This innovation is extremely valuable for cross-chain interoperability as it allows for transferring assets and information between different blockchains in a trustless, secure and privacy-friendly manner without revealing sensitive information. Most cross-chain bridges still rely on centralized mechanisms to transmit cross-chain information. ZKP can eliminate this need for trust, which is why Multichain is using this mechanism to build a new generation of cross-chain interoperability protocols.

Advantages

The implementation of ZKP technology in zkRouter offers several advantages for cross-chain interoperability:

1. Trustlessness: zkRouter utilizes zk-SNARKs to prove cross-chain communication messages without introducing external trust assumptions. As long as there is an honest node in the relay network, the security of the zkRouter cross-chain can be guaranteed, given the safety of the underlying public chain and consensus mechanism.
2. Scalability and Efficiency: zkRouter enables more dApps to run on it. Its lightweight on-chain computing allows many transactions to run concurrently with low latency, reducing chain fees.
3. Low Threshold and Decentralization: Node operators on zkRouter can verify cross-chain transactions without pledge assets. This mechanism makes it easier and more efficient to set up zkRouter nodes and enhances the degree of decentralization.

Applications

zkRouter can be applied to many application scenarios. Developers can use zkRouter to empower their applications and expand their application functions. At the same time, they can further increase their imagination in the development of blockchain ecological innovation, thereby bringing new application scenarios such as:

Asset cross-chain

The asset cross-chain bridge is currently one of the most suitable applications for zkRouter and is also what the crypto space needs. Furthermore, the asset cross-chain based on zkRouter does not rely on trust facilities, which can significantly reduce the possibility of cross-chain bridge security incidents and eliminate users' doubts about centralized bridges. At the same time, zkRouter has high versatility, is friendly to running or start-up cross-chain bridge projects, and supports a variety of cross-chain bridge models.

On-chain trusted oracle

zkRouter can credibly transfer and store the block header of the source chain to the target chain, and the information relayed through zkRouter can also be used by other dApps. This interaction allows other applications to determine whether a transaction happened on the source chain. Different from other off-chain information collection oracles, the oracles built on zkRouter will be more credible due to the characteristics of zero-knowledge proof results.

Multi-chain contract interoperability

zkRouter will provide a technical basis for multi-chain interoperability for smart contract development, and applications can efficiently and safely call multiple chains. Developers do not need to be limited to the solid thinking of single-chain development, nor do they need to make trade-offs between the advantages and disadvantages of multi-chains. Developers can efficiently complete cross-chain contract interoperability calls, like developing contracts on the same chain. This efficiency enables the original applications to enjoy the business expansion of multi-chain interoperability, such as multi-chain distribution of blockchain games and multi-chain lending in the Defi field.

Cross-chain Swap

Swapping on the chain is limited to a single-chain ecology. Although dapps can be deployed on multiple chains, the assets between chains could be more cohesive. Using zkRouter can effectively solve existing problems and empower cross-chain swaps.

Multi-chain issuance of tokens and NFT

Use zkRouter to easily mint and issue tokens and NFTs. Developers can also efficiently implement multi-chain deployment. This solves the accessibility and liquidity challenges traditional cross-chain bridges face, further improving user experience.

Conclusion

Multichain has proposed a trustless and general cross-chain infrastructure called zkRouter that utilizes zk-proof technology to address cross-chain infrastructure. This infrastructure has several advantages, including eliminating trust mechanisms, minimal on-chain computing requirements, universal applicability, low latency, and no need for asset mortgage.

Multichain strives to establish a secure and robust blockchain ecosystem and welcomes collaboration with other developers interested in contributing to the development and ecosystem of zkRouter.