Discussion on the Security of Cross-Chain Protocols: Taking LayerZero as an Example

The security issues of cross-chain protocols have always been a hot topic in the Web3 field. In recent years, the losses caused by security incidents related to cross-chain protocols have been substantial, even exceeding the challenges faced by Ethereum's scaling solutions. The interoperability of cross-chain protocols is a key element of interconnection within the Web3 network, but the public's understanding of the security levels of these protocols is insufficient, making it difficult to accurately assess their risks.

Taking LayerZero as an example, its design architecture employs a Relayer to execute inter-chain communication, with an Oracle supervising the Relayer. This design eliminates the need for traditional consensus and multi-node validation of a third chain, providing users with a fast cross-chain experience. However, this lightweight design also has potential issues:

1. Simplifying multi-node verification to a single Oracle verification significantly reduces the security coefficient.
2. Assuming that Relayers and Oracles are always independent may be unrealistic and cannot fundamentally prevent collusion.

LayerZero, as a "super lightweight" cross-chain solution, is responsible only for message transmission and does not take responsibility for application security. Even if multiple parties are allowed to run relayers, it is difficult to fundamentally improve security, and it may instead lead to new issues.

If LayerZero cannot share security like Layer1 or Layer2, it is hard to call it a true infrastructure. It is more like middleware, allowing application developers to define their own security policies. This design may lead to ecological projects struggling to share a unified security standard.

Some research teams have pointed out potential security risks associated with LayerZero. For example, if an attacker gains configuration access, they could manipulate cross-chain assets by altering the oracle and relayer components. Additionally, vulnerabilities have been discovered in LayerZero's relayers that could potentially be exploited by insiders.

Looking back at the Bitcoin white paper, we can see that decentralization and the absence of a trusted third party are the core concepts of blockchain technology. However, the design of LayerZero seems to deviate from this concept. It requires users to trust Relayers, Oracles, and developers who build applications using LayerZero, while the participants in the multi-signature process are also pre-specified. More importantly, the entire cross-chain process lacks an on-chain verification mechanism for fraud proof or validity proof.

Therefore, although LayerZero has gained attention in the market, from the perspective of decentralization and trustlessness, it may not fully align with these core principles. Building a truly decentralized cross-chain protocol remains a direction worth exploring, and it may require considering the introduction of more advanced technologies, such as zero-knowledge proofs.

When evaluating cross-chain protocols, we need to return to the essence and focus on whether they truly achieve decentralization and trustlessness. Only by ensuring security can we build a truly reliable Web3 interoperability infrastructure.