Cross-Chain Bridge Assessment Process

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Proposed Implementation of a Multi-Bridge, Agnostic Solution

Over the past few months, LI.FI (a bridge aggregator supporting 13 bridges) has been closely monitoring the development in Uniswap’s Forum related to the BNB Chain Deployment Proposal, its subsequent Snapshot Poll which ended on Jan 31, and the current on-chain vote in favor of implementing Wormhole.

While we applaud the interest shown by key stakeholders of the crypto ecosystem in finding a suitable bridging solution for Uniswap’s Cross-Chain Governance, we strongly recommend that Uniswap not select one bridge provider for its BNB Chain Deployment Proposal. Specifically, we do not believe the BNB Chain Deployment Proposal should move forward before more research can be done, even if this may come as a letdown to many community members – be it bridge builders or other individuals.

Instead, we urge the Uniswap Foundation and the Uniswap community to fully immerse themselves in the Cross-Chain Assessment Process outlined by @devinwalsh. While the sprint to move to BNB Chain before the business license expires is important, we believe finding a long-term solution for cross-chain governance to be far more important than the short-term win of deploying V3 code first. There will be new chains, new versions of Uniswap, but there will never be another chance to expand governance safely and securely on the first try. Uniswap is a market leader in design (AMMs), token structure (airdrops), and overall competency, and LI.FI believes that the model Uniswap chooses for cross-chain governance has a high chance of becoming industry standard. We – as members of the crypto industry – want to see this done the correct way, and from the start.

Bridges, specifically arbitrary messaging bridges (AMBs), are in the nascent stages of development. Short-term, Wormhole, LayerZero, Celer, Axelar and deBridge are certainly viable solutions for cross-chain governance and have received substantial traction in terms of volume at the liquidity layer and development by dApps at the messaging layer.

That being said, we at LI.FI have done the research on AMBs (Navigating Arbitrary Messaging Bridges) and have delved deeply into the pros and cons of eight different AMB solutions. Our conclusion is simple: no single AMB is tested enough to be considered a robust and secure solution that a project of Uniswap’s size can solely rely on at this point. If there was a single, obvious AMB solution that could be trusted by Uniswap, then this forum post would not be necessary. Lest it be forgotten, two major AMBs were exploited in the past twelve months (Nomad and Wormhole), while LayerZero has also come under fire recently for its security model (Prestwich, L2Beat). We do not say this as condemnation, rather, we point this out to highlight just how difficult it is to build secure AMBs and the subsequent risks a dApp is exposed to by choosing a single bridging solution. In addition to this sentiment, we believe AMBs like Axelar, Synapse, Hyperlane, Multichain, Connext Amarok, and Hop deserve to be considered by Uniswap and the deadline of two and half weeks is too short for them to be formally introduced, debated, and voted upon again.

To summarize, LI.FI stands staunchly behind the concerns previously raised by @Kydo, @AlexSmirnov, and @modong. LI.FI believes that a multi-bridge, agnostic approach is best suited for Uniswap cross-chain governance because of the following reasons:

  • By picking one bridging solution, Uniswap will be selecting a winner in a niche that is perhaps yet to find the most optimal solution, resulting in a lack of innovation going forward and a dominance by the AMB that will not help the space move forward in the right direction.
  • With bridges, trust is a spectrum, and all the AMBs make different trade-offs resulting in unique strengths and weaknesses. However, when it comes to Uniswap’s use case of cross-chain governance, security can never be a trade-off. This is where a multi-bridge solution comes in to overcome these trust trade-offs, offering better security than any one bridging solution.
  • Aggregating the best, most trusted AMBs will be in the best interest of the Uniswap community as, irrespective of shortcomings in any individual bridge, Uniswap will always receive the best services required for cross-chain governance.

So, where do we go from here?

More research is in order, which we believe should be two-pronged.

1. Cross-Chain Bridge Assessment Framework

We would like to add our own feedback to Devin’s framework and add an additional step to the process.

The MMA solution or any other multi-bridge solution is built on the idea of Uniswap choosing multiple bridges as “adapters.” The first thing to do, therefore, is to determine which bridges meet Uniswap standards, as outlined by @devinwalsh.

We believe that Uniswap should first build a unique framework to both quantitatively and qualitatively measure and allow for the ranking of different bridge solutions by the engineering team. This would decrease the workload of the engineering team by letting them focus on stress-testing bridge solutions without having to create the parameters of such a test themselves.

As one of the largest players in DeFi, Uniswap has the chance to create the de facto bridge assessment criterion.

By our estimation, there are four bridge framework solutions currently in the ether.

Uniswap has the chance to build upon, combine, and quantify the works of four major research pieces without having to start from scratch.

With that in mind, we recommend that Devin’s initial Cross Chain Bridge Assessment make room for four researchers, who can help build this framework to assist the engineering team, who can then test out different bridging solutions based on the criteria mentioned in the framework and select which bridges make the cut to become a part of the multi-bridge solution.

The researchers will then explain the decision of the team through easy to digest articles, which can be used by other builders to assess bridges for their own dApps and by users to expand their knowledge of bridges and make more informed decisions when it comes to choosing a bridging solution for their needs. To this end, collaborations with other public good infrastructure projects like L2BEAT, Ethereum.org, among others, should also be considered to spread awareness and educate the public about bridges.

As Devin laid out, these individuals should be available for 10-15 hours per week over the next few weeks to participate in the assessment process, and to write up their findings in a report to share with the community.

To this end, we recommend Peter Robinson, Arjun Chand, Ermyas Abebe, and Bartek Kiepuszewski (though we believe Uniswap should have the final call here).

We believe the current timeframe is aggressive but doable. However, if the list of bridges were to expand, we would recommend pushing back the March 27th date.

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2. Consideration of Making the Universal Governance Model an EIP

Uniswap pushing for a cross-chain governance EIP would be net positive for the industry, in our opinion, specifically in the context of a multi-bridge solution. Such an EIP would give dApps a shared template for creating safe, secure governance modules, while also giving flexibility for dApps to choose different bridging solutions based on their security, time, and cost preferences.

To that end, we believe that Uniswap should create and propose a new cross-chain EIP based on the design outlined by Mo Dong from Celer and Alex from deBridge (with, of course, any tweaks recommended by the engineering and research team).

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Additionally, there are two EIPs and one forum post that Uniswap should consider learning from and building upon in addition to the framework above.

  • EIP 5164, as explained by Brendan Asseltine, is a PoolTogether and Hop-backed EIP looking to standardize governance message passing. While EIP 5164 is not a perfect fit for Uniswap – it proposes that all bridges provide the same interface to apps so that apps can just build against this interface and choose one bridge later – it does provide insight into the difficulties that EIP writers will have in coming up with a single design.
  • EIP 6170, is a common smart contract interface for interacting with messaging protocols.
  • Principled approach to bridges, proposes block header based bridges.

In our estimation, none of these solutions have captured enough mindshare to become industry standard. However, they have all pushed the envelope in what can be done in standardizing messaging, and Uniswap could learn much from it.

We recommend that Uniswap employ the same four-engineering team to standardize the MMA solution as an EVM-compatible EIP.

Given Uniswap’s position and influence in the ecosystem, it has the power to push an EIP that can potentially become the de-facto solution for any project indulging in cross-chain governance.

Conclusion

A multi-bridge, agnostic solution that the community invests resources into is a win-win-win for all the parties involved (Uniswap, bridging solutions, and the dApps that will implement this solution for cross-chain governance in the future).

As Devin said, the developments as a result of the proposed deployment on BNB Chain are net-positive for the ecosystem. Open discussions about bridge designs and frameworks for assessing security risks associated with them are exactly what we need to fast-forward the maturity of the bridging solutions and enable development of secure bridges.

We look forward to the feedback of the UF and the community on our proposal.

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