DLT Interoperability and More ⛓️#11 ⛓️ — SoK: Validating Bridges as a Scaling Solution for Blockchains

In this series, we analyze papers on blockchain and interoperability (and both).

This edition covers a recent paper on layer 2 technology.

Photo by Luke Besley on Unsplash

➡️ Title: SoK: Validating Bridges as a Scaling Solution for Blockchains
➡️ Authors: Patrick McCorry, Chris Buckland, Bennet Yee, Dawn Song

➡️ Paper source: https://arxiv.org/abs/2208.07119

➡️ Contributions:

This work is about validating bridge contract, an important component that enforces security properties on layer 2 solutions. These contracts assure the safety and liveness of the off-chain system especially if the operators turn out to be malicious.

— the authors systematize the components of a validating bridge, and present a list of relevant research problems for researchers to tackle relative to bridges

— the authors evaluate the state-of-art implementations to present their design choices, the financial cost of operation, and future direction. Please, also check our survey on blockchain interoperability!


💪 Strong points:

😞 Limitations:

🔥 Points of interest:

1. “The bridge contract can verify the data is publicly available such that anyone can recompute the database independently.” — known as the data availability problem. Typically, to solve this problem, L2s post the data directly on the bridging contract (we typically call them rollups). Platforms like Celestia are attempting to provide infrastructure to alleviate this problem.

2. “The bridge contract is convinced that all transactions executed in the commitment are valid and the commitment represents a valid new state of the database.”

3. “The bridge contract can enforce the eventual ordering and execution of transactions to ensure users can always unwind their positions and withdraw their funds.” — censorship resistance. Questions like “is MEV possible to exploit in L2 systems” depends on specific implementations — in principle, sequencers can benefit from MEV (sandwich attacks, for example). However, there are some proposals for fair-ordering protocols that would minimize nefarious effects of MEV. We talked a bit about MEV in our previous article.

🚀 How does it relate to our work at Técnico Lisboa, INESC-ID, and Blockdaemon? (views are my own and do not necessarily reflect the opinions of my employer)

🚀 What are the implications for our work?



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Rafael Belchior

R&D Engineer at Blockdaemon. Opinions and articles are my own and do not necessarily reflect the view of my employer. https://rafaelapb.github.io