Foundations of Transaction Fee Mechanism Design with Elaine Shi | a16z crypto research talks

TL;DR

Designing a transaction fee mechanism that satisfies user incentive, miner incentive, and side contract proofness properties in a decentralized environment is challenging.

Transcript

I'm very happy to be here visiting this amazing group I'm going to talk about transaction fee mechanism Design This is John work with my student Hau Chan so transaction fee mechanism right this is what we need um on the blockchain because the space on the blockchain is scarce but there are many users who there who want their transactions to be conf... Read More

Key Insights

• 🤱 Transaction fee mechanisms on the blockchain need to balance user incentive, miner incentive, and side contract proofness properties.
• 🏛️ Classical mechanisms like first-price auctions and second-price auctions have limitations in a decentralized setting due to untruthful reporting and the miner being a strategic player.
• 😚 Ethereum's EIP1559 comes close to the dream mechanism but does not fully satisfy all properties.
• 🤱 Designing a transaction fee mechanism is challenging, especially in a decentralized environment, where the miner's behavior must also be incentivized.
• 🚫 The impossibility of achieving the dream mechanism with a finite block size highlights the limitations of existing mechanisms.
• 🧑‍🏭 Considering the cost of unconfirmed transactions and the resilience of the mechanism through the discount factor is crucial.
• 🤱 Randomization in transaction fee mechanisms is often necessary to achieve desired outcomes.

Questions & Answers

Q: What is the current transaction fee mechanism used in Bitcoin and why is it not ideal?

Bitcoin currently uses a first-price auction mechanism where the highest bidders have their transactions confirmed. However, this mechanism encourages untruthful reporting and incentivizes users to barely bid enough to be among the top bidders to pay less.

Q: Why is it challenging to design a transaction fee mechanism in a decentralized environment?

In a decentralized environment, the miner can also be a strategic player, making it necessary to incentivize both users and miners to behave honestly. Classical mechanisms in mechanism design do not consider the miner as a strategic player.

Q: How does Ethereum's EIP1559 transaction fee mechanism come close to the dream mechanism?

Ethereum's EIP1559 uses a hybrid auction mechanism where, in congested times, it behaves like a first-price auction, and in uncongested times, it acts like a posted price auction. All payments made are burnt, and the miner's revenue rule is not a significant factor in the mechanism.

Q: Is it possible to have a dream transaction fee mechanism with a finite block size?

No, according to the analysis, it is impossible to achieve a transaction fee mechanism that satisfies user incentive, miner incentive, and side contract proofness properties when the block size is finite.

Summary & Key Takeaways

• Transaction fee mechanisms are essential on the blockchain to confirm transactions, but current mechanisms like first-price auctions and second-price auctions have limitations in a decentralized setting.

• The dream transaction fee mechanism should ensure truthful bidding by users and honest behavior by miners, while also considering side contract proofness in a decentralized environment.

• Ethereum's EIP1559 comes close to the dream mechanism, but no mechanism fully satisfies all three properties. Finite block size makes achieving the dream mechanism impossible.