FOCIL Breakout #12

[soispoke]

FOCIL Breakout #12, June 3, 2025, 14:00 UTC

Agenda

• Aikaterini presentation on Multiple Proposer Transaction Fee Mechanism Design: Robust Incentives Against Censorship and Bribery
• Implementation updates

🤖 config

• Duration in minutes : 60 mins
• Recurring meeting : true
• Call series : FOCIL Breakout
• Occurrence rate : bi-weekly
• Already a Zoom meeting ID : true
• Already on Ethereum Calendar : true
• Need YouTube stream links : false
• display zoom link in invite : true

[github-actions]

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Discourse Topic ID: 24409

• Action: Updated at 2025-06-04 10:55 UTC
• URL: https://ethereum-magicians.org/t/24409
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[poojaranjan]

Livestream:

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[jihoonsong]

The FOCIL session will be held in Berlin on June 11th at 3 PM. Check out the details here and please swing by if you're around!

FOCIL has been proposed as a candidate for Glamsterdam and there was a question regarding its urgency compared to other scaling EIPs. We’d like to encourage people to think about it and provide us with feedback.

Research

Multiple Proposer Transaction Fee Mechanism Design

• Aikaterini presented Multiple Proposer Transaction Fee Mechanism Design, a paper that proposes two payment mechanisms for FOCIL that enhance censorship resistance under bribery attacks.

• In generalized bribery attacks, an entity bribes includers and/or the block producer to censor a target transaction. A bribed block producer would fill their block with “fake” transactions to prevent it from being reorged to collect the bribe successfully. However, this approach forces the producer to pay the burn fees for all the fake transactions. To avoid incurring these fees, the block producer can insert a transaction that drains the balances of the fake transaction senders.

• How can we increase the cost of this deviation to discourage bribery attacks? If the block producer is not the block builder, they cannot insert a transaction that invalidates the fake transactions and hence be forced to pay the fees for these fake transactions. Thus, introducing an includer fee would further raise the cost of censorship, making bribery less attractive.

• We propose two kinds of transaction fee mechanism.

  • Double transaction fee mechanism: Users set two separate fees; one for the block producer and another for the includers. The includer fee goes to the includer who includes the transaction in their inclusion lists.
  • Single transaction fee mechanism: Users set only one fee and the protocol determines and allocates the includer fee to the eligible includer.

Development

The pending PR that revamps the EL section of the EIP has now been merged. Marc opened another PR proposing a solution that enables includers to use unique IDs to control the degree of overlap among IL transactions.

Implementation Updates

• Nethermind plans to begin testing interop soon.
• Lighthouse has started debugging interop but more work is still required.

Testing Updates

• EL testing has shared commits to the execution spec tests along with the draft PR for the execution specs. We aim to verify whether we can generate fixtures from these changes and EL clients can consume them correctly.

• CL testing has opened a draft PR to the consensus specs with a detailed rationale for the proposed changes. We will revisit this after the Berlin interop event.

FOCIL Metrics

• Katya has shared a draft PR adding FOCIL beacon metrics along with the newly created execution-metrics repo. Katya also mentioned that having standardized metrics facilitated client interop during PeerDAS development. Feedback or suggestions regarding these metrics are welcome!

Links

• FOCIL interop session in Berlin
• EIP-7805 Fork-Choice Inclusion Lists (FOCIL) as a candidate for Glamsterdam
• Multiple Proposer Transaction Fee Mechanism Design: Robust Incentives Against Censorship and Bribery — Paper
• Multiple Proposer Transaction Fee Mechanism Design: Robust Incentives Against Censorship and Bribery — Slides
• Revamping the EL Section of the EIP
• Introducing Unique IDs for Includers to Reduce Redundancy Among IL Transactions
• Execution Spec PR
• Execution Spec Tests Commits
• Consensus Spec Tests PR
• FOCIL Beacon Metrics PR
• execution-metrics