Mev On Eth2

Discussion on MEV for Eth2, focusing on software stack inc. mev-boost, mev-relay, consensus client, etc.

Overview

Sequence Diagram

SignedValidatorRegistrationV1
	ValidatorRegistrationV1
		fee_recipient
		gas_limit
		timestamp
		pubkey
	signature

SignedBuilderBid
	BuilderBid
		header
		value
		pubkey
	signature

class SignedBlindedBeaconBlock(Container):
	BlindedBeaconBlock
		slot
		proposer_index
		parent_root
		state_root
		BlindedBeaconBlockBody
			...
			eth1_data: Eth1Data
			execution_payload_header
	signature

Signing

…

Commitment

TODO: What prevents the validator, after receiving the full block contents from modifying the transaction order that came from the builder?

1. “Validators receive the full block after they sent the signed blinded beacon block. Once that is done, they cannot propose any other block, otherwise they can and will get slashed.” - Discord
2. Wouldn’t it be advantageous for the design to have the relay (which is already a point of trust) to broadcast the block since it already got the blind signature for the block? With this setup, the validator never actually sees the block contents. - Thinking out loud…

Fee Recipient

Steps:

1. Block builder calls beacon client, asking for proposer for next slot which contains the fee recipient (source)
2. Block builder sends bid to the Relay (mev-relay service)
3. Relay forwards payload to the Block validation API service which simulates the block and ensures the fee recipient has been paid the amount stated in the payload.value field

Ongoing discussion about an “industry standard” way of doing payouts. For launch Flashbots is proceeding with proposer payment with a transaction from the builder at the end of the block. Relevant GH issue discussion

Wiki

Background Reading

• Original Architecture Proposal for MEV Boost by Flashbots
• “Unofficial” design proposal for MEV boost - good chunk made it into official implementation; provides backgound
• Beginners Guide to MEV Boost
• MEV-Boost Quickstart

Implementation Resources

• Builder Spec Schema and Builder Spec API - how Consensus Client (e.g. Prysm) communicates with MEV Boost
• Psuedo-code to construct BeaconBlockBody
• Relay Spec API - from Flashbots, bit confusing of a document
• Source Code
  • Sample block builder implementation built on Geth
  • Sample relay implementation
  • Tool to mock execution engine and consensus client for testing
  • Go schemas for all specs

Builder Spec Support