Threshold Encryption for Relay-Free Ethereum Block Building
Summary
The document proposes replacing Ethereum’s MEV-Boost relays with direct, private communication between block builders and proposers. Its design uses silent threshold encryption with validators’ existing BLS keys: a builder encrypts a proposed block for a fraction of the slot’s attester committee, and enough attestations allow the block to be decrypted. This aims to preserve builder privacy while reducing relay dependence and communication latency.
Threshold encryption alone does not establish block validity or honest bids, so the proposal pairs it with proofs, such as those from trusted execution environments, or potentially zero-knowledge proofs later. The article compares this approach with relay and data-availability alternatives, and discusses encryption costs, validator hint storage, adoption, and liveness risks if too few attesters are online. It presents a proposed architecture rather than deployed results; its viability depends on consensus-layer changes, broad validator participation, and acceptable storage and availability tradeoffs.
Key ideas
- Relays currently provide builder privacy and proposer safeguards, but concentrate block delivery among a small number of actors.
- Threshold encryption can keep block contents private until enough members of the attester committee attest.
- Validators can use existing BLS keys, avoiding new validator key material or an interactive key-generation ceremony.
- Separate proofs are still needed to establish block validity and bid honesty.
- Liveness, hint storage, adoption, and the risk of unavailable blocks remain important design constraints.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.