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FAQ

How does Bolt relate to PEPC?​

PEPC (Protocol-enforced proposer commitments) is an in-protocol solution to the proposer agency issue on Ethereum. In short, PEPC would add the ability for a proposer to commit to certain validity conditions of the block they are proposing, and if they aren't met, the block is considered invalid by the attesters and cannot be included in the chain.

Bolt approaches the problem from a different angle: it doesn't require any changes to the Ethereum consensus protocol, and instead relies on infrastructure to enforce these guarantees with economic credibility (i.e. slashing the proposer if they don't meet the conditions they committed to). This has a couple of advantages:

  1. No need for a hard fork: Bolt can be deployed on Ethereum today, without any changes to the protocol.
  2. More flexible commitments: Bolt can enforce any kind of condition that can be proven on-chain. We are starting with inclusion and ordering guarantees which rely on Merkle proofs, but the system can be seamlessly extended to more complex conditions with the use of ZK proofs and other cryptographic techniques.
  3. More granular: One of PEPC's limitations is the ability to play "fast games", where conditions can only act on a timeframe that is compatible with the 12 second slot time of the Beacon chain. Bolt has no such limitation, and can enforce conditions on a much shorter timeframe (provided that it can be proven on-chain).

One key difference between the original PEPC proposal and Bolt is the failure mode: PEPC operates under pessimistic settings (the protocol will not let a proposer renege on their commitment, invalidating the block if it does not satisfy the commitments) while Bolt operates under optimistic settings (the proposer can renage on their commitments, but will be financially penalized for it).

How does Bolt relate to X?​

Where X:

  • PEPC-Boost: PEPC-Boost is the general description for a family of ideas that try to achieve the same goals as PEPC out of the Ethereum consensus layer. Under this framework, Bolt can be seen as a specific implementation of a PEPC-Boost solution. The original PEPC-Boost design is a bit more opinionated, and proposes a design with "TOB" and "ROB" auctions arbitrated by a Relay for partial block building. There is also a more concrete implementation of this idea. Compared to this design, Bolt doesn't introduce a trusted Relay, and doesn't require a second block-building phase unlike PEPC-Boost (which adds significant latency to the PBS auction).
  • Mev-Boost++: This research experiment makes use of Eigenlayer, EigenDA and Shutter threshold encryption to achieve permissionless commitments and partial block building compatible with ePBS. It's really interesting in our opinion, and it exposes how a fast DA network could be one of the most promising ways to achieve more complex types of collaborative commitments in the future through Bolt.
  • MEV-Auction (XGA): This idea is spiritually similar to PEPC-Boost, where the block is built in two parts, for which a just-in-time auction is held to determine the first part (which is more valuable for MEV extraction). However, XGA seems mostly focused on MEV use cases, and it introduces a trusted relay and trusted proposer opt-in, without the economic credibility guarantees that Bolt provides.
  • SUAVE: For the context of PBS, SUAVE can be best described as a decentralized builder that could integrate with Bolt (just like any other block builder). There is strong potential synergy between SUAVE and Bolt, and we are looking into ways to integrate the two in the future. One promising direction is the delegated pricing mechanism that SUAVE can introduce thanks to its privacy and verifiability guarantees, coupled with its grade of sophistication compared to the one of Ethereum validators. Another synergy includes the ability to use SUAVE to buy commitments for block building itself, giving it the ability to provide preconfirmations directly to users.

How is Bolt permissionless?​

Bolt's design focuses heavily on proposer agency. This choice was made to ensure that market dynamics will be driven by the supply side of the commitments market. Practically, this means that Bolt is a framework under which proposers regain control over their blockspace and can monetize it in a way that is not possible with the current PBS pipeline.

Block builders and Relays will be active participants in this system, but their responsibilities are limited to the satisfaction of the commitments made by proposers. They do not have any control over the commitments themselves.

To recap, Bolt is permissionless because:

  1. It doesn't introduce any new trusted entities.
  2. It doesn't overload the responsibilities of existing PBS entities (builders and relays).
  3. It's based on economic credibility as the only enforcement mechanism driving the induced commitments market.
  4. It relies on fallback block building as a last resort to ensure that relays and builders aren't critical to the proposers' operation.

Please refer to the Architecture page for more details on how Bolt works.