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EIP4844 with Prysm

Peep-an-EIP. March 29, 2023

Kasey and Terence

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EIP4844: Why and What?

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https://vitalik.ca/general/2021/04/07/sharding.html

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Today on Visa

https://usa.visa.com/dam/VCOM/global/about-visa/documents/aboutvisafactsheet.pdf

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Ethereum Today

  • 10 transactions per second
  • How to increase tps?
  • How to increase block space?
  • How to compete with global internet of value?

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The rollup centric roadmap

Rollups put skyscrapers on Ethereum

(H/T: Ben Edgington)

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Past: everything happens on L1

Ethereum L1 (~10 tps)

Defi, NFT, ICO, payment, DAO etc

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Today: with L2s

Ethereum L1 (~10 tps)

Defi, NFT… etc

L2s (~100 tps)

Defi

NFT

DAO

Defi

Payment

DAO

NFT

Defi

Optimised for security

Optimised for throughput and UX

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Today: L2 uses CALLDATA

Ethereum L1 (~10 tps) CALLDATA

L2s (~100 tps)

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EIP-4844: L2 uses BLOBDATA

Ethereum L1 (~10 tps) CALLDATA BLOBDATA

L2s (~1000 tps)

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Block

Blobs

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Block vs Blob

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Blockspace

Blobspace

Seen by all nodes

Yes

Yes

Size

1MB theoretical limit

128KB target / 256KB max

Storage

Execution client

Consensus client

EVM access

Yes

No

Longevity

Forever

18 days

Cost

Expensive (16 bytes / gas)

Cheap

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Blob transaction

Submitted to execution client mempool

Gossiped among execution clients (protocol: eth/68)

Blob transaction consists of

  • New transaction type: 0x05
  • Usual data fields (nonce, value, calldata, etc)
  • New field `blob_versioned_hashes` as part of commitment scheme
  • Encoded as SSZ

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Blob transaction end to end

L2 batch poster

Execution peer

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Mem pool

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Execution client

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Mem pool

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Consensus client

Validator

Consensus peer

Execution client

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L2 validators

Blob tx + regular tx

p2p: eth/68

Execution peer

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Mem pool

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Execution peer

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Mem pool

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Get blob bundle

Get and sign blobs

Gossip beacon block and blobs

Consensus peer

Consensus peer

Verify blob txs

Read blobs

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EIP4844 on Prysm

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What happens at every upgrade

P2P

State Transition

Beacon API Server

Validator (aka Prysm) API Server

Pool (like mempool)

Blocks and blobs

Engine API

https://github.com/ethereum/consensus-specs/blob/dev/specs/deneb/p2p-interface.md

https://github.com/ethereum/consensus-specs/blob/dev/specs/deneb/beacon-chain.md

https://github.com/ethereum/execution-apis/blob/main/src/engine/experimental/blob-extension.md

https://github.com/ethereum/beacon-APIs

https://github.com/ethereum/consensus-specs/blob/dev/specs/deneb/validator.md

Other consensus objects (i.e. exits, attestations)

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Beacon API changes

  • New endpoints
    • Blob signing endpoint
    • Blob downloading endpoint
  • New paradigm
    • Signing blinded block(?)
  • How to work with Prysm validator 2.0

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Validator changes

  • Sign blobs + blocks
  • No slashing equivocation involved. (Yay)
  • Optimization for latencies
  • What it means for DVT

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Crypto library

  • Switching to c-kzg
  • Audit starting April / 17
  • Finalizing polynomial commitment related interfaces
  • Improving security UX (ie. where to host trusted setup file)

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Block and blobs import

  • Can’t import block without blob
  • Queue them individually in sync pkg
  • When to request them?
  • How long to keep them for?
  • Potential DOS vectors?
  • This requires a good design, and plays a critical role in validator performance

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Block and blobs import

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Forward sync

  • Block sync remains the same
  • Blobs sync with additional complexity
  • Client gets “stuck” w/ non-empty block w/o blob
  • Peer scoring handler for blobs
  • Rate limiting handler for blobs

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Backfilling

  • We don't have backfilling
  • We need to implement back filling for block (~4 months)
  • We need to implement back filling for blob (~18 days)
  • Rate limiters
  • Peer selections

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Prysmctl

  • Download blobs
  • Verify blob tx
  • Send blob tx
  • More?

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Today’s progress

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Where we are today

  • Specs
    • Consensus: https://github.com/ethereum/consensus-specs/tree/dev/specs/deneb
    • Execution: https://eips.ethereum.org/EIPS/eip-4844
    • APIs: https://github.com/ethereum/execution-apis/blob/main/src/engine/experimental/blob-extension.md
  • Client implementation
    • four consensus implementations
    • four execution implementations
  • Devnets
    • Launched four devnets, devnet v5 in ~3-4 weeks
  • Tooling
    • Blobscan: https://blobscan.4844-devnet-4.ethpandaops.io/
  • KZG ceremony
    • On-going

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Devnet histories

  • Devnet v1: prysm-geth only
  • Devnet v2: data gas, sync testing
  • Devnet v3: rebased on top of shanghai, no withdrawal, begin using eth/68 to gossip blobs at execution layer
  • Devnet v4: blobs syncing hardened, all clients participated
  • Devnet v5: decoupled blobs, blob tx mempool hardening. (In a few weeks)

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