mirror of
https://github.com/status-im/eth2.0-specs.git
synced 2025-03-04 04:00:30 +00:00
5fafcd8274
As the chain keeps growing and duties are being added to the block construction and verification pipeline, it becomes increasingly difficult for clients to complete block duties on time leading to poor attestation performance and reorg frequency increases. This PR proposes to rebalance the relative timings of the 3 main activites, namely block production, attestation and aggregation such that they happen on 0/6/9 seconds into each slot instead of 0/4/8. This reduces the time for attestations to reach aggregators and aggregates to reach block producers but increases the time the consensus and execution clients have to produce and validate blocks. Each upgrade has so far increased complexity and processing requirements around block production and so will future upgraddes: due to increased size, blocks with blobs will take longer to dissemenate and additional verification / cryptography is needed to validate them.
185 lines
6.5 KiB
Markdown
185 lines
6.5 KiB
Markdown
# Deneb -- Honest Validator
|
|
|
|
**Notice**: This document is a work-in-progress for researchers and implementers.
|
|
|
|
## Table of contents
|
|
|
|
<!-- TOC -->
|
|
<!-- START doctoc generated TOC please keep comment here to allow auto update -->
|
|
<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
|
|
|
|
- [Introduction](#introduction)
|
|
- [Prerequisites](#prerequisites)
|
|
- [Helpers](#helpers)
|
|
- [`BlobsBundle`](#blobsbundle)
|
|
- [Modified `GetPayloadResponse`](#modified-getpayloadresponse)
|
|
- [Protocol](#protocol)
|
|
- [`ExecutionEngine`](#executionengine)
|
|
- [Modified `get_payload`](#modified-get_payload)
|
|
- [Beacon chain responsibilities](#beacon-chain-responsibilities)
|
|
- [Block and sidecar proposal](#block-and-sidecar-proposal)
|
|
- [Constructing the `BeaconBlockBody`](#constructing-the-beaconblockbody)
|
|
- [Blob KZG commitments](#blob-kzg-commitments)
|
|
- [Constructing the `SignedBlobSidecar`s](#constructing-the-signedblobsidecars)
|
|
- [Sidecar](#sidecar)
|
|
- [Validator duties](#validator-duties)
|
|
- [Attestations](#attestations)
|
|
- [Aggregates](#aggregates)
|
|
- [Sync committee messages](#sync-committee-messages)
|
|
- [Sync committee contributions](#sync-committee-contributions)
|
|
|
|
<!-- END doctoc generated TOC please keep comment here to allow auto update -->
|
|
<!-- /TOC -->
|
|
|
|
## Introduction
|
|
|
|
This document represents the changes to be made in the code of an "honest validator" to implement Deneb.
|
|
|
|
## Prerequisites
|
|
|
|
This document is an extension of the [Capella -- Honest Validator](../capella/validator.md) guide.
|
|
All behaviors and definitions defined in this document, and documents it extends, carry over unless explicitly noted or overridden.
|
|
|
|
All terminology, constants, functions, and protocol mechanics defined in the updated [Beacon Chain doc of Deneb](./beacon-chain.md) are requisite for this document and used throughout.
|
|
Please see related Beacon Chain doc before continuing and use them as a reference throughout.
|
|
|
|
## Helpers
|
|
|
|
### `BlobsBundle`
|
|
|
|
*[New in Deneb:EIP4844]*
|
|
|
|
```python
|
|
@dataclass
|
|
class BlobsBundle(object):
|
|
commitments: Sequence[KZGCommitment]
|
|
proofs: Sequence[KZGProof]
|
|
blobs: Sequence[Blob]
|
|
```
|
|
|
|
### Modified `GetPayloadResponse`
|
|
|
|
```python
|
|
@dataclass
|
|
class GetPayloadResponse(object):
|
|
execution_payload: ExecutionPayload
|
|
block_value: uint256
|
|
blobs_bundle: BlobsBundle # [New in Deneb:EIP4844]
|
|
```
|
|
|
|
## Protocol
|
|
|
|
### `ExecutionEngine`
|
|
|
|
#### Modified `get_payload`
|
|
|
|
Given the `payload_id`, `get_payload` returns the most recent version of the execution payload that
|
|
has been built since the corresponding call to `notify_forkchoice_updated` method.
|
|
|
|
```python
|
|
def get_payload(self: ExecutionEngine, payload_id: PayloadId) -> GetPayloadResponse:
|
|
"""
|
|
Return ExecutionPayload, uint256, BlobsBundle objects.
|
|
"""
|
|
# pylint: disable=unused-argument
|
|
...
|
|
```
|
|
|
|
## Beacon chain responsibilities
|
|
|
|
All validator responsibilities remain unchanged other than those noted below.
|
|
|
|
### Block and sidecar proposal
|
|
|
|
#### Constructing the `BeaconBlockBody`
|
|
|
|
##### Blob KZG commitments
|
|
|
|
*[New in Deneb:EIP4844]*
|
|
|
|
1. After retrieving the execution payload from the execution engine as specified in Capella,
|
|
use the `payload_id` to retrieve `blobs`, `blob_kzg_commitments`, and `blob_kzg_proofs`
|
|
via `get_payload(payload_id).blobs_bundle`.
|
|
2. Set `block.body.blob_kzg_commitments = blob_kzg_commitments`.
|
|
|
|
#### Constructing the `SignedBlobSidecar`s
|
|
|
|
*[New in Deneb:EIP4844]*
|
|
|
|
To construct a `SignedBlobSidecar`, a `signed_blob_sidecar` is defined with the necessary context for block and sidecar proposal.
|
|
|
|
##### Sidecar
|
|
|
|
Blobs associated with a block are packaged into sidecar objects for distribution to the network.
|
|
|
|
Each `sidecar` is obtained from:
|
|
```python
|
|
def get_blob_sidecars(block: BeaconBlock,
|
|
blobs: Sequence[Blob],
|
|
blob_kzg_proofs: Sequence[KZGProof]) -> Sequence[BlobSidecar]:
|
|
return [
|
|
BlobSidecar(
|
|
block_root=hash_tree_root(block),
|
|
index=index,
|
|
slot=block.slot,
|
|
block_parent_root=block.parent_root,
|
|
blob=blob,
|
|
kzg_commitment=block.body.blob_kzg_commitments[index],
|
|
kzg_proof=blob_kzg_proofs[index],
|
|
)
|
|
for index, blob in enumerate(blobs)
|
|
]
|
|
|
|
```
|
|
|
|
Then for each sidecar, `signed_sidecar = SignedBlobSidecar(message=sidecar, signature=signature)` is constructed and published to the associated sidecar topic, the `blob_sidecar_{subnet_id}` pubsub topic.
|
|
|
|
`signature` is obtained from:
|
|
|
|
```python
|
|
def get_blob_sidecar_signature(state: BeaconState,
|
|
sidecar: BlobSidecar,
|
|
privkey: int) -> BLSSignature:
|
|
domain = get_domain(state, DOMAIN_BLOB_SIDECAR, compute_epoch_at_slot(sidecar.slot))
|
|
signing_root = compute_signing_root(sidecar, domain)
|
|
return bls.Sign(privkey, signing_root)
|
|
```
|
|
|
|
The `subnet_id` for the `signed_sidecar` is calculated with:
|
|
- Let `blob_index = signed_sidecar.message.index`.
|
|
- Let `subnet_id = compute_subnet_for_blob_sidecar(blob_index)`.
|
|
|
|
```python
|
|
def compute_subnet_for_blob_sidecar(blob_index: BlobIndex) -> SubnetID:
|
|
return SubnetID(blob_index % BLOB_SIDECAR_SUBNET_COUNT)
|
|
```
|
|
|
|
After publishing the peers on the network may request the sidecar through sync-requests, or a local user may be interested.
|
|
|
|
The validator MUST hold on to sidecars for `MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS` epochs and serve when capable,
|
|
to ensure the data-availability of these blobs throughout the network.
|
|
|
|
After `MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS` nodes MAY prune the sidecars and/or stop serving them.
|
|
|
|
### Validator duties
|
|
|
|
The timing for sending attestation, aggregate, sync committee messages and contributions change.
|
|
|
|
#### Attestations
|
|
|
|
A validator must create and broadcast the `attestation` to the associated attestation subnet as soon as the validator has received a valid block from the expected block proposer for the assigned `slot`.
|
|
|
|
If the block has not been observed at `SECONDS_PER_SLOT / 2` seconds into the slot, the validator should send the attestation voting for its current head as selected by fork choice.
|
|
|
|
#### Aggregates
|
|
|
|
If the validator is selected to aggregate (`is_aggregator`), then they broadcast their best aggregate as a `SignedAggregateAndProof` to the global aggregate channel (`beacon_aggregate_and_proof`) `SECONDS_PER_SLOT * 3 / 4` seconds after the start of the slot.
|
|
|
|
#### Sync committee messages
|
|
|
|
This logic is triggered upon the same conditions as when producing an attestation.
|
|
|
|
#### Sync committee contributions
|
|
|
|
This logic is triggered upon the same conditions as when producing an aggregate.
|