Deneb -- Honest Validator¶
- Introduction
- Prerequisites
- Helpers
BlobsBundle
- Modified
GetPayloadResponse
- Protocol
ExecutionEngine
- Beacon chain responsibilities
- Block and sidecar proposal
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 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 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]
Modified GetPayloadResponse
¶
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.
Beacon chain responsibilities¶
All validator responsibilities remain unchanged other than those noted below.
Block and sidecar proposal¶
Constructing the BeaconBlockBody
¶
ExecutionPayload¶
prepare_execution_payload
is updated from the Capella specs to provide the
parent beacon block root.
Note: In this section, state
is the state of the slot for the block proposal
without the block yet applied. That is, state
is the previous_state
processed through any empty slots up to the assigned slot using
process_slots(previous_state, slot)
.
Note: The only change made to prepare_execution_payload
is to add the parent
beacon block root as an additional parameter to the PayloadAttributes
.
Blob KZG commitments¶
[New in Deneb:EIP4844]
- The execution payload is obtained from the execution engine as defined above
using
payload_id
. The response also includes ablobs_bundle
entry containing the correspondingblobs
,commitments
, andproofs
. - Set
block.body.blob_kzg_commitments = commitments
.
Constructing the BlobSidecar
s¶
[New in Deneb:EIP4844]
To construct a BlobSidecar
, a 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 associated sidecar topic, the blob_sidecar_{subnet_id}
pubsub topic.
Each sidecar
is obtained from:
The subnet_id
for the blob_sidecar
is calculated with:
- Let
blob_index = blob_sidecar.index
. - Let
subnet_id = compute_subnet_for_blob_sidecar(blob_index)
.
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.