Notice: This document is a work-in-progress for researchers and implementers.
- Introduction
- Custom types
- Constants
- Preset
- Configuration
- Containers
- Helper functions
- Beacon chain state transition function
- Testing
This upgrade adds blobs to the beacon chain as part of Deneb. This is an extension of the Capella upgrade.
The blob transactions are packed into the execution payload by the EL/builder with their corresponding blobs being independently transmitted and are limited by MAX_DATA_GAS_PER_BLOCK // DATA_GAS_PER_BLOB. However the CL limit is independently defined by MAX_BLOBS_PER_BLOCK.
| Name | SSZ equivalent | Description |
|---|---|---|
VersionedHash |
Bytes32 |
|
BlobIndex |
uint64 |
| Name | Value |
|---|---|
DOMAIN_BLOB_SIDECAR |
DomainType('0x0B000000') |
| Name | Value |
|---|---|
BLOB_TX_TYPE |
uint8(0x03) |
VERSIONED_HASH_VERSION_KZG |
Bytes1('0x01') |
| Name | Value | Description |
|---|---|---|
MAX_BLOB_COMMITMENTS_PER_BLOCK |
uint64(2**12) (= 4096) |
hardfork independent fixed theoretical limit same as LIMIT_BLOBS_PER_TX (see EIP 4844) |
MAX_BLOBS_PER_BLOCK |
uint64(2**2) (= 4) |
Maximum number of blobs in a single block limited by MAX_BLOB_COMMITMENTS_PER_BLOCK |
Note: BeaconBlock and SignedBeaconBlock types are updated indirectly.
class BeaconBlockBody(Container):
randao_reveal: BLSSignature
eth1_data: Eth1Data # Eth1 data vote
graffiti: Bytes32 # Arbitrary data
# Operations
proposer_slashings: List[ProposerSlashing, MAX_PROPOSER_SLASHINGS]
attester_slashings: List[AttesterSlashing, MAX_ATTESTER_SLASHINGS]
attestations: List[Attestation, MAX_ATTESTATIONS]
deposits: List[Deposit, MAX_DEPOSITS]
voluntary_exits: List[SignedVoluntaryExit, MAX_VOLUNTARY_EXITS]
sync_aggregate: SyncAggregate
# Execution
execution_payload: ExecutionPayload # [Modified in Deneb]
bls_to_execution_changes: List[SignedBLSToExecutionChange, MAX_BLS_TO_EXECUTION_CHANGES]
blob_kzg_commitments: List[KZGCommitment, MAX_BLOB_COMMITMENTS_PER_BLOCK] # [New in Deneb]class ExecutionPayload(Container):
# Execution block header fields
parent_hash: Hash32
fee_recipient: ExecutionAddress # 'beneficiary' in the yellow paper
state_root: Bytes32
receipts_root: Bytes32
logs_bloom: ByteVector[BYTES_PER_LOGS_BLOOM]
prev_randao: Bytes32 # 'difficulty' in the yellow paper
block_number: uint64 # 'number' in the yellow paper
gas_limit: uint64
gas_used: uint64
timestamp: uint64
extra_data: ByteList[MAX_EXTRA_DATA_BYTES]
base_fee_per_gas: uint256
# Extra payload fields
block_hash: Hash32 # Hash of execution block
transactions: List[Transaction, MAX_TRANSACTIONS_PER_PAYLOAD]
withdrawals: List[Withdrawal, MAX_WITHDRAWALS_PER_PAYLOAD]
excess_data_gas: uint256 # [New in Deneb]class ExecutionPayloadHeader(Container):
# Execution block header fields
parent_hash: Hash32
fee_recipient: ExecutionAddress
state_root: Bytes32
receipts_root: Bytes32
logs_bloom: ByteVector[BYTES_PER_LOGS_BLOOM]
prev_randao: Bytes32
block_number: uint64
gas_limit: uint64
gas_used: uint64
timestamp: uint64
extra_data: ByteList[MAX_EXTRA_DATA_BYTES]
base_fee_per_gas: uint256
# Extra payload fields
block_hash: Hash32 # Hash of execution block
transactions_root: Root
withdrawals_root: Root
excess_data_gas: uint256 # [New in Deneb]def kzg_commitment_to_versioned_hash(kzg_commitment: KZGCommitment) -> VersionedHash:
return VERSIONED_HASH_VERSION_KZG + hash(kzg_commitment)[1:]@dataclass
class NewPayloadRequest(object):
execution_payload: ExecutionPayload
versioned_hashes: Sequence[VersionedHash]def is_valid_versioned_hashes(self: ExecutionEngine, new_payload_request: NewPayloadRequest) -> bool:
"""
Return ``True`` if and only if the version hashes computed by the blob transactions of
``new_payload_request.execution_payload`` matches ``new_payload_request.version_hashes``.
"""
...def verify_and_notify_new_payload(self: ExecutionEngine,
new_payload_request: NewPayloadRequest) -> bool:
"""
Return ``True`` if and only if ``new_payload_request`` is valid with respect to ``self.execution_state``.
"""
if not self.is_valid_block_hash(new_payload_request.execution_payload):
return False
# [New in Deneb]
if not self.is_valid_versioned_hashes(new_payload_request):
return False
if not self.notify_new_payload(new_payload_request.execution_payload):
return False
return Truedef process_execution_payload(state: BeaconState, body: BeaconBlockBody, execution_engine: ExecutionEngine) -> None:
payload = body.execution_payload
# Verify consistency of the parent hash with respect to the previous execution payload header
assert payload.parent_hash == state.latest_execution_payload_header.block_hash
# Verify prev_randao
assert payload.prev_randao == get_randao_mix(state, get_current_epoch(state))
# Verify timestamp
assert payload.timestamp == compute_timestamp_at_slot(state, state.slot)
# [New in Deneb] Verify commitments are under limit
assert len(body.blob_kzg_commitments) <= MAX_BLOBS_PER_BLOCK
# Verify the execution payload is valid
# [Modified in Deneb] Pass `versioned_hashes` to Execution Engine
versioned_hashes = [kzg_commitment_to_versioned_hash(commitment) for commitment in body.blob_kzg_commitments]
assert execution_engine.verify_and_notify_new_payload(
NewPayloadRequest(execution_payload=payload, versioned_hashes=versioned_hashes)
)
# Cache execution payload header
state.latest_execution_payload_header = ExecutionPayloadHeader(
parent_hash=payload.parent_hash,
fee_recipient=payload.fee_recipient,
state_root=payload.state_root,
receipts_root=payload.receipts_root,
logs_bloom=payload.logs_bloom,
prev_randao=payload.prev_randao,
block_number=payload.block_number,
gas_limit=payload.gas_limit,
gas_used=payload.gas_used,
timestamp=payload.timestamp,
extra_data=payload.extra_data,
base_fee_per_gas=payload.base_fee_per_gas,
block_hash=payload.block_hash,
transactions_root=hash_tree_root(payload.transactions),
withdrawals_root=hash_tree_root(payload.withdrawals),
excess_data_gas=payload.excess_data_gas, # [New in Deneb]
)Note: The function initialize_beacon_state_from_eth1 is modified for pure Deneb testing only.
The BeaconState initialization is unchanged, except for the use of the updated deneb.BeaconBlockBody type
when initializing the first body-root.
def initialize_beacon_state_from_eth1(eth1_block_hash: Hash32,
eth1_timestamp: uint64,
deposits: Sequence[Deposit],
execution_payload_header: ExecutionPayloadHeader=ExecutionPayloadHeader()
) -> BeaconState:
fork = Fork(
previous_version=DENEB_FORK_VERSION, # [Modified in Deneb] for testing only
current_version=DENEB_FORK_VERSION, # [Modified in Deneb]
epoch=GENESIS_EPOCH,
)
state = BeaconState(
genesis_time=eth1_timestamp + GENESIS_DELAY,
fork=fork,
eth1_data=Eth1Data(block_hash=eth1_block_hash, deposit_count=uint64(len(deposits))),
latest_block_header=BeaconBlockHeader(body_root=hash_tree_root(BeaconBlockBody())),
randao_mixes=[eth1_block_hash] * EPOCHS_PER_HISTORICAL_VECTOR, # Seed RANDAO with Eth1 entropy
)
# Process deposits
leaves = list(map(lambda deposit: deposit.data, deposits))
for index, deposit in enumerate(deposits):
deposit_data_list = List[DepositData, 2**DEPOSIT_CONTRACT_TREE_DEPTH](*leaves[:index + 1])
state.eth1_data.deposit_root = hash_tree_root(deposit_data_list)
process_deposit(state, deposit)
# Process activations
for index, validator in enumerate(state.validators):
balance = state.balances[index]
validator.effective_balance = min(balance - balance % EFFECTIVE_BALANCE_INCREMENT, MAX_EFFECTIVE_BALANCE)
if validator.effective_balance == MAX_EFFECTIVE_BALANCE:
validator.activation_eligibility_epoch = GENESIS_EPOCH
validator.activation_epoch = GENESIS_EPOCH
# Set genesis validators root for domain separation and chain versioning
state.genesis_validators_root = hash_tree_root(state.validators)
# Fill in sync committees
# Note: A duplicate committee is assigned for the current and next committee at genesis
state.current_sync_committee = get_next_sync_committee(state)
state.next_sync_committee = get_next_sync_committee(state)
# Initialize the execution payload header
# If empty, will initialize a chain that has not yet gone through the Merge transition
state.latest_execution_payload_header = execution_payload_header
return state