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EIP7594 -- The Beacon Chain

Notice: This document is a work-in-progress for researchers and implementers.

Table of contents

Introduction

Note: This specification is built upon Electra and is under active development.

Configuration

Execution

Name Value Description
MAX_BLOBS_PER_BLOCK_EIP7594 uint64(8) [New in EIP7594] Maximum number of blobs in a single block limited by MAX_BLOB_COMMITMENTS_PER_BLOCK

Execution payload

Modified process_execution_payload
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def 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)
    # Verify commitments are under limit
    assert len(body.blob_kzg_commitments) <= MAX_BLOBS_PER_BLOCK_EIP7594  # [Modified in EIP7594]
    # Verify the execution payload is valid
    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,
            parent_beacon_block_root=state.latest_block_header.parent_root,
            execution_requests=body.execution_requests,
        )
    )
    # 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),
        blob_gas_used=payload.blob_gas_used,
        excess_blob_gas=payload.excess_blob_gas,
    )

Testing

Note: The function initialize_beacon_state_from_eth1 is modified for pure EIP7594 testing only.

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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=EIP7594_FORK_VERSION,  # [Modified in EIP7594] for testing only
        current_version=EIP7594_FORK_VERSION,  # [Modified in EIP7594]
        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
        deposit_requests_start_index=UNSET_DEPOSIT_REQUESTS_START_INDEX,
    )

    # 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 deposit balance updates
    validator_pubkeys = [v.pubkey for v in state.validators]
    for deposit in state.pending_deposits:
        validator_index = ValidatorIndex(validator_pubkeys.index(deposit.pubkey))
        increase_balance(state, validator_index, deposit.amount)
    state.pending_deposits = []

    # Process activations
    for index, validator in enumerate(state.validators):
        balance = state.balances[index]
        validator.effective_balance = min(
            balance - balance % EFFECTIVE_BALANCE_INCREMENT, get_max_effective_balance(validator))
        if validator.effective_balance >= MIN_ACTIVATION_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
    state.latest_execution_payload_header = execution_payload_header

    return state