428 lines
13 KiB
Python
428 lines
13 KiB
Python
from copy import deepcopy
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from py_ecc import bls
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from eth2spec.phase0.state_transition import (
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state_transition,
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)
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import eth2spec.phase0.spec as spec
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from eth2spec.utils.minimal_ssz import signing_root
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from eth2spec.phase0.spec import (
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# constants
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ZERO_HASH,
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MAX_EPOCHS_PER_CROSSLINK,
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# SSZ
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Attestation,
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AttestationData,
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AttestationDataAndCustodyBit,
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AttesterSlashing,
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BeaconBlock,
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BeaconBlockHeader,
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Crosslink,
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Deposit,
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DepositData,
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Eth1Data,
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ProposerSlashing,
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Transfer,
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VoluntaryExit,
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# functions
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convert_to_indexed,
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get_active_validator_indices,
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get_attesting_indices,
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get_block_root,
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get_block_root_at_slot,
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get_crosslink_committee,
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get_current_epoch,
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get_domain,
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get_epoch_start_slot,
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get_genesis_beacon_state,
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get_previous_epoch,
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get_shard_delta,
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hash_tree_root,
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slot_to_epoch,
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verify_merkle_branch,
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hash,
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)
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from eth2spec.utils.merkle_minimal import (
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calc_merkle_tree_from_leaves,
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get_merkle_proof,
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get_merkle_root,
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)
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privkeys = [i + 1 for i in range(1024)]
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pubkeys = [bls.privtopub(privkey) for privkey in privkeys]
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pubkey_to_privkey = {pubkey: privkey for privkey, pubkey in zip(privkeys, pubkeys)}
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def get_balance(state, index):
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return state.balances[index]
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def set_bitfield_bit(bitfield, i):
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"""
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Set the bit in ``bitfield`` at position ``i`` to ``1``.
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"""
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byte_index = i // 8
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bit_index = i % 8
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return (
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bitfield[:byte_index] +
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bytes([bitfield[byte_index] | (1 << bit_index)]) +
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bitfield[byte_index+1:]
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)
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def create_mock_genesis_validator_deposits(num_validators, deposit_data_leaves=None):
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if not deposit_data_leaves:
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deposit_data_leaves = []
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signature = b'\x33' * 96
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deposit_data_list = []
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for i in range(num_validators):
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pubkey = pubkeys[i]
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deposit_data = DepositData(
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pubkey=pubkey,
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# insecurely use pubkey as withdrawal key as well
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withdrawal_credentials=spec.BLS_WITHDRAWAL_PREFIX_BYTE + hash(pubkey)[1:],
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amount=spec.MAX_EFFECTIVE_BALANCE,
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signature=signature,
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)
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item = deposit_data.hash_tree_root()
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deposit_data_leaves.append(item)
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tree = calc_merkle_tree_from_leaves(tuple(deposit_data_leaves))
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root = get_merkle_root((tuple(deposit_data_leaves)))
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proof = list(get_merkle_proof(tree, item_index=i))
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assert verify_merkle_branch(item, proof, spec.DEPOSIT_CONTRACT_TREE_DEPTH, i, root)
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deposit_data_list.append(deposit_data)
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genesis_validator_deposits = []
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for i in range(num_validators):
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genesis_validator_deposits.append(Deposit(
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proof=list(get_merkle_proof(tree, item_index=i)),
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index=i,
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data=deposit_data_list[i]
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))
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return genesis_validator_deposits, root
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def create_genesis_state(num_validators, deposit_data_leaves=None):
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initial_deposits, deposit_root = create_mock_genesis_validator_deposits(
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num_validators,
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deposit_data_leaves,
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)
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return get_genesis_beacon_state(
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initial_deposits,
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genesis_time=0,
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genesis_eth1_data=Eth1Data(
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deposit_root=deposit_root,
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deposit_count=len(initial_deposits),
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block_hash=spec.ZERO_HASH,
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),
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)
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def build_empty_block_for_next_slot(state):
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empty_block = BeaconBlock()
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empty_block.slot = state.slot + 1
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empty_block.body.eth1_data.deposit_count = state.deposit_index
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previous_block_header = deepcopy(state.latest_block_header)
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if previous_block_header.state_root == spec.ZERO_HASH:
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previous_block_header.state_root = state.hash_tree_root()
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empty_block.parent_root = signing_root(previous_block_header)
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return empty_block
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def build_deposit_data(state, pubkey, privkey, amount):
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deposit_data = DepositData(
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pubkey=pubkey,
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# insecurely use pubkey as withdrawal key as well
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withdrawal_credentials=spec.BLS_WITHDRAWAL_PREFIX_BYTE + hash(pubkey)[1:],
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amount=amount,
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)
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signature = bls.sign(
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message_hash=signing_root(deposit_data),
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privkey=privkey,
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domain=get_domain(
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state,
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spec.DOMAIN_DEPOSIT,
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)
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)
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deposit_data.signature = signature
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return deposit_data
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def build_attestation_data(state, slot, shard):
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assert state.slot >= slot
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if slot == state.slot:
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block_root = build_empty_block_for_next_slot(state).parent_root
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else:
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block_root = get_block_root_at_slot(state, slot)
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current_epoch_start_slot = get_epoch_start_slot(get_current_epoch(state))
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if slot < current_epoch_start_slot:
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epoch_boundary_root = get_block_root(state, get_previous_epoch(state))
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elif slot == current_epoch_start_slot:
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epoch_boundary_root = block_root
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else:
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epoch_boundary_root = get_block_root(state, get_current_epoch(state))
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if slot < current_epoch_start_slot:
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justified_epoch = state.previous_justified_epoch
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justified_block_root = state.previous_justified_root
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else:
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justified_epoch = state.current_justified_epoch
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justified_block_root = state.current_justified_root
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crosslinks = state.current_crosslinks if slot_to_epoch(slot) == get_current_epoch(state) else state.previous_crosslinks
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return AttestationData(
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beacon_block_root=block_root,
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source_epoch=justified_epoch,
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source_root=justified_block_root,
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target_epoch=slot_to_epoch(slot),
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target_root=epoch_boundary_root,
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crosslink=Crosslink(
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shard=shard,
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epoch=min(slot_to_epoch(slot), crosslinks[shard].epoch + MAX_EPOCHS_PER_CROSSLINK),
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data_root=spec.ZERO_HASH,
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parent_root=hash_tree_root(crosslinks[shard]),
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),
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)
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def build_voluntary_exit(state, epoch, validator_index, privkey):
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voluntary_exit = VoluntaryExit(
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epoch=epoch,
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validator_index=validator_index,
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)
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voluntary_exit.signature = bls.sign(
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message_hash=signing_root(voluntary_exit),
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privkey=privkey,
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domain=get_domain(
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state=state,
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domain_type=spec.DOMAIN_VOLUNTARY_EXIT,
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message_epoch=epoch,
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)
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)
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return voluntary_exit
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def build_deposit(state,
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deposit_data_leaves,
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pubkey,
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privkey,
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amount):
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deposit_data = build_deposit_data(state, pubkey, privkey, amount)
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item = deposit_data.hash_tree_root()
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index = len(deposit_data_leaves)
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deposit_data_leaves.append(item)
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tree = calc_merkle_tree_from_leaves(tuple(deposit_data_leaves))
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root = get_merkle_root((tuple(deposit_data_leaves)))
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proof = list(get_merkle_proof(tree, item_index=index))
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assert verify_merkle_branch(item, proof, spec.DEPOSIT_CONTRACT_TREE_DEPTH, index, root)
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deposit = Deposit(
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proof=list(proof),
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index=index,
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data=deposit_data,
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)
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return deposit, root, deposit_data_leaves
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def get_valid_proposer_slashing(state):
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current_epoch = get_current_epoch(state)
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validator_index = get_active_validator_indices(state, current_epoch)[-1]
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privkey = pubkey_to_privkey[state.validator_registry[validator_index].pubkey]
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slot = state.slot
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header_1 = BeaconBlockHeader(
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slot=slot,
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parent_root=ZERO_HASH,
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state_root=ZERO_HASH,
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body_root=ZERO_HASH,
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)
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header_2 = deepcopy(header_1)
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header_2.parent_root = b'\x02' * 32
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header_2.slot = slot + 1
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domain = get_domain(
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state=state,
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domain_type=spec.DOMAIN_BEACON_PROPOSER,
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)
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header_1.signature = bls.sign(
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message_hash=signing_root(header_1),
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privkey=privkey,
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domain=domain,
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)
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header_2.signature = bls.sign(
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message_hash=signing_root(header_2),
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privkey=privkey,
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domain=domain,
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)
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return ProposerSlashing(
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proposer_index=validator_index,
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header_1=header_1,
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header_2=header_2,
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)
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def get_valid_attester_slashing(state):
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attestation_1 = get_valid_attestation(state)
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attestation_2 = deepcopy(attestation_1)
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attestation_2.data.target_root = b'\x01' * 32
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return AttesterSlashing(
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attestation_1=convert_to_indexed(state, attestation_1),
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attestation_2=convert_to_indexed(state, attestation_2),
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)
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def get_valid_attestation(state, slot=None):
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if slot is None:
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slot = state.slot
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if slot_to_epoch(slot) == get_current_epoch(state):
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shard = (state.latest_start_shard + slot) % spec.SLOTS_PER_EPOCH
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else:
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previous_shard_delta = get_shard_delta(state, get_previous_epoch(state))
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shard = (state.latest_start_shard - previous_shard_delta + slot) % spec.SHARD_COUNT
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attestation_data = build_attestation_data(state, slot, shard)
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crosslink_committee = get_crosslink_committee(state, attestation_data.target_epoch, attestation_data.crosslink.shard)
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committee_size = len(crosslink_committee)
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bitfield_length = (committee_size + 7) // 8
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aggregation_bitfield = b'\xC0' + b'\x00' * (bitfield_length - 1)
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custody_bitfield = b'\x00' * bitfield_length
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attestation = Attestation(
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aggregation_bitfield=aggregation_bitfield,
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data=attestation_data,
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custody_bitfield=custody_bitfield,
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)
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participants = get_attesting_indices(
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state,
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attestation.data,
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attestation.aggregation_bitfield,
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)
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assert len(participants) == 2
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signatures = []
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for validator_index in participants:
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privkey = privkeys[validator_index]
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signatures.append(
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get_attestation_signature(
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state,
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attestation.data,
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privkey
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)
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)
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attestation.aggregation_signature = bls.aggregate_signatures(signatures)
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return attestation
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def get_valid_transfer(state, slot=None, sender_index=None, amount=None, fee=None):
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if slot is None:
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slot = state.slot
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current_epoch = get_current_epoch(state)
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if sender_index is None:
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sender_index = get_active_validator_indices(state, current_epoch)[-1]
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recipient_index = get_active_validator_indices(state, current_epoch)[0]
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transfer_pubkey = pubkeys[-1]
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transfer_privkey = privkeys[-1]
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if fee is None:
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fee = get_balance(state, sender_index) // 32
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if amount is None:
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amount = get_balance(state, sender_index) - fee
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transfer = Transfer(
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sender=sender_index,
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recipient=recipient_index,
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amount=amount,
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fee=fee,
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slot=slot,
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pubkey=transfer_pubkey,
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signature=ZERO_HASH,
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)
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transfer.signature = bls.sign(
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message_hash=signing_root(transfer),
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privkey=transfer_privkey,
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domain=get_domain(
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state=state,
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domain_type=spec.DOMAIN_TRANSFER,
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message_epoch=get_current_epoch(state),
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)
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)
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# ensure withdrawal_credentials reproducable
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state.validator_registry[transfer.sender].withdrawal_credentials = (
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spec.BLS_WITHDRAWAL_PREFIX_BYTE + spec.hash(transfer.pubkey)[1:]
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)
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return transfer
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def get_attestation_signature(state, attestation_data, privkey, custody_bit=0b0):
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message_hash = AttestationDataAndCustodyBit(
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data=attestation_data,
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custody_bit=custody_bit,
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).hash_tree_root()
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return bls.sign(
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message_hash=message_hash,
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privkey=privkey,
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domain=get_domain(
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state=state,
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domain_type=spec.DOMAIN_ATTESTATION,
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message_epoch=attestation_data.target_epoch,
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)
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)
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def fill_aggregate_attestation(state, attestation):
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crosslink_committee = get_crosslink_committee(state, attestation.data.target_epoch, attestation.data.crosslink.shard)
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for i in range(len(crosslink_committee)):
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attestation.aggregation_bitfield = set_bitfield_bit(attestation.aggregation_bitfield, i)
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def add_attestation_to_state(state, attestation, slot):
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block = build_empty_block_for_next_slot(state)
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block.slot = slot
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block.body.attestations.append(attestation)
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state_transition(state, block)
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def next_slot(state):
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"""
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Transition to the next slot via an empty block.
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Return the empty block that triggered the transition.
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"""
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block = build_empty_block_for_next_slot(state)
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state_transition(state, block)
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return block
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def next_epoch(state):
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"""
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Transition to the start slot of the next epoch via an empty block.
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Return the empty block that triggered the transition.
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"""
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block = build_empty_block_for_next_slot(state)
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block.slot += spec.SLOTS_PER_EPOCH - (state.slot % spec.SLOTS_PER_EPOCH)
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state_transition(state, block)
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return block
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def get_state_root(state, slot) -> bytes:
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"""
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Return the state root at a recent ``slot``.
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"""
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assert slot < state.slot <= slot + spec.SLOTS_PER_HISTORICAL_ROOT
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return state.latest_state_roots[slot % spec.SLOTS_PER_HISTORICAL_ROOT]
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