eth2.0-specs/test_libs/pyspec/eth2spec/test/helpers/deposits.py

from eth2spec.test.helpers.keys import pubkeys, privkeys
from eth2spec.utils.bls import bls_sign
from eth2spec.utils.merkle_minimal import calc_merkle_tree_from_leaves, get_merkle_proof
from eth2spec.utils.ssz.ssz_impl import signing_root, hash_tree_root
from eth2spec.utils.ssz.ssz_typing import List


def build_deposit_data(spec, pubkey, privkey, amount, withdrawal_credentials, state=None, signed=False):
    deposit_data = spec.DepositData(
        pubkey=pubkey,
        withdrawal_credentials=withdrawal_credentials,
        amount=amount,
    )
    if signed:
        sign_deposit_data(spec, deposit_data, privkey, state)
    return deposit_data


def sign_deposit_data(spec, deposit_data, privkey, state=None):
    if state is None:
        # Genesis
        domain = spec.compute_domain(spec.DOMAIN_DEPOSIT)
    else:
        domain = spec.get_domain(
            state,
            spec.DOMAIN_DEPOSIT,
        )

    signature = bls_sign(
        message_hash=signing_root(deposit_data),
        privkey=privkey,
        domain=domain,
    )
    deposit_data.signature = signature


def build_deposit(spec,
                  state,
                  deposit_data_list,
                  pubkey,
                  privkey,
                  amount,
                  withdrawal_credentials,
                  signed):
    deposit_data = build_deposit_data(spec, pubkey, privkey, amount, withdrawal_credentials, state=state, signed=signed)
    index = len(deposit_data_list)
    deposit_data_list.append(deposit_data)
    root = hash_tree_root(List[spec.DepositData, 2**spec.DEPOSIT_CONTRACT_TREE_DEPTH](*deposit_data_list))
    tree = calc_merkle_tree_from_leaves(tuple([d.hash_tree_root() for d in deposit_data_list]))
    proof = list(get_merkle_proof(tree, item_index=index, tree_len=32)) + [(index + 1).to_bytes(32, 'little')]
    leaf = deposit_data.hash_tree_root()
    assert spec.is_valid_merkle_branch(leaf, proof, spec.DEPOSIT_CONTRACT_TREE_DEPTH + 1, index, root)
    deposit = spec.Deposit(proof=proof, data=deposit_data)

    return deposit, root, deposit_data_list


def prepare_genesis_deposits(spec, genesis_validator_count, amount, signed=False):
    deposit_data_list = []
    genesis_deposits = []
    for validator_index in range(genesis_validator_count):
        pubkey = pubkeys[validator_index]
        privkey = privkeys[validator_index]
        # insecurely use pubkey as withdrawal key if no credentials provided
        withdrawal_credentials = spec.BLS_WITHDRAWAL_PREFIX + spec.hash(pubkey)[1:]
        deposit, root, deposit_data_list = build_deposit(
            spec,
            None,
            deposit_data_list,
            pubkey,
            privkey,
            amount,
            withdrawal_credentials,
            signed,
        )
        genesis_deposits.append(deposit)

    return genesis_deposits, root


def prepare_state_and_deposit(spec, state, validator_index, amount, withdrawal_credentials=None, signed=False):
    """
    Prepare the state for the deposit, and create a deposit for the given validator, depositing the given amount.
    """
    deposit_data_list = []

    pubkey = pubkeys[validator_index]
    privkey = privkeys[validator_index]

    # insecurely use pubkey as withdrawal key if no credentials provided
    if withdrawal_credentials is None:
        withdrawal_credentials = spec.BLS_WITHDRAWAL_PREFIX + spec.hash(pubkey)[1:]

    deposit, root, deposit_data_list = build_deposit(
        spec,
        state,
        deposit_data_list,
        pubkey,
        privkey,
        amount,
        withdrawal_credentials,
        signed,
    )

    state.eth1_deposit_index = 0
    state.eth1_data.deposit_root = root
    state.eth1_data.deposit_count = len(deposit_data_list)
    return deposit