148 lines
5.2 KiB
Python
148 lines
5.2 KiB
Python
from typing import List
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from eth2spec.test.helpers.block import build_empty_block_for_next_slot, sign_block
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from eth2spec.test.helpers.keys import privkeys
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from eth2spec.utils.bls import bls_sign, bls_aggregate_signatures
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from eth2spec.utils.ssz.ssz_impl import hash_tree_root
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from eth2spec.utils.ssz.ssz_typing import Bitlist
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def build_attestation_data(spec, 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(spec, state).parent_root
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else:
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block_root = spec.get_block_root_at_slot(state, slot)
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current_epoch_start_slot = spec.get_epoch_start_slot(spec.get_current_epoch(state))
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if slot < current_epoch_start_slot:
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epoch_boundary_root = spec.get_block_root(state, spec.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 = spec.get_block_root(state, spec.get_current_epoch(state))
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if slot < current_epoch_start_slot:
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source_epoch = state.previous_justified_checkpoint.epoch
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source_root = state.previous_justified_checkpoint.root
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else:
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source_epoch = state.current_justified_checkpoint.epoch
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source_root = state.current_justified_checkpoint.root
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if spec.slot_to_epoch(slot) == spec.get_current_epoch(state):
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parent_crosslink = state.current_crosslinks[shard]
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else:
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parent_crosslink = state.previous_crosslinks[shard]
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return spec.AttestationData(
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beacon_block_root=block_root,
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source=spec.Checkpoint(epoch=source_epoch, root=source_root),
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target=spec.Checkpoint(epoch=spec.slot_to_epoch(slot), root=epoch_boundary_root),
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crosslink=spec.Crosslink(
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shard=shard,
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start_epoch=parent_crosslink.end_epoch,
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end_epoch=min(spec.slot_to_epoch(slot), parent_crosslink.end_epoch + spec.MAX_EPOCHS_PER_CROSSLINK),
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data_root=spec.ZERO_HASH,
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parent_root=hash_tree_root(parent_crosslink),
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),
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)
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def get_valid_attestation(spec, state, slot=None, signed=False):
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if slot is None:
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slot = state.slot
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epoch = spec.slot_to_epoch(slot)
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epoch_start_shard = spec.get_epoch_start_shard(state, epoch)
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committees_per_slot = spec.get_epoch_committee_count(state, epoch) // spec.SLOTS_PER_EPOCH
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shard = (epoch_start_shard + committees_per_slot * (slot % spec.SLOTS_PER_EPOCH)) % spec.SHARD_COUNT
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attestation_data = build_attestation_data(spec, state, slot, shard)
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crosslink_committee = spec.get_crosslink_committee(
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state,
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attestation_data.target.epoch,
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attestation_data.crosslink.shard,
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)
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committee_size = len(crosslink_committee)
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aggregation_bits = Bitlist[spec.MAX_VALIDATORS_PER_COMMITTEE](*([0] * committee_size))
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custody_bits = Bitlist[spec.MAX_VALIDATORS_PER_COMMITTEE](*([0] * committee_size))
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attestation = spec.Attestation(
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aggregation_bits=aggregation_bits,
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data=attestation_data,
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custody_bits=custody_bits,
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)
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fill_aggregate_attestation(spec, state, attestation)
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if signed:
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sign_attestation(spec, state, attestation)
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return attestation
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def sign_aggregate_attestation(spec, state, attestation_data, participants: List[int]):
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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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spec,
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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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return bls_aggregate_signatures(signatures)
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def sign_indexed_attestation(spec, state, indexed_attestation):
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participants = indexed_attestation.custody_bit_0_indices + indexed_attestation.custody_bit_1_indices
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indexed_attestation.signature = sign_aggregate_attestation(spec, state, indexed_attestation.data, participants)
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def sign_attestation(spec, state, attestation):
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participants = spec.get_attesting_indices(
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state,
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attestation.data,
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attestation.aggregation_bits,
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)
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attestation.signature = sign_aggregate_attestation(spec, state, attestation.data, participants)
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def get_attestation_signature(spec, state, attestation_data, privkey, custody_bit=0b0):
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message_hash = spec.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=spec.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(spec, state, attestation):
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crosslink_committee = spec.get_crosslink_committee(
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state,
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attestation.data.target.epoch,
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attestation.data.crosslink.shard,
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)
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for i in range(len(crosslink_committee)):
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attestation.aggregation_bits[i] = True
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def add_attestation_to_state(spec, state, attestation, slot):
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block = build_empty_block_for_next_slot(spec, state)
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block.slot = slot
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block.body.attestations.append(attestation)
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spec.process_slots(state, block.slot)
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sign_block(spec, state, block)
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spec.state_transition(state, block)
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