def mock_make_child(parent_state, parent, skips, attester_share=0.8, crosslink_shards=[]):
crystallized_state, active_state = parent_state
parent_attestation = serialize(parent)
indices, main_signer = get_attesters_and_signer(crystallized_state, active_state, skips)
print('Selected indices: %r' % indices)
print('Selected main signer: %d' % main_signer)
# Randomly pick indices to include
bitfield = [1 if random.random() < attester_share else 0 for i in indices]
# Attestations
sigs = [bls.sign(parent_attestation, keymap[crystallized_state.active_validators[indices[i]].pubkey])
for i in range(len(indices)) if bitfield[i]]
attestation_aggregate_sig = bls.aggregate_sigs(sigs)
print('Aggregated sig')
attestation_bitmask = bytearray((len(bitfield)-1) // 8 + 1)
for i, b in enumerate(bitfield):
attestation_bitmask[i//8] ^= (128 >> (i % 8)) * b
print('Aggregate bitmask:', bin(int.from_bytes(attestation_bitmask, 'big')))
# Randomly pick indices to include for crosslinks
shard_aggregate_votes = []
for shard, crosslinker_share in crosslink_shards:
print('Making crosslink in shard %d' % shard)
indices = get_shard_attesters(crystallized_state, shard)
print('Indices: %r' % indices)
bitfield = [1 if random.random() < crosslinker_share else 0 for i in indices]
bitmask = bytearray((len(bitfield)+7) // 8)
for i, b in enumerate(bitfield):
bitmask[i//8] ^= (128 >> (i % 8)) * b
print('Bitmask:', bin(int.from_bytes(bitmask, 'big')))
shard_block_hash = blake(bytes([shard]))
crosslink_attestation_hash = get_crosslink_aggvote_msg(shard, shard_block_hash, crystallized_state)
sigs = [bls.sign(crosslink_attestation_hash, keymap[crystallized_state.active_validators[indices[i]].pubkey])
for i in range(len(indices)) if bitfield[i]]
v = AggregateVote(shard_id=shard,
shard_block_hash=shard_block_hash,
signer_bitmask=bitmask,
aggregate_sig=list(bls.aggregate_sigs(sigs)))
shard_aggregate_votes.append(v)
print('Added %d shard aggregate votes' % len(crosslink_shards))
# State calculations
o = Block(parent_hash=blake(parent_attestation),
skip_count=skips,
randao_reveal=blake(str(random.random()).encode('utf-8')),
attestation_bitmask=attestation_bitmask,
attestation_aggregate_sig=list(attestation_aggregate_sig),
shard_aggregate_votes=shard_aggregate_votes,
main_chain_ref=b'\x00'*32,
state_hash=b'\x00'*64)
print('Generated preliminary block header')
new_crystallized_state, new_active_state = \
compute_state_transition((crystallized_state, active_state), parent, o, verify_sig=False)
print('Calculated state transition')
if crystallized_state == new_crystallized_state:
o.state_hash = blake(parent.state_hash[:32] + blake(serialize(new_active_state)))
else:
o.state_hash = blake(blake(serialize(new_crystallized_state)) + blake(serialize(new_active_state)))
# Main signature
o.sign(keymap[crystallized_state.active_validators[main_signer].pubkey])
print('Signed')
return o, new_crystallized_state, new_active_state
def mock_make_attestations(parent_state, block, attester_share=0.8):
crystallized_state, active_state = parent_state
cycle_length = config['cycle_length']
in_cycle_slot_height = block.slot_number % cycle_length
indices = crystallized_state.indices_for_slots[cycle_length +
in_cycle_slot_height]
print("Generating attestations for shards: %s" % len(indices))
attestations = []
for shard_and_committee in indices:
shard_id = shard_and_committee.shard_id
committee_indices = shard_and_committee.committee
print("Generating attestation for shard %s" % shard_id)
print("Committee size %s" % len(committee_indices))
# Create attestation
attestation = AttestationRecord(
slot=block.slot_number,
shard_id=shard_and_committee.shard_id,
oblique_parent_hashes=[],
shard_block_hash=blake(bytes(str(shard_id), 'utf-8')),
attester_bitfield=get_empty_bitfield(len(committee_indices)))
# Randomly pick indices to include
is_attesting = [
random.random() < attester_share
for _ in range(len(committee_indices))
]
# Proposer always attests
is_attesting[0] = True
# Generating signatures and aggregating result
parent_hashes = get_hashes_to_sign(active_state, block, config)
message = blake(
attestation.slot.to_bytes(8, byteorder='big') +
b''.join(parent_hashes) +
shard_id.to_bytes(2, byteorder='big') +
attestation.shard_block_hash)
sigs = [
bls.sign(message,
keymap[crystallized_state.validators[indice].pubkey])
for i, indice in enumerate(committee_indices)
if is_attesting[i]
]
attestation.aggregate_sig = bls.aggregate_sigs(sigs)
print('Aggregated sig')
attestation_bitfield = get_empty_bitfield(len(committee_indices))
for i, attesting in enumerate(is_attesting):
if attesting:
attestation_bitfield = set_voted(attestation_bitfield, i)
attestation.attester_bitfield = attestation_bitfield
print('Aggregate bitfield:',
bin(int.from_bytes(attestation_bitfield, 'big')))
attestations.append(attestation)
return attestations
def mock_make_attestations(parent_state, block, attester_share=0.8):
crystallized_state, active_state = parent_state
cycle_length = config['cycle_length']
in_cycle_slot_height = block.slot_number % cycle_length
indices = crystallized_state.shard_and_committee_for_slots[
cycle_length + in_cycle_slot_height]
print("Generating attestations for shards: %s" % len(indices))
proposer_index_in_committee, proposer_shard_id = get_proposer_position(
block,
crystallized_state,
config=config,
)
attestations = []
for shard_and_committee in indices:
shard_id = shard_and_committee.shard_id
committee_indices = shard_and_committee.committee
print("Generating attestation for shard %s" % shard_id)
print("Committee size %s" % len(committee_indices))
justified_slot = crystallized_state.last_justified_slot
justified_block_hash = active_state.chain.get_block_by_slot_number(
justified_slot).hash
# Create attestation
attestation = AttestationRecord(
slot=block.slot_number,
shard_id=shard_and_committee.shard_id,
oblique_parent_hashes=[],
shard_block_hash=blake(bytes(str(shard_id), 'utf-8')),
attester_bitfield=get_empty_bitfield(len(committee_indices)),
justified_slot=justified_slot,
justified_block_hash=justified_block_hash,
)
# fill with roughly attester share fraction of voters
is_attesting = [
i < attester_share * len(committee_indices)
for i in range(len(committee_indices))
]
# Proposer always attests
if shard_id == proposer_shard_id:
is_attesting[proposer_index_in_committee] = True
# Generating signatures and aggregating result
parent_hashes = get_hashes_to_sign(active_state, block, config)
message = blake(
attestation.slot.to_bytes(8, byteorder='big') +
b''.join(parent_hashes) +
shard_id.to_bytes(2, byteorder='big') +
attestation.shard_block_hash +
attestation.justified_slot.to_bytes(8, byteorder='big'))
sigs = [
bls.sign(message,
keymap[crystallized_state.validators[indice].pubkey])
for i, indice in enumerate(committee_indices)
if is_attesting[i]
]
attestation.aggregate_sig = bls.aggregate_sigs(sigs)
print('Aggregated sig')
attestation_bitfield = get_empty_bitfield(len(committee_indices))
for i, attesting in enumerate(is_attesting):
if attesting:
attestation_bitfield = set_voted(attestation_bitfield, i)
attestation.attester_bitfield = attestation_bitfield
print('Aggregate bitfield:',
bin(int.from_bytes(attestation_bitfield, 'big')))
attestations.append(attestation)
return attestations
def make_unfinished_block(parent_state,
parent,
skips,
attester_share=0.8,
crosslink_shards_and_shares=None):
if crosslink_shards_and_shares is None:
crosslink_shards_and_shares = []
crystallized_state, active_state = parent_state
parent_attestation = serialize(parent)
indices, proposer = get_attesters_and_proposer(
crystallized_state,
active_state,
skips,
config
)
print('Selected indices: %r' % indices)
print('Selected block proposer: %d' % proposer)
# Randomly pick indices to include
is_attesting = [random.random() < attester_share for _ in indices]
# Attestations
sigs = [
bls.sign(
parent_attestation,
keymap[crystallized_state.active_validators[indices[i]].pubkey]
)
for i, attesting in enumerate(is_attesting) if attesting
]
attestation_aggregate_sig = bls.aggregate_sigs(sigs)
print('Aggregated sig')
attestation_bitfield = get_empty_bitfield(len(indices))
for i, attesting in enumerate(is_attesting):
if attesting:
attestation_bitfield = set_voted(attestation_bitfield, i)
print('Aggregate bitfield:', bin(int.from_bytes(attestation_bitfield, 'big')))
# Randomly pick indices to include for crosslinks
shard_aggregate_votes = []
# The shards that are selected to be crosslinking
crosslink_shards = get_crosslink_shards(crystallized_state, config=config)
for shard, crosslinker_share in crosslink_shards_and_shares:
# Check if this shard is in the crosslink shards list
assert shard in crosslink_shards
print('Making crosslink in shard %d' % shard)
indices = get_crosslink_notaries(crystallized_state, shard, crosslink_shards=crosslink_shards, config=config)
print('Indices: %r' % indices)
is_notarizing = [random.random() < attester_share for _ in indices]
notary_bitfield = get_empty_bitfield(len(indices))
for i, notarizing in enumerate(is_notarizing):
if notarizing:
notary_bitfield = set_voted(notary_bitfield, i)
print('Bitfield:', bin(int.from_bytes(notary_bitfield, 'big')))
shard_block_hash = blake(bytes([shard]))
crosslink_attestation_hash = get_crosslink_aggvote_msg(
shard,
shard_block_hash,
crystallized_state
)
sigs = [
bls.sign(
crosslink_attestation_hash,
keymap[crystallized_state.active_validators[indices[i]].pubkey]
)
for i, notarizing in enumerate(is_notarizing) if notarizing
]
v = AggregateVote(
shard_id=shard,
shard_block_hash=shard_block_hash,
notary_bitfield=notary_bitfield,
aggregate_sig=list(bls.aggregate_sigs(sigs))
)
shard_aggregate_votes.append(v)
print('Added %d shard aggregate votes' % len(crosslink_shards_and_shares))
block = Block(
parent_hash=blake(parent_attestation),
skip_count=skips,
randao_reveal=blake(str(random.random()).encode('utf-8')),
attestation_bitfield=attestation_bitfield,
attestation_aggregate_sig=list(attestation_aggregate_sig),
shard_aggregate_votes=shard_aggregate_votes,
main_chain_ref=b'\x00'*32,
state_hash=b'\x00'*64
)
return block, proposer
def make_unfinished_block(parent_state,
parent,
skips,
attester_share=0.8,
crosslink_shards_and_shares=None):
if crosslink_shards_and_shares is None:
crosslink_shards_and_shares = []
crystallized_state, active_state = parent_state
parent_attestation = serialize(parent)
indices, proposer = get_attesters_and_proposer(crystallized_state,
active_state, skips,
config)
print('Selected indices: %r' % indices)
print('Selected block proposer: %d' % proposer)
# Randomly pick indices to include
bitfield = [
1 if random.random() < attester_share else 0 for i in indices
]
# Attestations
sigs = [
bls.sign(
parent_attestation, keymap[
crystallized_state.active_validators[indices[i]].pubkey])
for i in range(len(indices)) if bitfield[i]
]
attestation_aggregate_sig = bls.aggregate_sigs(sigs)
print('Aggregated sig')
attestation_bitfield = bytearray((len(bitfield) - 1) // 8 + 1)
for i, b in enumerate(bitfield):
attestation_bitfield[i // 8] ^= (128 >> (i % 8)) * b
print('Aggregate bitfield:',
bin(int.from_bytes(attestation_bitfield, 'big')))
# Randomly pick indices to include for crosslinks
shard_aggregate_votes = []
# The shards that are selected to be crosslinking
crosslink_shards = get_crosslink_shards(crystallized_state,
config=config)
for shard, crosslinker_share in crosslink_shards_and_shares:
# Check if this shard is in the crosslink shards list
assert shard in crosslink_shards
print('Making crosslink in shard %d' % shard)
indices = get_crosslink_notaries(crystallized_state,
shard,
crosslink_shards=crosslink_shards,
config=config)
print('Indices: %r' % indices)
bitfield = [
1 if random.random() < crosslinker_share else 0
for i in indices
]
bitmask = bytearray((len(bitfield) + 7) // 8)
for i, b in enumerate(bitfield):
bitmask[i // 8] ^= (128 >> (i % 8)) * b
print('Bitmask:', bin(int.from_bytes(bitmask, 'big')))
shard_block_hash = blake(bytes([shard]))
crosslink_attestation_hash = get_crosslink_aggvote_msg(
shard, shard_block_hash, crystallized_state)
sigs = [
bls.sign(
crosslink_attestation_hash,
keymap[crystallized_state.active_validators[
indices[i]].pubkey]) for i in range(len(indices))
if bitfield[i]
]
v = AggregateVote(shard_id=shard,
shard_block_hash=shard_block_hash,
signer_bitmask=bitmask,
aggregate_sig=list(bls.aggregate_sigs(sigs)))
shard_aggregate_votes.append(v)
print('Added %d shard aggregate votes' %
len(crosslink_shards_and_shares))
block = Block(
parent_hash=blake(parent_attestation),
skip_count=skips,
randao_reveal=blake(str(random.random()).encode('utf-8')),
attestation_bitfield=attestation_bitfield,
attestation_aggregate_sig=list(attestation_aggregate_sig),
shard_aggregate_votes=shard_aggregate_votes,
main_chain_ref=b'\x00' * 32,
state_hash=b'\x00' * 64)
return block, proposer
def test_signature_aggregation(msg, privkeys):
sigs = [sign(msg, k) for k in privkeys]
pubs = [privtopub(k) for k in privkeys]
aggsig = aggregate_sigs(sigs)
aggpub = aggregate_pubs(pubs)
assert verify(msg, aggpub, aggsig)