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Merge branch 'master' into next-epoch-shuffling

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Danny Ryan 2019-01-30 11:06:50 -08:00
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specs/core/0_beacon-chain.md
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@ -26,7 +26,7 @@
- [`ProposerSlashing`](#proposerslashing)
- [Attester slashings](#attester-slashings)
- [`AttesterSlashing`](#attesterslashing)
- [`SlashableVote`](#slashablevote)
- [`SlashableAttestation`](#slashableattestation)
- [Attestations](#attestations)
- [`Attestation`](#attestation)
- [`AttestationData`](#attestationdata)
@ -80,7 +80,7 @@
- [`get_domain`](#get_domain)
- [`get_bitfield_bit`](#get_bitfield_bit)
- [`verify_bitfield`](#verify_bitfield)
- [`verify_slashable_vote`](#verify_slashable_vote)
- [`verify_slashable_attestation`](#verify_slashable_attestation)
- [`is_double_vote`](#is_double_vote)
- [`is_surround_vote`](#is_surround_vote)
- [`integer_squareroot`](#integer_squareroot)
@ -300,23 +300,23 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git
```python
{
# First batch of votes
'slashable_vote_1': SlashableVote,
# Second batch of votes
'slashable_vote_2': SlashableVote,
# First slashable attestation
'slashable_attestation_1': SlashableAttestation,
# Second slashable attestation
'slashable_attestation_2': SlashableAttestation,
}
```
##### `SlashableVote`
##### `SlashableAttestation`
```python
{
# Validator indices
'validator_indices': '[uint64]',
# Custody bitfield
'custody_bitfield': 'bytes',
'validator_indices': ['uint64'],
# Attestation data
'data': AttestationData,
# Custody bitfield
'custody_bitfield': 'bytes',
# Aggregate signature
'aggregate_signature': 'bytes96',
}
@ -328,10 +328,10 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git
```python
{
# Attestation data
'data': AttestationData,
# Attester aggregation bitfield
'aggregation_bitfield': 'bytes',
# Attestation data
'data': AttestationData,
# Custody bitfield
'custody_bitfield': 'bytes',
# BLS aggregate signature
@ -488,7 +488,6 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git
'validator_registry': [Validator],
'validator_balances': ['uint64'],
'validator_registry_update_epoch': 'uint64',
'validator_registry_exit_count': 'uint64',
# Randomness and committees
'latest_randao_mixes': ['bytes32'],
@ -535,8 +534,6 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git
'withdrawal_epoch': 'uint64',
# Epoch when validator was penalized
'penalized_epoch': 'uint64',
# Exit counter when validator exited
'exit_count': 'uint64',
# Status flags
'status_flags': 'uint64',
}
@ -557,14 +554,14 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git
```python
{
# Signed data
'data': AttestationData,
# Attester aggregation bitfield
'aggregation_bitfield': 'bytes',
# Attestation data
'data': AttestationData,
# Custody bitfield
'custody_bitfield': 'bytes',
# Slot the attestation was included
'slot_included': 'uint64',
# Inclusion slot
'inclusion_slot': 'uint64',
}
```
@ -636,6 +633,9 @@ Note: We aim to migrate to a S[T/N]ARK-friendly hash function in a future Ethere
```python
def slot_to_epoch(slot: SlotNumber) -> EpochNumber:
"""
Return the epoch number of the given ``slot``.
"""
return slot // EPOCH_LENGTH
```
@ -643,6 +643,9 @@ def slot_to_epoch(slot: SlotNumber) -> EpochNumber:
```python
def get_current_epoch(state: BeaconState) -> EpochNumber:
"""
Return the current epoch of the given ``state``.
"""
return slot_to_epoch(state.slot)
```
@ -650,6 +653,9 @@ def get_current_epoch(state: BeaconState) -> EpochNumber:
```python
def get_epoch_start_slot(epoch: EpochNumber) -> SlotNumber:
"""
Return the starting slot of the given ``epoch``.
"""
return epoch * EPOCH_LENGTH
```
@ -657,7 +663,7 @@ def get_epoch_start_slot(epoch: EpochNumber) -> SlotNumber:
```python
def is_active_validator(validator: Validator, epoch: EpochNumber) -> bool:
"""
Checks if ``validator`` is active.
Check if ``validator`` is active.
"""
return validator.activation_epoch <= epoch < validator.exit_epoch
```
@ -667,7 +673,7 @@ def is_active_validator(validator: Validator, epoch: EpochNumber) -> bool:
```python
def get_active_validator_indices(validators: List[Validator], epoch: EpochNumber) -> List[ValidatorIndex]:
"""
Gets indices of active validators from ``validators``.
Get indices of active validators from ``validators``.
"""
return [i for i, v in enumerate(validators) if is_active_validator(v, epoch)]
```
@ -677,7 +683,7 @@ def get_active_validator_indices(validators: List[Validator], epoch: EpochNumber
```python
def shuffle(values: List[Any], seed: Bytes32) -> List[Any]:
"""
Returns the shuffled ``values`` with ``seed`` as entropy.
Return the shuffled ``values`` with ``seed`` as entropy.
"""
values_count = len(values)
@ -743,6 +749,9 @@ def split(values: List[Any], split_count: int) -> List[List[Any]]:
```python
def get_epoch_committee_count(active_validator_count: int) -> int:
"""
Return the number of committees in one epoch.
"""
return max(
1,
min(
@ -759,8 +768,8 @@ def get_shuffling(seed: Bytes32,
validators: List[Validator],
epoch: EpochNumber) -> List[List[ValidatorIndex]]
"""
Shuffles ``validators`` into crosslink committees seeded by ``seed`` and ``epoch``.
Returns a list of ``committees_per_epoch`` committees where each
Shuffle ``validators`` into crosslink committees seeded by ``seed`` and ``epoch``.
Return a list of ``committees_per_epoch`` committees where each
committee is itself a list of validator indices.
"""
@ -784,6 +793,9 @@ def get_shuffling(seed: Bytes32,
```python
def get_previous_epoch_committee_count(state: BeaconState) -> int:
"""
Return the number of committees in the previous epoch of the given ``state``.
"""
previous_active_validators = get_active_validator_indices(
state.validator_registry,
state.previous_calculation_epoch,
@ -795,6 +807,9 @@ def get_previous_epoch_committee_count(state: BeaconState) -> int:
```python
def get_current_epoch_committee_count(state: BeaconState) -> int:
"""
Return the number of committees in the current epoch of the given ``state``.
"""
current_active_validators = get_active_validator_indices(
state.validator_registry,
state.current_calculation_epoch,
@ -820,7 +835,7 @@ def get_crosslink_committees_at_slot(state: BeaconState,
slot: SlotNumber,
registry_change=False: bool) -> List[Tuple[List[ValidatorIndex], ShardNumber]]:
"""
Returns the list of ``(committee, shard)`` tuples for the ``slot``.
Return the list of ``(committee, shard)`` tuples for the ``slot``.
Note: There are two possible shufflings for crosslink committees for a
``slot`` in the next epoch -- with and without a `registry_change`
@ -884,7 +899,7 @@ def get_crosslink_committees_at_slot(state: BeaconState,
def get_block_root(state: BeaconState,
slot: SlotNumber) -> Bytes32:
"""
Returns the block root at a recent ``slot``.
Return the block root at a recent ``slot``.
"""
assert state.slot <= slot + LATEST_BLOCK_ROOTS_LENGTH
assert slot < state.slot
@ -899,7 +914,7 @@ def get_block_root(state: BeaconState,
def get_randao_mix(state: BeaconState,
epoch: EpochNumber) -> Bytes32:
"""
Returns the randao mix at a recent ``epoch``.
Return the randao mix at a recent ``epoch``.
"""
assert get_current_epoch(state) - LATEST_RANDAO_MIXES_LENGTH < epoch <= get_current_epoch(state)
return state.latest_randao_mixes[epoch % LATEST_RANDAO_MIXES_LENGTH]
@ -911,7 +926,7 @@ def get_randao_mix(state: BeaconState,
def get_active_index_root(state: BeaconState,
epoch: EpochNumber) -> Bytes32:
"""
Returns the index root at a recent ``epoch``.
Return the index root at a recent ``epoch``.
"""
assert get_current_epoch(state) - LATEST_INDEX_ROOTS_LENGTH + ENTRY_EXIT_DELAY < epoch <= get_current_epoch(state) + ENTRY_EXIT_DELAY
return state.latest_index_roots[epoch % LATEST_INDEX_ROOTS_LENGTH]
@ -938,7 +953,7 @@ def generate_seed(state: BeaconState,
def get_beacon_proposer_index(state: BeaconState,
slot: SlotNumber) -> ValidatorIndex:
"""
Returns the beacon proposer index for the ``slot``.
Return the beacon proposer index for the ``slot``.
"""
first_committee, _ = get_crosslink_committees_at_slot(state, slot)[0]
return first_committee[slot % len(first_committee)]
@ -965,7 +980,7 @@ def get_attestation_participants(state: BeaconState,
attestation_data: AttestationData,
bitfield: bytes) -> List[ValidatorIndex]:
"""
Returns the participant indices at for the ``attestation_data`` and ``bitfield``.
Return the participant indices at for the ``attestation_data`` and ``bitfield``.
"""
# Find the committee in the list with the desired shard
crosslink_committees = get_crosslink_committees_at_slot(state, attestation_data.slot)
@ -1006,7 +1021,7 @@ def is_power_of_two(value: int) -> bool:
```python
def get_effective_balance(state: State, index: ValidatorIndex) -> Gwei:
"""
Returns the effective balance (also known as "balance at stake") for a ``validator`` with the given ``index``.
Return the effective balance (also known as "balance at stake") for a ``validator`` with the given ``index``.
"""
return min(state.validator_balances[index], MAX_DEPOSIT_AMOUNT)
```
@ -1016,6 +1031,9 @@ def get_effective_balance(state: State, index: ValidatorIndex) -> Gwei:
```python
def get_fork_version(fork: Fork,
epoch: EpochNumber) -> int:
"""
Return the fork version of the given ``epoch``.
"""
if epoch < fork.epoch:
return fork.previous_version
else:
@ -1028,10 +1046,11 @@ def get_fork_version(fork: Fork,
def get_domain(fork: Fork,
epoch: EpochNumber,
domain_type: int) -> int:
return get_fork_version(
fork,
epoch,
) * 2**32 + domain_type
"""
Get the domain number that represents the fork meta and signature domain.
"""
fork_version = get_fork_version(fork, epoch)
return fork_version * 2**32 + domain_type
```
### `get_bitfield_bit`
@ -1061,33 +1080,33 @@ def verify_bitfield(bitfield: bytes, committee_size: int) -> bool:
return True
```
### `verify_slashable_vote`
### `verify_slashable_attestation`
```python
def verify_slashable_vote(state: BeaconState, slashable_vote: SlashableVote) -> bool:
def verify_slashable_attestation(state: BeaconState, slashable_attestation: SlashableAttestation) -> bool:
"""
Verify validity of ``slashable_vote`` fields.
Verify validity of ``slashable_attestation`` fields.
"""
if slashable_vote.custody_bitfield != b'\x00' * len(slashable_vote.custody_bitfield): # [TO BE REMOVED IN PHASE 1]
if slashable_attestation.custody_bitfield != b'\x00' * len(slashable_attestation.custody_bitfield): # [TO BE REMOVED IN PHASE 1]
return False
if len(slashable_vote.validator_indices) == 0:
if len(slashable_attestation.validator_indices) == 0:
return False
for i in range(len(slashable_vote.validator_indices) - 1):
if slashable_vote.validator_indices[i] >= slashable_vote.validator_indices[i + 1]:
for i in range(len(slashable_attestation.validator_indices) - 1):
if slashable_attestation.validator_indices[i] >= slashable_attestation.validator_indices[i + 1]:
return False
if not verify_bitfield(slashable_vote.custody_bitfield, len(slashable_vote.validator_indices)):
if not verify_bitfield(slashable_attestation.custody_bitfield, len(slashable_attestation.validator_indices)):
return False
if len(slashable_vote.validator_indices) > MAX_INDICES_PER_SLASHABLE_VOTE:
if len(slashable_attestation.validator_indices) > MAX_INDICES_PER_SLASHABLE_VOTE:
return False
custody_bit_0_indices = []
custody_bit_1_indices = []
for i, validator_index in enumerate(slashable_vote.validator_indices):
if get_bitfield_bit(slashable_vote.custody_bitfield, i) == 0b0:
for i, validator_index in enumerate(slashable_attestation.validator_indices):
if get_bitfield_bit(slashable_attestation.custody_bitfield, i) == 0b0:
custody_bit_0_indices.append(validator_index)
else:
custody_bit_1_indices.append(validator_index)
@ -1098,10 +1117,10 @@ def verify_slashable_vote(state: BeaconState, slashable_vote: SlashableVote) ->
bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in custody_bit_1_indices]),
],
messages=[
hash_tree_root(AttestationDataAndCustodyBit(attestation_data=slashable_vote.data, custody_bit=0b0)),
hash_tree_root(AttestationDataAndCustodyBit(attestation_data=slashable_vote.data, custody_bit=0b1)),
hash_tree_root(AttestationDataAndCustodyBit(data=slashable_attestation.data, custody_bit=0b0)),
hash_tree_root(AttestationDataAndCustodyBit(data=slashable_attestation.data, custody_bit=0b1)),
],
signature=slashable_vote.aggregate_signature,
signature=slashable_attestation.aggregate_signature,
domain=get_domain(
state.fork,
slot_to_epoch(vote_data.data.slot),
@ -1114,11 +1133,9 @@ def verify_slashable_vote(state: BeaconState, slashable_vote: SlashableVote) ->
```python
def is_double_vote(attestation_data_1: AttestationData,
attestation_data_2: AttestationData) -> bool
attestation_data_2: AttestationData) -> bool:
"""
Assumes ``attestation_data_1`` is distinct from ``attestation_data_2``.
Returns True if the provided ``AttestationData`` are slashable
due to a 'double vote'.
Check if ``attestation_data_1`` and ``attestation_data_2`` have the same target.
"""
target_epoch_1 = slot_to_epoch(attestation_data_1.slot)
target_epoch_2 = slot_to_epoch(attestation_data_2.slot)
@ -1131,11 +1148,7 @@ def is_double_vote(attestation_data_1: AttestationData,
def is_surround_vote(attestation_data_1: AttestationData,
attestation_data_2: AttestationData) -> bool:
"""
Assumes ``attestation_data_1`` is distinct from ``attestation_data_2``.
Returns True if the provided ``AttestationData`` are slashable
due to a 'surround vote'.
Note: parameter order matters as this function only checks
that ``attestation_data_1`` surrounds ``attestation_data_2``.
Check if ``attestation_data_1`` surrounds ``attestation_data_2``.
"""
source_epoch_1 = attestation_data_1.justified_epoch
source_epoch_2 = attestation_data_2.justified_epoch
@ -1191,6 +1204,9 @@ def validate_proof_of_possession(state: BeaconState,
pubkey: BLSPubkey,
proof_of_possession: BLSSignature,
withdrawal_credentials: Bytes32) -> bool:
"""
Verify the given ``proof_of_possession``.
"""
proof_of_possession_data = DepositInput(
pubkey=pubkey,
withdrawal_credentials=withdrawal_credentials,
@ -1242,7 +1258,6 @@ def process_deposit(state: BeaconState,
exit_epoch=FAR_FUTURE_EPOCH,
withdrawal_epoch=FAR_FUTURE_EPOCH,
penalized_epoch=FAR_FUTURE_EPOCH,
exit_count=0,
status_flags=0,
)
@ -1264,16 +1279,24 @@ Note: All functions in this section mutate `state`.
#### `activate_validator`
```python
def activate_validator(state: BeaconState, index: ValidatorIndex, genesis: bool) -> None:
def activate_validator(state: BeaconState, index: ValidatorIndex, is_genesis: bool) -> None:
"""
Activate the validator of the given ``index``.
Note that this function mutates ``state``.
"""
validator = state.validator_registry[index]
validator.activation_epoch = GENESIS_EPOCH if genesis else get_entry_exit_effect_epoch(get_current_epoch(state))
validator.activation_epoch = GENESIS_EPOCH if is_genesis else get_entry_exit_effect_epoch(get_current_epoch(state))
```
#### `initiate_validator_exit`
```python
def initiate_validator_exit(state: BeaconState, index: ValidatorIndex) -> None:
"""
Initiate the validator of the given ``index``.
Note that this function mutates ``state``.
"""
validator = state.validator_registry[index]
validator.status_flags |= INITIATED_EXIT
```
@ -1282,6 +1305,10 @@ def initiate_validator_exit(state: BeaconState, index: ValidatorIndex) -> None:
```python
def exit_validator(state: BeaconState, index: ValidatorIndex) -> None:
"""
Exit the validator of the given ``index``.
Note that this function mutates ``state``.
"""
validator = state.validator_registry[index]
# The following updates only occur if not previous exited
@ -1289,15 +1316,16 @@ def exit_validator(state: BeaconState, index: ValidatorIndex) -> None:
return
validator.exit_epoch = get_entry_exit_effect_epoch(get_current_epoch(state))
state.validator_registry_exit_count += 1
validator.exit_count = state.validator_registry_exit_count
```
#### `penalize_validator`
```python
def penalize_validator(state: BeaconState, index: ValidatorIndex) -> None:
"""
Penalize the validator of the given ``index``.
Note that this function mutates ``state``.
"""
exit_validator(state, index)
validator = state.validator_registry[index]
state.latest_penalized_balances[get_current_epoch(state) % LATEST_PENALIZED_EXIT_LENGTH] += get_effective_balance(state, index)
@ -1313,6 +1341,10 @@ def penalize_validator(state: BeaconState, index: ValidatorIndex) -> None:
```python
def prepare_validator_for_withdrawal(state: BeaconState, index: ValidatorIndex) -> None:
"""
Set the validator with the given ``index`` with ``WITHDRAWABLE`` flag.
Note that this function mutates ``state``.
"""
validator = state.validator_registry[index]
validator.status_flags |= WITHDRAWABLE
```
@ -1441,6 +1473,9 @@ A valid block with slot `GENESIS_SLOT` (a "genesis block") has the following val
def get_initial_beacon_state(initial_validator_deposits: List[Deposit],
genesis_time: int,
latest_eth1_data: Eth1Data) -> BeaconState:
"""
Get the initial ``BeaconState``.
"""
state = BeaconState(
# Misc
slot=GENESIS_SLOT,
@ -1455,7 +1490,6 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit],
validator_registry=[],
validator_balances=[],
validator_registry_update_epoch=GENESIS_EPOCH,
validator_registry_exit_count=0,
# Randomness and committees
latest_randao_mixes=[ZERO_HASH for _ in range(LATEST_RANDAO_MIXES_LENGTH)],
@ -1498,7 +1532,7 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit],
# Process initial activations
for validator_index, _ in enumerate(state.validator_registry):
if get_effective_balance(state, validator_index) >= MAX_DEPOSIT_AMOUNT:
activate_validator(state, validator_index, True)
activate_validator(state, validator_index, is_genesis=True)
genesis_active_index_root = hash_tree_root(get_active_validator_indices(state, GENESIS_EPOCH))
for index in range(LATEST_INDEX_ROOTS_LENGTH):
@ -1539,6 +1573,9 @@ The beacon chain fork choice rule is a hybrid that combines justification and fi
```python
def get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBlock:
"""
Get the ancestor of ``block`` with slot number ``slot``; return ``None`` if not found.
"""
if block.slot == slot:
return block
elif block.slot < slot:
@ -1555,6 +1592,9 @@ def get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBl
```python
def lmd_ghost(store: Store, start_state: BeaconState, start_block: BeaconBlock) -> BeaconBlock:
"""
Execute the LMD-GHOST algorithm to find the head ``BeaconBlock``.
"""
validators = start_state.validator_registry
active_validators = [
validators[i]
@ -1654,15 +1694,15 @@ Verify that `len(block.body.attester_slashings) <= MAX_ATTESTER_SLASHINGS`.
For each `attester_slashing` in `block.body.attester_slashings`:
* Let `slashable_vote_1 = attester_slashing.slashable_vote_1`.
* Let `slashable_vote_2 = attester_slashing.slashable_vote_2`.
* Let `intersection = [x for x in slashable_vote_1.validator_indices if x in slashable_vote_2.validator_indices]`.
* Verify that `len(intersection) >= 1`.
* Verify that `slashable_vote_1.data != slashable_vote_2.data`.
* Verify that `is_double_vote(slashable_vote_1.data, slashable_vote_2.data)` or `is_surround_vote(slashable_vote_1.data, slashable_vote_2.data)`.
* Verify that `verify_slashable_vote(state, slashable_vote_1)`.
* Verify that `verify_slashable_vote(state, slashable_vote_2)`.
* For each [validator](#dfn-validator) index `i` in `intersection` run `penalize_validator(state, i)` if `state.validator_registry[i].penalized_epoch > get_current_epoch(state)`.
* Let `slashable_attestation_1 = attester_slashing.slashable_attestation_1`.
* Let `slashable_attestation_2 = attester_slashing.slashable_attestation_2`.
* Verify that `slashable_attestation_1.data != slashable_attestation_2.data`.
* Verify that `is_double_vote(slashable_attestation_1.data, slashable_attestation_2.data)` or `is_surround_vote(slashable_attestation_1.data, slashable_attestation_2.data)`.
* Verify that `verify_slashable_attestation(state, slashable_attestation_1)`.
* Verify that `verify_slashable_attestation(state, slashable_attestation_2)`.
* Let `slashable_indices = [index for index in slashable_attestation_1.validator_indices if index in slashable_attestation_2.validator_indices and state.validator_registry[index].penalized_epoch > get_current_epoch(state)]`.
* Verify that `len(slashable_indices) >= 1`.
* Run `penalize_validator(state, index)` for each `index` in `slashable_indices`.
##### Attestations
@ -1703,7 +1743,7 @@ For each `attestation` in `block.body.attestations`:
```
* [TO BE REMOVED IN PHASE 1] Verify that `attestation.data.shard_block_root == ZERO_HASH`.
* Append `PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, custody_bitfield=attestation.custody_bitfield, slot_included=state.slot)` to `state.latest_attestations`.
* Append `PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, custody_bitfield=attestation.custody_bitfield, inclusion_slot=state.slot)` to `state.latest_attestations`.
##### Deposits
@ -1719,6 +1759,9 @@ For each `deposit` in `block.body.deposits`:
```python
def verify_merkle_branch(leaf: Bytes32, branch: List[Bytes32], depth: int, index: int, root: Bytes32) -> bool:
"""
Verify that the given ``leaf`` is on the merkle branch ``branch``.
"""
value = leaf
for i in range(depth):
if index // (2**i) % 2:
@ -1804,8 +1847,8 @@ For every `slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_s
Define the following helpers to process attestation inclusion rewards and inclusion distance reward/penalty. For every attestation `a` in `previous_epoch_attestations`:
* Let `inclusion_slot(state, index) = a.slot_included` for the attestation `a` where `index` is in `get_attestation_participants(state, a.data, a.aggregation_bitfield)`. If multiple attestations are applicable, the attestation with lowest `slot_included` is considered.
* Let `inclusion_distance(state, index) = a.slot_included - a.data.slot` where `a` is the above attestation.
* Let `inclusion_slot(state, index) = a.inclusion_slot` for the attestation `a` where `index` is in `get_attestation_participants(state, a.data, a.aggregation_bitfield)`. If multiple attestations are applicable, the attestation with lowest `inclusion_slot` is considered.
* Let `inclusion_distance(state, index) = a.inclusion_slot - a.data.slot` where `a` is the above attestation.
#### Eth1 data
@ -1859,7 +1902,7 @@ Case 1: `epochs_since_finality <= 4`:
* Expected FFG source:
* Any [validator](#dfn-validator) `index` in `previous_epoch_justified_attester_indices` gains `base_reward(state, index) * previous_epoch_justified_attesting_balance // previous_total_balance`.
* Any [active validator](#dfn-active-validator) `v` not in `previous_epoch_justified_attester_indices` loses `base_reward(state, index)`.
* Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_justified_attester_indices` loses `base_reward(state, index)`.
* Expected FFG target:
* Any [validator](#dfn-validator) `index` in `previous_epoch_boundary_attester_indices` gains `base_reward(state, index) * previous_epoch_boundary_attesting_balance // previous_total_balance`.
* Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_boundary_attester_indices` loses `base_reward(state, index)`.
@ -1948,7 +1991,7 @@ def update_validator_registry(state: BeaconState) -> None:
break
# Activate validator
activate_validator(state, index, False)
activate_validator(state, index, is_genesis=False)
# Exit validators within the allowable balance churn
balance_churn = 0
@ -1985,17 +2028,21 @@ Regardless of whether or not a validator set change happens, run the following:
```python
def process_penalties_and_exits(state: BeaconState) -> None:
"""
Process the penalties and prepare the validators who are eligible to withdrawal.
Note that this function mutates ``state``.
"""
current_epoch = get_current_epoch(state)
# The active validators
active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch)
# The total effective balance of active validators
total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices])
total_balance = sum(get_effective_balance(state, i) for i in active_validator_indices)
for index, validator in enumerate(state.validator_registry):
if current_epoch == validator.penalized_epoch + LATEST_PENALIZED_EXIT_LENGTH // 2:
e = current_epoch % LATEST_PENALIZED_EXIT_LENGTH
total_at_start = state.latest_penalized_balances[(e + 1) % LATEST_PENALIZED_EXIT_LENGTH]
total_at_end = state.latest_penalized_balances[e]
epoch_index = current_epoch % LATEST_PENALIZED_EXIT_LENGTH
total_at_start = state.latest_penalized_balances[(epoch_index + 1) % LATEST_PENALIZED_EXIT_LENGTH]
total_at_end = state.latest_penalized_balances[epoch_index]
total_penalties = total_at_end - total_at_start
penalty = get_effective_balance(state, index) * min(total_penalties * 3, total_balance) // total_balance
state.validator_balances[index] -= penalty
@ -2010,7 +2057,8 @@ def process_penalties_and_exits(state: BeaconState) -> None:
all_indices = list(range(len(state.validator_registry)))
eligible_indices = filter(eligible, all_indices)
sorted_indices = sorted(eligible_indices, key=lambda index: state.validator_registry[index].exit_count)
# Sort in order of exit epoch, and validators that exit within the same epoch exit in order of validator index
sorted_indices = sorted(eligible_indices, key=lambda index: state.validator_registry[index].exit_epoch)
withdrawn_so_far = 0
for index in sorted_indices:
prepare_validator_for_withdrawal(state, index)

16
specs/validator/0_beacon-chain-validator.md
View File

@ -43,11 +43,11 @@ __NOTICE__: This document is a work-in-progress for researchers and implementers
- [Epoch boundary root](#epoch-boundary-root)
- [Shard block root](#shard-block-root)
- [Latest crosslink root](#latest-crosslink-root)
- [Justified slot](#justified-slot)
- [Justified epoch](#justified-epoch)
- [Justified block root](#justified-block-root)
- [Construct attestation](#construct-attestation)
- [Data](#data)
- [Participation bitfield](#participation-bitfield)
- [Aggregation bitfield](#aggregation-bitfield)
- [Custody bitfield](#custody-bitfield)
- [Aggregate signature](#aggregate-signature)
- [Responsibility lookahead](#responsibility-lookahead)
@ -252,7 +252,7 @@ Set `attestation_data.slot = slot` where `slot` is the current slot of which the
##### Shard
Set `attestation_data.shard = shard` where `shard` is the shard associated with the validator's committee defined by `get_shard_committees_at_slot`.
Set `attestation_data.shard = shard` where `shard` is the shard associated with the validator's committee defined by `get_crosslink_committees_at_slot`.
##### Beacon block root
@ -274,15 +274,15 @@ _Note:_ This is a stub for phase 0.
Set `attestation_data.latest_crosslink_root = state.latest_crosslinks[shard].shard_block_root` where `state` is the beacon state at `head` and `shard` is the validator's assigned shard.
##### Justified slot
##### Justified epoch
Set `attestation_data.justified_slot = state.justified_slot` where `state` is the beacon state at `head`.
Set `attestation_data.justified_epoch = state.justified_epoch` where `state` is the beacon state at `head`.
##### Justified block root
Set `attestation_data.justified_block_root = hash_tree_root(justified_block)` where `justified_block` is the block at `state.justified_slot` in the chain defined by `head`.
Set `attestation_data.justified_block_root = hash_tree_root(justified_block)` where `justified_block` is the block at `state.justified_epoch` in the chain defined by `head`.
_Note:_ This can be looked up in the state using `get_block_root(state, justified_slot)`.
_Note:_ This can be looked up in the state using `get_block_root(state, justified_epoch)`.
#### Construct attestation
@ -292,7 +292,7 @@ Next the validator creates `attestation`, an [`Attestation`](https://github.com/
Set `attestation.data = attestation_data` where `attestation_data` is the `AttestationData` object defined in the previous section, [attestation data](#attestation-data).
##### Participation bitfield
##### Aggregation bitfield
* Let `aggregation_bitfield` be a byte array filled with zeros of length `(len(committee) + 7) // 8`.
* Let `index_into_committee` be the index into the validator's `committee` at which `validator_index` is located.