Merge pull request #949 from ethereum/JustinDrake-patch-14

Revamp balances and incentivisation
2026-02-02 16:45:01 -05:00 · 2019-04-24 11:35:27 -06:00
parent 6c7ab5905b 20d65e040b
commit ade74f0be0
11 changed files with 191 additions and 263 deletions
--- a/specs/core/0_beacon-chain.md
+++ b/specs/core/0_beacon-chain.md
@@ -58,8 +58,6 @@
        - [`is_active_validator`](#is_active_validator)
        - [`is_slashable_validator`](#is_slashable_validator)
        - [`get_active_validator_indices`](#get_active_validator_indices)
-        - [`get_balance`](#get_balance)
-        - [`set_balance`](#set_balance)
        - [`increase_balance`](#increase_balance)
        - [`decrease_balance`](#decrease_balance)
        - [`get_permuted_index`](#get_permuted_index)
@@ -68,6 +66,7 @@
        - [`get_shard_delta`](#get_shard_delta)
        - [`compute_committee`](#compute_committee)
        - [`get_crosslink_committees_at_slot`](#get_crosslink_committees_at_slot)
+        - [`get_block_root_at_slot`](#get_block_root_at_slot)
        - [`get_block_root`](#get_block_root)
        - [`get_state_root`](#get_state_root)
        - [`get_randao_mix`](#get_randao_mix)
@@ -78,7 +77,6 @@
        - [`get_attesting_indices`](#get_attesting_indices)
        - [`int_to_bytes1`, `int_to_bytes2`, ...](#int_to_bytes1-int_to_bytes2-)
        - [`bytes_to_int`](#bytes_to_int)
-        - [`get_effective_balance`](#get_effective_balance)
        - [`get_total_balance`](#get_total_balance)
        - [`get_domain`](#get_domain)
        - [`get_bitfield_bit`](#get_bitfield_bit)
@@ -175,6 +173,7 @@ These configurations are updated for releases, but may be out of sync during `de
 | `MAX_INDICES_PER_ATTESTATION` | `2**12` (= 4,096) |
 | `MIN_PER_EPOCH_CHURN_LIMIT` | `2**2` (= 4) |
 | `CHURN_LIMIT_QUOTIENT` | `2**16` (= 65,536) |
+| `BASE_REWARDS_PER_EPOCH` | `5` |
 | `SHUFFLE_ROUND_COUNT` | 90 |

 * For the safety of crosslinks `TARGET_COMMITTEE_SIZE` exceeds [the recommended minimum committee size of 111](https://vitalik.ca/files/Ithaca201807_Sharding.pdf); with sufficient active validators (at least `SLOTS_PER_EPOCH * TARGET_COMMITTEE_SIZE`), the shuffling algorithm ensures committee sizes of at least `TARGET_COMMITTEE_SIZE`. (Unbiasable randomness with a Verifiable Delay Function (VDF) will improve committee robustness and lower the safe minimum committee size.)
@@ -193,7 +192,7 @@ These configurations are updated for releases, but may be out of sync during `de
 | `MIN_DEPOSIT_AMOUNT` | `2**0 * 10**9` (= 1,000,000,000) | Gwei |
 | `MAX_EFFECTIVE_BALANCE` | `2**5 * 10**9` (= 32,000,000,000) | Gwei |
 | `EJECTION_BALANCE` | `2**4 * 10**9` (= 16,000,000,000) | Gwei |
-| `HIGH_BALANCE_INCREMENT` | `2**0 * 10**9` (= 1,000,000,000) | Gwei |
+| `EFFECTIVE_BALANCE_INCREMENT` | `2**0 * 10**9` (= 1,000,000,000) | Gwei |

 ### Initial values

@@ -219,6 +218,7 @@ These configurations are updated for releases, but may be out of sync during `de
 | `MIN_VALIDATOR_WITHDRAWABILITY_DELAY` | `2**8` (= 256) | epochs | ~27 hours |
 | `PERSISTENT_COMMITTEE_PERIOD` | `2**11` (= 2,048)  | epochs | 9 days  |
 | `MAX_CROSSLINK_EPOCHS` | `2**6` (= 64) | epochs | ~7 hours |
+| `MIN_EPOCHS_TO_INACTIVITY_PENALTY` | `2**2` (= 4) | epochs | 25.6 minutes |

 * `MAX_CROSSLINK_EPOCHS` should be a small constant times `SHARD_COUNT // SLOTS_PER_EPOCH`

@@ -237,8 +237,8 @@ These configurations are updated for releases, but may be out of sync during `de
 | `BASE_REWARD_QUOTIENT` | `2**5` (= 32) |
 | `WHISTLEBLOWING_REWARD_QUOTIENT` | `2**9` (= 512) |
 | `PROPOSER_REWARD_QUOTIENT` | `2**3` (= 8) |
-| `INACTIVITY_PENALTY_QUOTIENT` | `2**24` (= 16,777,216) |
-| `MIN_PENALTY_QUOTIENT` | `2**5` (= 32) |
+| `INACTIVITY_PENALTY_QUOTIENT` | `2**25` (= 33,554,432) |
+| `MIN_SLASHING_PENALTY_QUOTIENT` | `2**5` (= 32) |

 * **The `BASE_REWARD_QUOTIENT` is NOT final. Once all other protocol details are finalized it will be adjusted, to target a theoretical maximum total issuance of `2**21` ETH per year if `2**27` ETH is validating (and therefore `2**20` per year if `2**25` ETH is validating, etc etc)**
 * The `INACTIVITY_PENALTY_QUOTIENT` equals `INVERSE_SQRT_E_DROP_TIME**2` where `INVERSE_SQRT_E_DROP_TIME := 2**12 epochs` (~18 days) is the time it takes the inactivity penalty to reduce the balance of non-participating [validators](#dfn-validator) to about `1/sqrt(e) ~= 60.6%`. Indeed, the balance retained by offline [validators](#dfn-validator) after `n` epochs is about `(1 - 1/INACTIVITY_PENALTY_QUOTIENT)**(n**2/2)` so after `INVERSE_SQRT_E_DROP_TIME` epochs it is roughly `(1 - 1/INACTIVITY_PENALTY_QUOTIENT)**(INACTIVITY_PENALTY_QUOTIENT/2) ~= 1/sqrt(e)`.
@@ -401,8 +401,8 @@ The types are defined topologically to aid in facilitating an executable version
    'withdrawable_epoch': 'uint64',
    # Was the validator slashed
    'slashed': 'bool',
-    # Rounded balance
-    'high_balance': 'uint64'
+    # Effective balance
+    'effective_balance': 'uint64',
 }
 ```

@@ -416,6 +416,8 @@ The types are defined topologically to aid in facilitating an executable version
    'data': AttestationData,
    # Inclusion slot
    'inclusion_slot': 'uint64',
+    # Proposer index
+    'proposer_index': 'uint64',
 }
 ```

@@ -678,6 +680,7 @@ def get_epoch_start_slot(epoch: Epoch) -> Slot:
 ```

 ### `is_active_validator`
+
 ```python
 def is_active_validator(validator: Validator, epoch: Epoch) -> bool:
    """
@@ -687,15 +690,14 @@ def is_active_validator(validator: Validator, epoch: Epoch) -> bool:
 ```

 ### `is_slashable_validator`
+
 ```python
 def is_slashable_validator(validator: Validator, epoch: Epoch) -> bool:
    """
    Check if ``validator`` is slashable.
    """
-    return (
-        validator.activation_epoch <= epoch < validator.withdrawable_epoch and
-        validator.slashed is False
-    )
+    return validator.slashed is False and (validator.activation_epoch <= epoch < validator.withdrawable_epoch)
+
 ```

 ### `get_active_validator_indices`
@@ -708,39 +710,14 @@ def get_active_validator_indices(state: BeaconState, epoch: Epoch) -> List[Valid
    return [i for i, v in enumerate(state.validator_registry) if is_active_validator(v, epoch)]
 ```

-### `get_balance`
-
-```python
-def get_balance(state: BeaconState, index: ValidatorIndex) -> Gwei:
-    """
-    Return the balance for a validator with the given ``index``.
-    """
-    return state.balances[index]
-```
-
-### `set_balance`
-
-```python
-def set_balance(state: BeaconState, index: ValidatorIndex, balance: Gwei) -> None:
-    """
-    Set the balance for a validator with the given ``index`` in both ``BeaconState``
-    and validator's rounded balance ``high_balance``.
-    """
-    validator = state.validator_registry[index]
-    HALF_INCREMENT = HIGH_BALANCE_INCREMENT // 2
-    if validator.high_balance > balance or validator.high_balance + 3 * HALF_INCREMENT < balance:
-        validator.high_balance = balance - balance % HIGH_BALANCE_INCREMENT
-    state.balances[index] = balance
-```
-
 ### `increase_balance`

 ```python
 def increase_balance(state: BeaconState, index: ValidatorIndex, delta: Gwei) -> None:
    """
-    Increase the balance for a validator with the given ``index`` by ``delta``.
+    Increase validator balance by ``delta``.
    """
-    set_balance(state, index, get_balance(state, index) + delta)
+    state.balances[index] += delta
 ```

 ### `decrease_balance`
@@ -748,11 +725,9 @@ def increase_balance(state: BeaconState, index: ValidatorIndex, delta: Gwei) ->
 ```python
 def decrease_balance(state: BeaconState, index: ValidatorIndex, delta: Gwei) -> None:
    """
-    Decrease the balance for a validator with the given ``index`` by ``delta``.
-    Set to ``0`` when underflow.
+    Decrease validator balance by ``delta`` with underflow protection.
    """
-    current_balance = get_balance(state, index)
-    set_balance(state, index, current_balance - delta if current_balance >= delta else 0)
+    state.balances[index] = 0 if delta > state.balances[index] else state.balances[index] - delta
 ```

 ### `get_permuted_index`
@@ -799,12 +774,12 @@ def get_epoch_committee_count(state: BeaconState, epoch: Epoch) -> int:
    """
    Return the number of committees at ``epoch``.
    """
-    active_validators = get_active_validator_indices(state, epoch)
+    active_validator_indices = get_active_validator_indices(state, epoch)
    return max(
        1,
        min(
            SHARD_COUNT // SLOTS_PER_EPOCH,
-            len(active_validators) // SLOTS_PER_EPOCH // TARGET_COMMITTEE_SIZE,
+            len(active_validator_indices) // SLOTS_PER_EPOCH // TARGET_COMMITTEE_SIZE,
        )
    ) * SLOTS_PER_EPOCH
 ```
@@ -838,7 +813,7 @@ def compute_committee(validator_indices: List[ValidatorIndex],
    ]
 ```

-**Note**: this definition and the next few definitions are highly inefficient as algorithms, as they re-calculate many sub-expressions. Production implementations are expected to appropriately use caching/memoization to avoid redoing work.
+Note: this definition and the next few definitions are highly inefficient as algorithms, as they re-calculate many sub-expressions. Production implementations are expected to appropriately use caching/memoization to avoid redoing work.

 ### `get_crosslink_committees_at_slot`

@@ -880,11 +855,11 @@ def get_crosslink_committees_at_slot(state: BeaconState,
    ]
 ```

-### `get_block_root`
+### `get_block_root_at_slot`

 ```python
-def get_block_root(state: BeaconState,
-                   slot: Slot) -> Bytes32:
+def get_block_root_at_slot(state: BeaconState,
+                           slot: Slot) -> Bytes32:
    """
    Return the block root at a recent ``slot``.
    """
@@ -892,7 +867,16 @@ def get_block_root(state: BeaconState,
    return state.latest_block_roots[slot % SLOTS_PER_HISTORICAL_ROOT]
 ```

-`get_block_root(_, s)` should always return `signing_root` of the block in the beacon chain at slot `s`, and `get_crosslink_committees_at_slot(_, s)` should not change unless the [validator](#dfn-validator) registry changes.
+### `get_block_root`
+
+```python
+def get_block_root(state: BeaconState,
+                   epoch: Epoch) -> Bytes32:
+    """
+    Return the block root at a recent ``epoch``.
+    """
+    return get_block_root_at_slot(state, get_epoch_start_slot(epoch))
+```

 ### `get_state_root`

@@ -905,6 +889,7 @@ def get_state_root(state: BeaconState,
    assert slot < state.slot <= slot + SLOTS_PER_HISTORICAL_ROOT
    return state.latest_state_roots[slot % SLOTS_PER_HISTORICAL_ROOT]
 ```
+
 ### `get_randao_mix`

 ```python
@@ -952,14 +937,15 @@ def get_beacon_proposer_index(state: BeaconState) -> ValidatorIndex:
    Return the beacon proposer index at ``state.slot``.
    """
    current_epoch = get_current_epoch(state)
-
    first_committee, _ = get_crosslink_committees_at_slot(state, state.slot)[0]
+    MAX_RANDOM_BYTE = 2**8 - 1
    i = 0
    while True:
-        candidate = first_committee[(current_epoch + i) % len(first_committee)]
+        candidate_index = first_committee[(current_epoch + i) % len(first_committee)]
        random_byte = hash(generate_seed(state, current_epoch) + int_to_bytes8(i // 32))[i % 32]
-        if get_effective_balance(state, candidate) * 256 > MAX_EFFECTIVE_BALANCE * random_byte:
-            return candidate
+        effective_balance = state.validator_registry[candidate_index].effective_balance
+        if effective_balance * MAX_RANDOM_BYTE >= MAX_EFFECTIVE_BALANCE * random_byte:
+            return candidate_index
        i += 1
 ```

@@ -1006,24 +992,14 @@ def bytes_to_int(data: bytes) -> int:
    return int.from_bytes(data, 'little')
 ```

-### `get_effective_balance`
-
-```python
-def get_effective_balance(state: BeaconState, index: ValidatorIndex) -> Gwei:
-    """
-    Return the effective balance (also known as "balance at stake") for a validator with the given ``index``.
-    """
-    return min(get_balance(state, index), MAX_EFFECTIVE_BALANCE)
-```
-
 ### `get_total_balance`

 ```python
-def get_total_balance(state: BeaconState, validators: List[ValidatorIndex]) -> Gwei:
+def get_total_balance(state: BeaconState, indices: List[ValidatorIndex]) -> Gwei:
    """
    Return the combined effective balance of an array of ``validators``.
    """
-    return sum([get_effective_balance(state, i) for i in validators])
+    return sum([state.validator_registry[index].effective_balance for index in indices])
 ```

 ### `get_domain`
@@ -1240,11 +1216,12 @@ def slash_validator(state: BeaconState, slashed_index: ValidatorIndex, whistlebl
    Slash the validator with index ``slashed_index``.
    Note that this function mutates ``state``.
    """
+    current_epoch = get_current_epoch(state)
    initiate_validator_exit(state, slashed_index)
    state.validator_registry[slashed_index].slashed = True
-    state.validator_registry[slashed_index].withdrawable_epoch = get_current_epoch(state) + LATEST_SLASHED_EXIT_LENGTH
-    slashed_balance = get_effective_balance(state, slashed_index)
-    state.latest_slashed_balances[get_current_epoch(state) % LATEST_SLASHED_EXIT_LENGTH] += slashed_balance
+    state.validator_registry[slashed_index].withdrawable_epoch = current_epoch + LATEST_SLASHED_EXIT_LENGTH
+    slashed_balance = state.validator_registry[slashed_index].effective_balance
+    state.latest_slashed_balances[current_epoch % LATEST_SLASHED_EXIT_LENGTH] += slashed_balance

    proposer_index = get_beacon_proposer_index(state)
    if whistleblower_index is None:
@@ -1327,7 +1304,7 @@ def get_genesis_beacon_state(genesis_validator_deposits: List[Deposit],

    # Process genesis activations
    for index, validator in enumerate(state.validator_registry):
-        if get_effective_balance(state, index) >= MAX_EFFECTIVE_BALANCE:
+        if validator.effective_balance >= MAX_EFFECTIVE_BALANCE:
            validator.activation_eligibility_epoch = GENESIS_EPOCH
            validator.activation_epoch = GENESIS_EPOCH

@@ -1395,12 +1372,10 @@ def lmd_ghost(store: Store, start_state: BeaconState, start_block: BeaconBlock)
    active_validator_indices = get_active_validator_indices(validators, slot_to_epoch(start_state.slot))
    attestation_targets = [(i, get_latest_attestation_target(store, i)) for i in active_validator_indices]

-    # Use the rounded-balance-with-hysteresis supplied by the protocol for fork
-    # choice voting. This reduces the number of recomputations that need to be
-    # made for optimized implementations that precompute and save data
+    # Use the effective balance for fork choice voting to reduce recomputations and save bandwidth
    def get_vote_count(block: BeaconBlock) -> int:
        return sum(
-            start_state.validator_registry[validator_index].high_balance
+            start_state.validator_registry[validator_index].effective_balance
            for validator_index, target in attestation_targets
            if get_ancestor(store, target, block.slot) == block
        )
@@ -1431,7 +1406,7 @@ Transition section notes:

 Beacon blocks that trigger unhandled Python exceptions (e.g. out-of-range list accesses) and failed `assert`s during the state transition are considered invalid.

-_Note_: If there are skipped slots between a block and its parent block, run the steps in the [state-root](#state-caching), [per-epoch](#per-epoch-processing), and [per-slot](#per-slot-processing) sections once for each skipped slot and then once for the slot containing the new block.
+Note: If there are skipped slots between a block and its parent block, run the steps in the [state-root](#state-caching), [per-epoch](#per-epoch-processing), and [per-slot](#per-slot-processing) sections once for each skipped slot and then once for the slot containing the new block.

 ### State caching

@@ -1461,13 +1436,30 @@ The steps below happen when `state.slot > GENESIS_SLOT and (state.slot + 1) % SL
 We define epoch transition helper functions:

 ```python
-def get_current_total_balance(state: BeaconState) -> Gwei:
+def get_total_active_balance(state: BeaconState) -> Gwei:
    return get_total_balance(state, get_active_validator_indices(state, get_current_epoch(state)))
 ```

 ```python
-def get_previous_total_balance(state: BeaconState) -> Gwei:
-    return get_total_balance(state, get_active_validator_indices(state, get_previous_epoch(state)))
+def get_matching_source_attestations(state: BeaconState, epoch: Epoch) -> List[PendingAttestation]:
+    assert epoch in (get_current_epoch(state), get_previous_epoch(state))
+    return state.current_epoch_attestations if epoch == get_current_epoch(state) else state.previous_epoch_attestations
+```
+
+```python
+def get_matching_target_attestations(state: BeaconState, epoch: Epoch) -> List[PendingAttestation]:
+    return [
+        a for a in get_matching_source_attestations(state, epoch)
+        if a.data.target_root == get_block_root(state, epoch)
+    ]
+```
+
+```python
+def get_matching_head_attestations(state: BeaconState, epoch: Epoch) -> List[PendingAttestation]:
+    return [
+        a for a in get_matching_source_attestations(state, epoch)
+        if a.data.beacon_block_root == get_block_root_at_slot(state, a.data.slot)
+    ]
 ```

 ```python
@@ -1483,32 +1475,6 @@ def get_attesting_balance(state: BeaconState, attestations: List[PendingAttestat
    return get_total_balance(state, get_unslashed_attesting_indices(state, attestations))
 ```

-```python
-def get_current_epoch_boundary_attestations(state: BeaconState) -> List[PendingAttestation]:
-    return [
-        a for a in state.current_epoch_attestations
-        if a.data.target_root == get_block_root(state, get_epoch_start_slot(get_current_epoch(state)))
-    ]
-```
-
-```python
-def get_previous_epoch_boundary_attestations(state: BeaconState) -> List[PendingAttestation]:
-    return [
-        a for a in state.previous_epoch_attestations
-        if a.data.target_root == get_block_root(state, get_epoch_start_slot(get_previous_epoch(state)))
-    ]
-```
-
-```python
-def get_previous_epoch_matching_head_attestations(state: BeaconState) -> List[PendingAttestation]:
-    return [
-        a for a in state.previous_epoch_attestations
-        if a.data.beacon_block_root == get_block_root(state, a.data.slot)
-    ]
-```
-
-**Note**: Total balances computed for the previous epoch might be marginally different than the actual total balances during the previous epoch transition. Due to the tight bound on validator churn each epoch and small per-epoch rewards/penalties, the potential balance difference is very low and only marginally affects consensus safety.
-
 ```python
 def get_crosslink_from_attestation_data(state: BeaconState, data: AttestationData) -> Crosslink:
    return Crosslink(
@@ -1519,9 +1485,8 @@ def get_crosslink_from_attestation_data(state: BeaconState, data: AttestationDat
 ```

 ```python
-def get_winning_crosslink_and_attesting_indices(state: BeaconState, epoch: Epoch, shard: Shard) -> Tuple[Crosslink, List[ValidatorIndex]]:
-    pending_attestations = state.current_epoch_attestations if epoch == get_current_epoch(state) else state.previous_epoch_attestations
-    shard_attestations = [a for a in pending_attestations if a.data.shard == shard]
+def get_winning_crosslink_and_attesting_indices(state: BeaconState, shard: Shard, epoch: Epoch) -> Tuple[Crosslink, List[ValidatorIndex]]:
+    shard_attestations = [a for a in get_matching_source_attestations(state, epoch) if a.data.shard == shard]
    shard_crosslinks = [get_crosslink_from_attestation_data(state, a.data) for a in shard_attestations]
    candidate_crosslinks = [
        c for c in shard_crosslinks
@@ -1556,6 +1521,8 @@ def process_justification_and_finalization(state: BeaconState) -> None:
    if get_current_epoch(state) <= GENESIS_EPOCH + 1:
        return

+    previous_epoch = get_previous_epoch(state)
+    current_epoch = get_current_epoch(state)
    old_previous_justified_epoch = state.previous_justified_epoch
    old_current_justified_epoch = state.current_justified_epoch

@@ -1563,36 +1530,35 @@ def process_justification_and_finalization(state: BeaconState) -> None:
    state.previous_justified_epoch = state.current_justified_epoch
    state.previous_justified_root = state.current_justified_root
    state.justification_bitfield = (state.justification_bitfield << 1) % 2**64
-    previous_boundary_attesting_balance = get_attesting_balance(state, get_previous_epoch_boundary_attestations(state))
-    if previous_boundary_attesting_balance * 3 >= get_previous_total_balance(state) * 2:
-        state.current_justified_epoch = get_previous_epoch(state)
-        state.current_justified_root = get_block_root(state, get_epoch_start_slot(state.current_justified_epoch))
+    previous_epoch_matching_target_balance = get_attesting_balance(state, get_matching_target_attestations(state, previous_epoch))
+    if previous_epoch_matching_target_balance * 3 >= get_total_active_balance(state) * 2:
+        state.current_justified_epoch = previous_epoch
+        state.current_justified_root = get_block_root(state, state.current_justified_epoch)
        state.justification_bitfield |= (1 << 1)
-    current_boundary_attesting_balance = get_attesting_balance(state, get_current_epoch_boundary_attestations(state))
-    if current_boundary_attesting_balance * 3 >= get_current_total_balance(state) * 2:
-        state.current_justified_epoch = get_current_epoch(state)
-        state.current_justified_root = get_block_root(state, get_epoch_start_slot(state.current_justified_epoch))
+    current_epoch_matching_target_balance = get_attesting_balance(state, get_matching_target_attestations(state, current_epoch))
+    if current_epoch_matching_target_balance * 3 >= get_total_active_balance(state) * 2:
+        state.current_justified_epoch = current_epoch
+        state.current_justified_root = get_block_root(state, state.current_justified_epoch)
        state.justification_bitfield |= (1 << 0)

    # Process finalizations
    bitfield = state.justification_bitfield
-    current_epoch = get_current_epoch(state)
    # The 2nd/3rd/4th most recent epochs are justified, the 2nd using the 4th as source
    if (bitfield >> 1) % 8 == 0b111 and old_previous_justified_epoch == current_epoch - 3:
        state.finalized_epoch = old_previous_justified_epoch
-        state.finalized_root = get_block_root(state, get_epoch_start_slot(state.finalized_epoch))
+        state.finalized_root = get_block_root(state, state.finalized_epoch)
    # The 2nd/3rd most recent epochs are justified, the 2nd using the 3rd as source
    if (bitfield >> 1) % 4 == 0b11 and old_previous_justified_epoch == current_epoch - 2:
        state.finalized_epoch = old_previous_justified_epoch
-        state.finalized_root = get_block_root(state, get_epoch_start_slot(state.finalized_epoch))
+        state.finalized_root = get_block_root(state, state.finalized_epoch)
    # The 1st/2nd/3rd most recent epochs are justified, the 1st using the 3rd as source
    if (bitfield >> 0) % 8 == 0b111 and old_current_justified_epoch == current_epoch - 2:
        state.finalized_epoch = old_current_justified_epoch
-        state.finalized_root = get_block_root(state, get_epoch_start_slot(state.finalized_epoch))
+        state.finalized_root = get_block_root(state, state.finalized_epoch)
    # The 1st/2nd most recent epochs are justified, the 1st using the 2nd as source
    if (bitfield >> 0) % 4 == 0b11 and old_current_justified_epoch == current_epoch - 1:
        state.finalized_epoch = old_current_justified_epoch
-        state.finalized_root = get_block_root(state, get_epoch_start_slot(state.finalized_epoch))
+        state.finalized_root = get_block_root(state, state.finalized_epoch)
 ```

 #### Crosslinks
@@ -1605,8 +1571,9 @@ def process_crosslinks(state: BeaconState) -> None:
    previous_epoch = get_previous_epoch(state)
    next_epoch = get_current_epoch(state) + 1
    for slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_slot(next_epoch)):
+        epoch = slot_to_epoch(slot)
        for crosslink_committee, shard in get_crosslink_committees_at_slot(state, slot):
-            winning_crosslink, attesting_indices = get_winning_crosslink_and_attesting_indices(state, slot_to_epoch(slot), shard)
+            winning_crosslink, attesting_indices = get_winning_crosslink_and_attesting_indices(state, shard, epoch)
            if 3 * get_total_balance(state, attesting_indices) >= 2 * get_total_balance(state, crosslink_committee):
                state.current_crosslinks[shard] = winning_crosslink
 ```
@@ -1615,74 +1582,55 @@ def process_crosslinks(state: BeaconState) -> None:

 First, we define additional helpers:

-```python
-def get_base_reward_from_total_balance(state: BeaconState, total_balance: Gwei, index: ValidatorIndex) -> Gwei:
-    if total_balance == 0:
-        return 0
-
-    adjusted_quotient = integer_squareroot(total_balance) // BASE_REWARD_QUOTIENT
-    return get_effective_balance(state, index) // adjusted_quotient // 5
-```
-
 ```python
 def get_base_reward(state: BeaconState, index: ValidatorIndex) -> Gwei:
-    return get_base_reward_from_total_balance(state, get_previous_total_balance(state), index)
+    adjusted_quotient = integer_squareroot(get_total_active_balance(state)) // BASE_REWARD_QUOTIENT
+    if adjusted_quotient == 0:
+        return 0
+    return state.validator_registry[index].effective_balance // adjusted_quotient // BASE_REWARDS_PER_EPOCH
+
 ```

 ```python
-def get_inactivity_penalty(state: BeaconState, index: ValidatorIndex, epochs_since_finality: int) -> Gwei:
-    if epochs_since_finality <= 4:
-        extra_penalty = 0
-    else:
-        extra_penalty = get_effective_balance(state, index) * epochs_since_finality // INACTIVITY_PENALTY_QUOTIENT // 2
-    return get_base_reward(state, index) + extra_penalty
-```
-
-```python
-def get_justification_and_finalization_deltas(state: BeaconState) -> Tuple[List[Gwei], List[Gwei]]:
-    current_epoch = get_current_epoch(state)
-    epochs_since_finality = current_epoch + 1 - state.finalized_epoch
+def get_attestation_deltas(state: BeaconState) -> Tuple[List[Gwei], List[Gwei]]:
+    previous_epoch = get_previous_epoch(state)
+    total_balance = get_total_active_balance(state)
    rewards = [0 for index in range(len(state.validator_registry))]
    penalties = [0 for index in range(len(state.validator_registry))]
-    # Some helper variables
-    boundary_attestations = get_previous_epoch_boundary_attestations(state)
-    boundary_attesting_balance = get_attesting_balance(state, boundary_attestations)
-    total_balance = get_previous_total_balance(state)
-    total_attesting_balance = get_attesting_balance(state, state.previous_epoch_attestations)
-    matching_head_attestations = get_previous_epoch_matching_head_attestations(state)
-    matching_head_balance = get_attesting_balance(state, matching_head_attestations)
-    eligible_validators = [
-        index for index, validator in enumerate(state.validator_registry)
-        if (
-            is_active_validator(validator, current_epoch) or
-            (validator.slashed and current_epoch < validator.withdrawable_epoch)
-        )
+    eligible_validator_indices = [
+        index for index, v in enumerate(state.validator_registry)
+        if is_active_validator(v, previous_epoch) or (v.slashed and previous_epoch + 1 < v.withdrawable_epoch)
    ]
-    # Process rewards or penalties for all validators
-    for index in eligible_validators:
-        base_reward = get_base_reward(state, index)
-        # Expected FFG source
-        if index in get_unslashed_attesting_indices(state, state.previous_epoch_attestations):
-            rewards[index] += base_reward * total_attesting_balance // total_balance
-            # Inclusion speed bonus
-            earliest_attestation = get_earliest_attestation(state, state.previous_epoch_attestations, index)
-            inclusion_delay = earliest_attestation.inclusion_slot - earliest_attestation.data.slot
-            rewards[index] += base_reward * MIN_ATTESTATION_INCLUSION_DELAY // inclusion_delay
-        else:
-            penalties[index] += base_reward
-        # Expected FFG target
-        if index in get_unslashed_attesting_indices(state, boundary_attestations):
-            rewards[index] += base_reward * boundary_attesting_balance // total_balance
-        else:
-            penalties[index] += get_inactivity_penalty(state, index, epochs_since_finality)
-        # Expected head
-        if index in get_unslashed_attesting_indices(state, matching_head_attestations):
-            rewards[index] += base_reward * matching_head_balance // total_balance
-        else:
-            penalties[index] += base_reward
-        # Take away max rewards if we're not finalizing
-        if epochs_since_finality > 4:
-            penalties[index] += base_reward * 4
+
+    # Micro-incentives for matching FFG source, FFG target, and head
+    matching_source_attestations = get_matching_source_attestations(state, previous_epoch)
+    matching_target_attestations = get_matching_target_attestations(state, previous_epoch)
+    matching_head_attestations = get_matching_head_attestations(state, previous_epoch)
+    for attestations in (matching_source_attestations, matching_target_attestations, matching_head_attestations):
+        unslashed_attesting_indices = get_unslashed_attesting_indices(state, attestations)
+        attesting_balance = get_attesting_balance(state, attestations)
+        for index in eligible_validator_indices:
+            if index in unslashed_attesting_indices:
+                rewards[index] += get_base_reward(state, index) * attesting_balance // total_balance
+            else:
+                penalties[index] += get_base_reward(state, index)
+
+    # Proposer and inclusion delay micro-rewards
+    for index in get_unslashed_attesting_indices(state, matching_source_attestations):
+        earliest_attestation = get_earliest_attestation(state, matching_source_attestations, index)
+        rewards[earliest_attestation.proposer_index] += get_base_reward(state, index) // PROPOSER_REWARD_QUOTIENT
+        inclusion_delay = earliest_attestation.inclusion_slot - earliest_attestation.data.slot
+        rewards[index] += get_base_reward(state, index) * MIN_ATTESTATION_INCLUSION_DELAY // inclusion_delay
+
+    # Inactivity penalty
+    finality_delay = previous_epoch - state.finalized_epoch
+    if finality_delay > MIN_EPOCHS_TO_INACTIVITY_PENALTY:
+        matching_target_attesting_indices = get_unslashed_attesting_indices(state, matching_target_attestations)
+        for index in eligible_validator_indices:
+            penalties[index] += BASE_REWARDS_PER_EPOCH * get_base_reward(state, index)
+            if index not in matching_target_attesting_indices:
+                penalties[index] += state.validator_registry[index].effective_balance * finality_delay // INACTIVITY_PENALTY_QUOTIENT
+
    return [rewards, penalties]
 ```

@@ -1691,15 +1639,17 @@ def get_crosslink_deltas(state: BeaconState) -> Tuple[List[Gwei], List[Gwei]]:
    rewards = [0 for index in range(len(state.validator_registry))]
    penalties = [0 for index in range(len(state.validator_registry))]
    for slot in range(get_epoch_start_slot(get_previous_epoch(state)), get_epoch_start_slot(get_current_epoch(state))):
+        epoch = slot_to_epoch(slot)
        for crosslink_committee, shard in get_crosslink_committees_at_slot(state, slot):
-            winning_crosslink, attesting_indices = get_winning_crosslink_and_attesting_indices(state, slot_to_epoch(slot), shard)
+            winning_crosslink, attesting_indices = get_winning_crosslink_and_attesting_indices(state, shard, epoch)
            attesting_balance = get_total_balance(state, attesting_indices)
            committee_balance = get_total_balance(state, crosslink_committee)
            for index in crosslink_committee:
+                base_reward = get_base_reward(state, index)
                if index in attesting_indices:
-                    rewards[index] += get_base_reward(state, index) * attesting_balance // committee_balance
+                    rewards[index] += base_reward * attesting_balance // committee_balance
                else:
-                    penalties[index] += get_base_reward(state, index)
+                    penalties[index] += base_reward
    return [rewards, penalties]
 ```

@@ -1710,7 +1660,7 @@ def process_rewards_and_penalties(state: BeaconState) -> None:
    if get_current_epoch(state) == GENESIS_EPOCH:
        return

-    rewards1, penalties1 = get_justification_and_finalization_deltas(state)
+    rewards1, penalties1 = get_attestation_deltas(state)
    rewards2, penalties2 = get_crosslink_deltas(state)
    for i in range(len(state.validator_registry)):
        increase_balance(state, i, rewards1[i] + rewards2[i])
@@ -1725,11 +1675,10 @@ Run the following function:
 def process_registry_updates(state: BeaconState) -> None:
    # Process activation eligibility and ejections
    for index, validator in enumerate(state.validator_registry):
-        balance = get_balance(state, index)
-        if validator.activation_eligibility_epoch == FAR_FUTURE_EPOCH and balance >= MAX_EFFECTIVE_BALANCE:
+        if validator.activation_eligibility_epoch == FAR_FUTURE_EPOCH and validator.effective_balance >= MAX_EFFECTIVE_BALANCE:
            validator.activation_eligibility_epoch = get_current_epoch(state)

-        if is_active_validator(validator, get_current_epoch(state)) and balance < EJECTION_BALANCE:
+        if is_active_validator(validator, get_current_epoch(state)) and validator.effective_balance <= EJECTION_BALANCE:
            initiate_validator_exit(state, index)

    # Queue validators eligible for activation and not dequeued for activation prior to finalized epoch
@@ -1762,8 +1711,8 @@ def process_slashings(state: BeaconState) -> None:
    for index, validator in enumerate(state.validator_registry):
        if validator.slashed and current_epoch == validator.withdrawable_epoch - LATEST_SLASHED_EXIT_LENGTH // 2:
            penalty = max(
-                get_effective_balance(state, index) * min(total_penalties * 3, total_balance) // total_balance,
-                get_effective_balance(state, index) // MIN_PENALTY_QUOTIENT
+                validator.effective_balance * min(total_penalties * 3, total_balance) // total_balance,
+                validator.effective_balance // MIN_SLASHING_PENALTY_QUOTIENT
            )
            decrease_balance(state, index, penalty)
 ```
@@ -1779,6 +1728,12 @@ def process_final_updates(state: BeaconState) -> None:
    # Reset eth1 data votes
    if state.slot % SLOTS_PER_ETH1_VOTING_PERIOD == 0:
        state.eth1_data_votes = []
+    # Update effective balances with hysteresis
+    for index, validator in enumerate(state.validator_registry):
+        balance = min(state.balances[index], MAX_EFFECTIVE_BALANCE)
+        HALF_INCREMENT = EFFECTIVE_BALANCE_INCREMENT // 2
+        if balance < validator.effective_balance or validator.effective_balance + 3 * HALF_INCREMENT < balance:
+            validator.effective_balance = balance - balance % EFFECTIVE_BALANCE_INCREMENT
    # Update start shard
    state.latest_start_shard = (state.latest_start_shard + get_shard_delta(state, current_epoch)) % SHARD_COUNT
    # Set active index root
@@ -1962,7 +1917,8 @@ def process_attestation(state: BeaconState, attestation: Attestation) -> None:
    pending_attestation = PendingAttestation(
        data=data,
        aggregation_bitfield=attestation.aggregation_bitfield,
-        inclusion_slot=state.slot
+        inclusion_slot=state.slot,
+        proposer_index=get_beacon_proposer_index(state),
    )
    if target_epoch == get_current_epoch(state):
        state.current_epoch_attestations.append(pending_attestation)
@@ -1970,18 +1926,6 @@ def process_attestation(state: BeaconState, attestation: Attestation) -> None:
        state.previous_epoch_attestations.append(pending_attestation)
 ```

-Run `process_proposer_attestation_rewards(state)`.
-
-```python
-def process_proposer_attestation_rewards(state: BeaconState) -> None:
-    proposer_index = get_beacon_proposer_index(state)
-    for pending_attestations in (state.previous_epoch_attestations, state.current_epoch_attestations):
-        for index in get_unslashed_attesting_indices(state, pending_attestations):
-            if get_earliest_attestation(state, pending_attestations, index).inclusion_slot == state.slot:
-                base_reward = get_base_reward_from_total_balance(state, get_current_total_balance(state), index)
-                increase_balance(state, proposer_index, base_reward // PROPOSER_REWARD_QUOTIENT)
-```
-
 ##### Deposits

 Verify that `len(block.body.deposits) == min(MAX_DEPOSITS, state.latest_eth1_data.deposit_count - state.deposit_index)`.
@@ -1991,54 +1935,41 @@ For each `deposit` in `block.body.deposits`, run the following function:
 ```python
 def process_deposit(state: BeaconState, deposit: Deposit) -> None:
    """
-    Process a deposit from Ethereum 1.0.
-    Used to add a validator or top up an existing validator's
-    balance by some ``deposit`` amount.
-
+    Process an Eth1 deposit, registering a validator or increasing its balance.
    Note that this function mutates ``state``.
    """
-    # Deposits must be processed in order
-    assert deposit.index == state.deposit_index
-
    # Verify the Merkle branch
-    merkle_branch_is_valid = verify_merkle_branch(
+    assert verify_merkle_branch(
        leaf=hash_tree_root(deposit.data),
        proof=deposit.proof,
        depth=DEPOSIT_CONTRACT_TREE_DEPTH,
        index=deposit.index,
        root=state.latest_eth1_data.deposit_root,
    )
-    assert merkle_branch_is_valid

-    # Increment the next deposit index we are expecting. Note that this
-    # needs to be done here because while the deposit contract will never
-    # create an invalid Merkle branch, it may admit an invalid deposit
-    # object, and we need to be able to skip over it
+    # Deposits must be processed in order
+    assert deposit.index == state.deposit_index
    state.deposit_index += 1

-    validator_pubkeys = [v.pubkey for v in state.validator_registry]
    pubkey = deposit.data.pubkey
    amount = deposit.data.amount
-
+    validator_pubkeys = [v.pubkey for v in state.validator_registry]
    if pubkey not in validator_pubkeys:
        # Verify the deposit signature (proof of possession)
        if not bls_verify(pubkey, signing_root(deposit.data), deposit.data.signature, get_domain(state, DOMAIN_DEPOSIT)):
            return

-        # Add new validator
-        validator = Validator(
+        # Add validator and balance entries
+        state.validator_registry.append(Validator(
            pubkey=pubkey,
            withdrawal_credentials=deposit.data.withdrawal_credentials,
            activation_eligibility_epoch=FAR_FUTURE_EPOCH,
            activation_epoch=FAR_FUTURE_EPOCH,
            exit_epoch=FAR_FUTURE_EPOCH,
            withdrawable_epoch=FAR_FUTURE_EPOCH,
-        )
-
-        # Note: In phase 2 registry indices that have been withdrawn for a long time will be recycled.
-        state.validator_registry.append(validator)
-        state.balances.append(0)
-        set_balance(state, len(state.validator_registry) - 1, amount)
+            effective_balance=amount - amount % EFFECTIVE_BALANCE_INCREMENT
+        ))
+        state.balances.append(amount)
    else:
        # Increase balance by deposit amount
        index = validator_pubkeys.index(pubkey)
@@ -2085,15 +2016,15 @@ def process_transfer(state: BeaconState, transfer: Transfer) -> None:
    Process ``Transfer`` operation.
    Note that this function mutates ``state``.
    """
-    # Verify the amount and fee aren't individually too big (for anti-overflow purposes)
-    assert get_balance(state, transfer.sender) >= max(transfer.amount, transfer.fee)
+    # Verify the amount and fee are not individually too big (for anti-overflow purposes)
+    assert state.balances[transfer.sender] >= max(transfer.amount, transfer.fee)
    # A transfer is valid in only one slot
    assert state.slot == transfer.slot
    # Sender must be not yet eligible for activation, withdrawn, or transfer balance over MAX_EFFECTIVE_BALANCE
    assert (
        state.validator_registry[transfer.sender].activation_eligibility_epoch == FAR_FUTURE_EPOCH or
        get_current_epoch(state) >= state.validator_registry[transfer.sender].withdrawable_epoch or
-        transfer.amount + transfer.fee + MAX_EFFECTIVE_BALANCE <= get_balance(state, transfer.sender)
+        transfer.amount + transfer.fee + MAX_EFFECTIVE_BALANCE <= state.balances[transfer.sender]
    )
    # Verify that the pubkey is valid
    assert (
@@ -2107,8 +2038,8 @@ def process_transfer(state: BeaconState, transfer: Transfer) -> None:
    increase_balance(state, transfer.recipient, transfer.amount)
    increase_balance(state, get_beacon_proposer_index(state), transfer.fee)
    # Verify balances are not dust
-    assert not (0 < get_balance(state, transfer.sender) < MIN_DEPOSIT_AMOUNT)
-    assert not (0 < get_balance(state, transfer.recipient) < MIN_DEPOSIT_AMOUNT)
+    assert not (0 < state.balances[transfer.sender] < MIN_DEPOSIT_AMOUNT)
+    assert not (0 < state.balances[transfer.recipient] < MIN_DEPOSIT_AMOUNT)
 ```

 #### State root verification
--- a/specs/light_client/sync_protocol.md
+++ b/specs/light_client/sync_protocol.md
@@ -180,8 +180,8 @@ def verify_block_validity_proof(proof: BlockValidityProof, validator_memory: Val
    assert proof.shard_parent_block.beacon_chain_root == hash_tree_root(proof.header)
    committee = compute_committee(proof.header, validator_memory)
    # Verify that we have >=50% support
-    support_balance = sum([v.high_balance for i, v in enumerate(committee) if get_bitfield_bit(proof.shard_bitfield, i) is True])
-    total_balance = sum([v.high_balance for i, v in enumerate(committee)])
+    support_balance = sum([v.effective_balance for i, v in enumerate(committee) if get_bitfield_bit(proof.shard_bitfield, i) is True])
+    total_balance = sum([v.effective_balance for i, v in enumerate(committee)])
    assert support_balance * 2 > total_balance
    # Verify shard attestations
    group_public_key = bls_aggregate_pubkeys([
--- a/specs/validator/0_beacon-chain-validator.md
+++ b/specs/validator/0_beacon-chain-validator.md
@@ -138,7 +138,7 @@ A validator has two primary responsibilities to the beacon chain -- [proposing b

 ### Block proposal

-A validator is expected to propose a [`BeaconBlock`](../core/0_beacon-chain.md#beaconblock) at the beginning of any slot during which `get_beacon_proposer_index(state, slot)` returns the validator's `validator_index`. To propose, the validator selects the `BeaconBlock`, `parent`, that in their view of the fork choice is the head of the chain during `slot - 1`. The validator is to create, sign, and broadcast a `block` that is a child of `parent` and that executes a valid [beacon chain state transition](../core/0_beacon-chain.md#beacon-chain-state-transition-function).
+A validator is expected to propose a [`BeaconBlock`](../core/0_beacon-chain.md#beaconblock) at the beginning of any slot during which `get_beacon_proposer_index(state)` returns the validator's `validator_index`. To propose, the validator selects the `BeaconBlock`, `parent`, that in their view of the fork choice is the head of the chain during `slot - 1`. The validator is to create, sign, and broadcast a `block` that is a child of `parent` and that executes a valid [beacon chain state transition](../core/0_beacon-chain.md#beacon-chain-state-transition-function).

 There is one proposer per slot, so if there are N active validators any individual validator will on average be assigned to propose once per N slots (e.g. at 312500 validators = 10 million ETH, that's once per ~3 weeks).

@@ -368,7 +368,7 @@ def get_committee_assignment(
            return assignment
 ```

-A validator can use the following function to see if they are supposed to propose during their assigned committee slot. This function can only be run during the slot in question and can not reliably be used to predict in advance.
+A validator can use the following function to see if they are supposed to propose during their assigned committee slot. This function can only be run during the slot in question. Proposer selection is only stable within the context of the current epoch.

 ```python
 def is_proposer_at_slot(state: BeaconState,
--- a/test_libs/pyspec/eth2spec/phase0/state_transition.py
+++ b/test_libs/pyspec/eth2spec/phase0/state_transition.py
@@ -11,7 +11,6 @@ from .spec import (
    BeaconState,
    BeaconBlock,
    Slot,
-    process_proposer_attestation_rewards,
 )


@@ -52,7 +51,6 @@ def process_operations(state: BeaconState, block: BeaconBlock) -> None:
        spec.MAX_ATTESTATIONS,
        spec.process_attestation,
    )
-    process_proposer_attestation_rewards(state)

    assert len(block.body.deposits) == expected_deposit_count(state)
    process_operation_type(
--- a/test_libs/pyspec/tests/block_processing/test_process_attester_slashing.py
+++ b/test_libs/pyspec/tests/block_processing/test_process_attester_slashing.py
@@ -3,11 +3,11 @@ import pytest

 import eth2spec.phase0.spec as spec
 from eth2spec.phase0.spec import (
-    get_balance,
    get_beacon_proposer_index,
    process_attester_slashing,
 )
 from tests.helpers import (
+    get_balance,
    get_valid_attester_slashing,
    next_epoch,
 )
--- a/test_libs/pyspec/tests/block_processing/test_process_deposit.py
+++ b/test_libs/pyspec/tests/block_processing/test_process_deposit.py
@@ -4,11 +4,11 @@ import pytest
 import eth2spec.phase0.spec as spec

 from eth2spec.phase0.spec import (
-    get_balance,
    ZERO_HASH,
    process_deposit,
 )
 from tests.helpers import (
+    get_balance,
    build_deposit,
    privkeys,
    pubkeys,
--- a/test_libs/pyspec/tests/block_processing/test_process_proposer_slashing.py
+++ b/test_libs/pyspec/tests/block_processing/test_process_proposer_slashing.py
@@ -3,11 +3,11 @@ import pytest

 import eth2spec.phase0.spec as spec
 from eth2spec.phase0.spec import (
-    get_balance,
    get_current_epoch,
    process_proposer_slashing,
 )
 from tests.helpers import (
+    get_balance,
    get_valid_proposer_slashing,
 )

--- a/test_libs/pyspec/tests/block_processing/test_process_transfer.py
+++ b/test_libs/pyspec/tests/block_processing/test_process_transfer.py
@@ -5,11 +5,9 @@ import eth2spec.phase0.spec as spec

 from eth2spec.phase0.spec import (
    get_active_validator_indices,
-    get_balance,
    get_beacon_proposer_index,
    get_current_epoch,
    process_transfer,
-    set_balance,
 )
 from tests.helpers import (
    get_valid_transfer,
@@ -75,7 +73,7 @@ def test_success_withdrawable(state):
 def test_success_active_above_max_effective(state):
    sender_index = get_active_validator_indices(state, get_current_epoch(state))[-1]
    amount = spec.MAX_EFFECTIVE_BALANCE // 32
-    set_balance(state, sender_index, spec.MAX_EFFECTIVE_BALANCE + amount)
+    state.balances[sender_index] = spec.MAX_EFFECTIVE_BALANCE + amount
    transfer = get_valid_transfer(state, sender_index=sender_index, amount=amount, fee=0)

    pre_state, post_state = run_transfer_processing(state, transfer)
@@ -86,7 +84,7 @@ def test_success_active_above_max_effective(state):
 def test_active_but_transfer_past_effective_balance(state):
    sender_index = get_active_validator_indices(state, get_current_epoch(state))[-1]
    amount = spec.MAX_EFFECTIVE_BALANCE // 32
-    set_balance(state, sender_index, spec.MAX_EFFECTIVE_BALANCE)
+    state.balances[sender_index] = spec.MAX_EFFECTIVE_BALANCE
    transfer = get_valid_transfer(state, sender_index=sender_index, amount=amount, fee=0)

    pre_state, post_state = run_transfer_processing(state, transfer, False)
@@ -107,7 +105,7 @@ def test_incorrect_slot(state):
 def test_insufficient_balance(state):
    sender_index = get_active_validator_indices(state, get_current_epoch(state))[-1]
    amount = spec.MAX_EFFECTIVE_BALANCE
-    set_balance(state, sender_index, spec.MAX_EFFECTIVE_BALANCE)
+    state.balances[sender_index] = spec.MAX_EFFECTIVE_BALANCE
    transfer = get_valid_transfer(state, sender_index=sender_index, amount=amount + 1, fee=0)

    # un-activate so validator can transfer
@@ -140,4 +138,4 @@ def test_invalid_pubkey(state):

    pre_state, post_state = run_transfer_processing(state, transfer, False)

-    return pre_state, transfer, post_state
+    return pre_state, transfer, post_state
--- a/test_libs/pyspec/tests/helpers.py
+++ b/test_libs/pyspec/tests/helpers.py
@@ -26,9 +26,9 @@ from eth2spec.phase0.spec import (
    # functions
    convert_to_indexed,
    get_active_validator_indices,
-    get_balance,
    get_attesting_indices,
    get_block_root,
+    get_block_root_at_slot,
    get_crosslink_committees_at_slot,
    get_current_epoch,
    get_domain,
@@ -53,6 +53,10 @@ pubkeys = [bls.privtopub(privkey) for privkey in privkeys]
 pubkey_to_privkey = {pubkey: privkey for privkey, pubkey in zip(privkeys, pubkeys)}


+def get_balance(state, index):
+    return state.balances[index]
+
+
 def set_bitfield_bit(bitfield, i):
    """
    Set the bit in ``bitfield`` at position ``i`` to ``1``.
@@ -150,16 +154,16 @@ def build_attestation_data(state, slot, shard):
    if slot == state.slot:
        block_root = build_empty_block_for_next_slot(state).previous_block_root
    else:
-        block_root = get_block_root(state, slot)
+        block_root = get_block_root_at_slot(state, slot)

    current_epoch_start_slot = get_epoch_start_slot(get_current_epoch(state))
    if slot < current_epoch_start_slot:
        print(slot)
-        epoch_boundary_root = get_block_root(state, get_epoch_start_slot(get_previous_epoch(state)))
+        epoch_boundary_root = get_block_root(state, get_previous_epoch(state))
    elif slot == current_epoch_start_slot:
        epoch_boundary_root = block_root
    else:
-        epoch_boundary_root = get_block_root(state, current_epoch_start_slot)
+        epoch_boundary_root = get_block_root(state, get_current_epoch(state))

    if slot < current_epoch_start_slot:
        justified_epoch = state.previous_justified_epoch
--- a/test_libs/pyspec/tests/test_sanity.py
+++ b/test_libs/pyspec/tests/test_sanity.py
@@ -15,16 +15,13 @@ from eth2spec.phase0.spec import (
    VoluntaryExit,
    # functions
    get_active_validator_indices,
-    get_balance,
    get_beacon_proposer_index,
-    get_block_root,
+    get_block_root_at_slot,
+    get_state_root,
    get_current_epoch,
    get_domain,
-    get_state_root,
    advance_slot,
    cache_state,
-    set_balance,
-    slot_to_epoch,
    verify_merkle_branch,
    hash,
 )
@@ -37,6 +34,7 @@ from eth2spec.utils.merkle_minimal import (
    get_merkle_root,
 )
 from .helpers import (
+    get_balance,
    build_deposit_data,
    build_empty_block_for_next_slot,
    fill_aggregate_attestation,
@@ -52,7 +50,6 @@ from .helpers import (
 # mark entire file as 'sanity'
 pytestmark = pytest.mark.sanity

-
 def check_finality(state,
                   prev_state,
                   current_justified_changed,
@@ -96,7 +93,7 @@ def test_empty_block_transition(state):
    state_transition(test_state, block)

    assert len(test_state.eth1_data_votes) == len(state.eth1_data_votes) + 1
-    assert get_block_root(test_state, state.slot) == block.previous_block_root
+    assert get_block_root_at_slot(test_state, state.slot) == block.previous_block_root

    return state, [block], test_state

@@ -110,7 +107,7 @@ def test_skipped_slots(state):

    assert test_state.slot == block.slot
    for slot in range(state.slot, test_state.slot):
-        assert get_block_root(test_state, slot) == block.previous_block_root
+        assert get_block_root_at_slot(test_state, slot) == block.previous_block_root

    return state, [block], test_state

@@ -124,7 +121,7 @@ def test_empty_epoch_transition(state):

    assert test_state.slot == block.slot
    for slot in range(state.slot, test_state.slot):
-        assert get_block_root(test_state, slot) == block.previous_block_root
+        assert get_block_root_at_slot(test_state, slot) == block.previous_block_root

    return state, [block], test_state

@@ -303,6 +300,7 @@ def test_deposit_top_up(state):


 def test_attestation(state):
+    state.slot = spec.SLOTS_PER_EPOCH
    test_state = deepcopy(state)
    attestation = get_valid_attestation(state)

@@ -316,8 +314,6 @@ def test_attestation(state):

    assert len(test_state.current_epoch_attestations) == len(state.current_epoch_attestations) + 1

-    proposer_index = get_beacon_proposer_index(test_state)
-    assert test_state.balances[proposer_index] > state.balances[proposer_index]

    #
    # Epoch transition should move to previous_epoch_attestations
@@ -441,7 +437,7 @@ def test_balance_driven_status_transitions(state):
    assert pre_state.validator_registry[validator_index].exit_epoch == spec.FAR_FUTURE_EPOCH

    # set validator balance to below ejection threshold
-    set_balance(pre_state, validator_index, spec.EJECTION_BALANCE - 1)
+    pre_state.validator_registry[validator_index].effective_balance = spec.EJECTION_BALANCE

    post_state = deepcopy(pre_state)
    #
--- a/tests/phase0/helpers.py
+++ b/tests/phase0/helpers.py
@@ -16,6 +16,7 @@ from build.phase0.spec import (
    VoluntaryExit,
    # functions
    get_block_root,
+    get_block_root_at_slot,
    get_current_epoch,
    get_domain,
    get_empty_block,
@@ -141,7 +142,7 @@ def build_attestation_data(state, slot, shard):
    if epoch_start_slot == slot:
        epoch_boundary_root = block_root
    else:
-        get_block_root(state, epoch_start_slot)
+        epoch_boundary_root = get_block_root(state, get_current_epoch(state))

    if slot < epoch_start_slot:
        justified_block_root = state.previous_justified_root