Merge pull request #2198 from ethereum/hf1-config

update penalty config values for hf1

configs/mainnet/lightclient_patch.yaml

@@ -2,6 +2,16 @@
 
 CONFIG_NAME: "mainnet"
 
+# Updated penalty values
+# ---------------------------------------------------------------
+# 3 * 2**24) (= 50,331,648)
+HF1_INACTIVITY_PENALTY_QUOTIENT: 50331648
+# 2**6 (= 64)
+HF1_MIN_SLASHING_PENALTY_QUOTIENT: 64
+# 2
+HF1_PROPORTIONAL_SLASHING_MULTIPLIER: 2
+
+
 # Misc
 # ---------------------------------------------------------------
 # 2**10 (=1,024)

configs/minimal/lightclient_patch.yaml

@@ -2,6 +2,16 @@
 
 CONFIG_NAME: "minimal"
 
+# Updated penalty values
+# ---------------------------------------------------------------
+# 3 * 2**24) (= 50,331,648)
+HF1_INACTIVITY_PENALTY_QUOTIENT: 50331648
+# 2**6 (= 64)
+HF1_MIN_SLASHING_PENALTY_QUOTIENT: 64
+# 2
+HF1_PROPORTIONAL_SLASHING_MULTIPLIER: 2
+
+
 # Misc
 # ---------------------------------------------------------------
 # [customized]

specs/lightclient/beacon-chain.md

@@ -13,6 +13,7 @@
   - [Participation rewards](#participation-rewards)
   - [Misc](#misc)
 - [Configuration](#configuration)
+  - [Updated penalty values](#updated-penalty-values)
   - [Misc](#misc-1)
   - [Time parameters](#time-parameters)
   - [Domain types](#domain-types)
@@ -34,6 +35,8 @@
     - [`get_unslashed_participating_indices`](#get_unslashed_participating_indices)
     - [`get_flag_deltas`](#get_flag_deltas)
     - [New `get_inactivity_penalty_deltas`](#new-get_inactivity_penalty_deltas)
+  - [Beacon state mutators](#beacon-state-mutators)
+    - [New `slash_validator`](#new-slash_validator)
   - [Block processing](#block-processing)
     - [New `process_attestation`](#new-process_attestation)
     - [New `process_deposit`](#new-process_deposit)
@@ -41,6 +44,7 @@
   - [Epoch processing](#epoch-processing)
     - [New `process_justification_and_finalization`](#new-process_justification_and_finalization)
     - [New `process_rewards_and_penalties`](#new-process_rewards_and_penalties)
+    - [New `process_slashings`](#new-process_slashings)
     - [Sync committee updates](#sync-committee-updates)
     - [Participation flags updates](#participation-flags-updates)
 
@@ -49,11 +53,13 @@
 
 ## Introduction
 
-This is a patch implementing the first hard fork to the beacon chain, tentatively named HF1 pending a permanent name. It has three main features:
+This is a patch implementing the first hard fork to the beacon chain, tentatively named HF1 pending a permanent name.
+It has four main features:
 
 * Light client support via sync committees
 * Incentive accounting reforms, reducing spec complexity
   and [TODO] reducing the cost of processing chains that have very little or zero participation for a long span of epochs
+* Update penalty configuration values, moving them toward their planned maximally punitive configuration
 * Fork choice rule changes to address weaknesses recently discovered in the existing fork choice
 
 ## Custom types
@@ -97,6 +103,18 @@ The reward fractions add up to 7/8, leaving the remaining 1/8 for proposer rewar
 
 ## Configuration
 
+### Updated penalty values
+
+This patch updates a few configuration values to move penalty constants toward their final, maxmium security values.
+
+*Note*: The spec does *not* override previous configuration values but instead creates new values and replaces usage throughout.
+
+| Name | Value |
+| - | - |
+| `HF1_INACTIVITY_PENALTY_QUOTIENT` | `uint64(3 * 2**24)` (= 50,331,648) |
+| `HF1_MIN_SLASHING_PENALTY_QUOTIENT` | `uint64(2**6)` (=64) |
+| `HF1_PROPORTIONAL_SLASHING_MULTIPLIER` | `uint64(2)` |
+
 ### Misc
 
 | Name | Value |
@@ -328,7 +346,8 @@ def get_flag_deltas(state: BeaconState,
 
 #### New `get_inactivity_penalty_deltas`
 
-*Note*: The function `get_inactivity_penalty_deltas` is modified in the selection of matching target indices and the removal of `BASE_REWARDS_PER_EPOCH`.
+*Note*: The function `get_inactivity_penalty_deltas` is modified in the selection of matching target indices
+and the removal of `BASE_REWARDS_PER_EPOCH`.
 
 ```python
 def get_inactivity_penalty_deltas(state: BeaconState) -> Tuple[Sequence[Gwei], Sequence[Gwei]]:
@@ -348,12 +367,47 @@ def get_inactivity_penalty_deltas(state: BeaconState) -> Tuple[Sequence[Gwei], S
             penalties[index] += Gwei(get_base_reward(state, index) * reward_numerator_sum // REWARD_DENOMINATOR)
             if index not in matching_target_attesting_indices: 
                 effective_balance = state.validators[index].effective_balance
-                penalties[index] += Gwei(effective_balance * get_finality_delay(state) // INACTIVITY_PENALTY_QUOTIENT)
+                penalties[index] += Gwei(
+                    effective_balance * get_finality_delay(state)
+                    // HF1_INACTIVITY_PENALTY_QUOTIENT
+                )
 
     rewards = [Gwei(0) for _ in range(len(state.validators))]
     return rewards, penalties
 ```
 
+### Beacon state mutators
+
+#### New `slash_validator`
+
+*Note*: The function `slash_validator` is modified
+with the substitution of `MIN_SLASHING_PENALTY_QUOTIENT` with `HF1_MIN_SLASHING_PENALTY_QUOTIENT`.
+
+```python
+def slash_validator(state: BeaconState,
+                    slashed_index: ValidatorIndex,
+                    whistleblower_index: ValidatorIndex=None) -> None:
+    """
+    Slash the validator with index ``slashed_index``.
+    """
+    epoch = get_current_epoch(state)
+    initiate_validator_exit(state, slashed_index)
+    validator = state.validators[slashed_index]
+    validator.slashed = True
+    validator.withdrawable_epoch = max(validator.withdrawable_epoch, Epoch(epoch + EPOCHS_PER_SLASHINGS_VECTOR))
+    state.slashings[epoch % EPOCHS_PER_SLASHINGS_VECTOR] += validator.effective_balance
+    decrease_balance(state, slashed_index, validator.effective_balance // HF1_MIN_SLASHING_PENALTY_QUOTIENT)
+
+    # Apply proposer and whistleblower rewards
+    proposer_index = get_beacon_proposer_index(state)
+    if whistleblower_index is None:
+        whistleblower_index = proposer_index
+    whistleblower_reward = Gwei(validator.effective_balance // WHISTLEBLOWER_REWARD_QUOTIENT)
+    proposer_reward = Gwei(whistleblower_reward // PROPOSER_REWARD_QUOTIENT)
+    increase_balance(state, proposer_index, proposer_reward)
+    increase_balance(state, whistleblower_index, Gwei(whistleblower_reward - proposer_reward))
+```
+
 ### Block processing
 
 ```python
@@ -576,6 +630,24 @@ def process_rewards_and_penalties(state: BeaconState) -> None:
             decrease_balance(state, ValidatorIndex(index), penalties[index])
 ```
 
+#### New `process_slashings`
+
+*Note*: The function `process_slashings` is modified
+with the substitution of `PROPORTIONAL_SLASHING_MULTIPLIER` with `HF1_PROPORTIONAL_SLASHING_MULTIPLIER`.
+
+```python
+def process_slashings(state: BeaconState) -> None:
+    epoch = get_current_epoch(state)
+    total_balance = get_total_active_balance(state)
+    adjusted_total_slashing_balance = min(sum(state.slashings) * HF1_PROPORTIONAL_SLASHING_MULTIPLIER, total_balance)
+    for index, validator in enumerate(state.validators):
+        if validator.slashed and epoch + EPOCHS_PER_SLASHINGS_VECTOR // 2 == validator.withdrawable_epoch:
+            increment = EFFECTIVE_BALANCE_INCREMENT  # Factored out from penalty numerator to avoid uint64 overflow
+            penalty_numerator = validator.effective_balance // increment * adjusted_total_slashing_balance
+            penalty = penalty_numerator // total_balance * increment
+            decrease_balance(state, ValidatorIndex(index), penalty)
+```
+
 #### Sync committee updates
 
 ```python

tests/core/pyspec/eth2spec/test/helpers/proposer_slashings.py

@@ -1,8 +1,16 @@
+from eth2spec.test.context import is_post_lightclient_patch
 from eth2spec.test.helpers.block_header import sign_block_header
 from eth2spec.test.helpers.keys import pubkey_to_privkey
 from eth2spec.test.helpers.state import get_balance
 
 
+def get_min_slashing_penalty_quotient(spec):
+    if is_post_lightclient_patch(spec):
+        return spec.HF1_MIN_SLASHING_PENALTY_QUOTIENT
+    else:
+        return spec.MIN_SLASHING_PENALTY_QUOTIENT
+
+
 def check_proposer_slashing_effect(spec, pre_state, state, slashed_index):
     slashed_validator = state.validators[slashed_index]
     assert slashed_validator.slashed
@@ -10,7 +18,7 @@ def check_proposer_slashing_effect(spec, pre_state, state, slashed_index):
     assert slashed_validator.withdrawable_epoch < spec.FAR_FUTURE_EPOCH
 
     proposer_index = spec.get_beacon_proposer_index(state)
-    slash_penalty = state.validators[slashed_index].effective_balance // spec.MIN_SLASHING_PENALTY_QUOTIENT
+    slash_penalty = state.validators[slashed_index].effective_balance // get_min_slashing_penalty_quotient(spec)
     whistleblower_reward = state.validators[slashed_index].effective_balance // spec.WHISTLEBLOWER_REWARD_QUOTIENT
     if proposer_index != slashed_index:
         # slashed validator lost initial slash penalty

tests/core/pyspec/eth2spec/test/phase0/block_processing/test_process_attester_slashing.py

@@ -4,6 +4,7 @@ from eth2spec.test.context import (
 from eth2spec.test.helpers.attestations import sign_indexed_attestation
 from eth2spec.test.helpers.attester_slashings import get_valid_attester_slashing, \
     get_indexed_attestation_participants, get_attestation_2_data, get_attestation_1_data
+from eth2spec.test.helpers.proposer_slashings import get_min_slashing_penalty_quotient
 from eth2spec.test.helpers.state import (
     get_balance,
     next_epoch_via_block,
@@ -70,7 +71,7 @@ def run_attester_slashing_processing(spec, state, attester_slashing, valid=True)
         expected_balance = (
             pre_proposer_balance
             + total_proposer_rewards
-            - pre_slashings[proposer_index] // spec.MIN_SLASHING_PENALTY_QUOTIENT
+            - pre_slashings[proposer_index] // get_min_slashing_penalty_quotient(spec)
         )
 
         assert get_balance(state, proposer_index) == expected_balance

tests/core/pyspec/eth2spec/test/phase0/epoch_processing/test_process_slashings.py

@@ -1,4 +1,4 @@
-from eth2spec.test.context import spec_state_test, with_all_phases
+from eth2spec.test.context import spec_state_test, with_all_phases, is_post_lightclient_patch
 from eth2spec.test.helpers.epoch_processing import (
     run_epoch_processing_with, run_epoch_processing_to
 )
@@ -23,12 +23,19 @@ def slash_validators(spec, state, indices, out_epochs):
     ] = total_slashed_balance
 
 
+def get_slashing_multiplier(spec):
+    if is_post_lightclient_patch(spec):
+        return spec.HF1_PROPORTIONAL_SLASHING_MULTIPLIER
+    else:
+        return spec.PROPORTIONAL_SLASHING_MULTIPLIER
+
+
 @with_all_phases
 @spec_state_test
 def test_max_penalties(spec, state):
     # Slashed count to ensure that enough validators are slashed to induce maximum penalties
     slashed_count = min(
-        (len(state.validators) // spec.PROPORTIONAL_SLASHING_MULTIPLIER) + 1,
+        (len(state.validators) // get_slashing_multiplier(spec)) + 1,
         # Can't slash more than validator count!
         len(state.validators)
     )
@@ -40,7 +47,7 @@ def test_max_penalties(spec, state):
     total_balance = spec.get_total_active_balance(state)
     total_penalties = sum(state.slashings)
 
-    assert total_balance // spec.PROPORTIONAL_SLASHING_MULTIPLIER <= total_penalties
+    assert total_balance // get_slashing_multiplier(spec) <= total_penalties
 
     yield from run_process_slashings(spec, state)
 
@@ -50,7 +57,30 @@ def test_max_penalties(spec, state):
 
 @with_all_phases
 @spec_state_test
-def test_small_penalty(spec, state):
+def test_low_penalty(spec, state):
+    # Slashed count is one tenth of validator set
+    slashed_count = (len(state.validators) // 10) + 1
+    out_epoch = spec.get_current_epoch(state) + (spec.EPOCHS_PER_SLASHINGS_VECTOR // 2)
+
+    slashed_indices = list(range(slashed_count))
+    slash_validators(spec, state, slashed_indices, [out_epoch] * slashed_count)
+
+    pre_state = state.copy()
+
+    yield from run_process_slashings(spec, state)
+
+    for i in slashed_indices:
+        assert 0 < state.balances[i] < pre_state.balances[i]
+
+
+@with_all_phases
+@spec_state_test
+def test_minimal_penalty(spec, state):
+    #
+    # When very few slashings, the resulting slashing penalty gets rounded down
+    # to zero so the result of `process_slashings` is null
+    #
+
     # Just the bare minimum for this one validator
     state.balances[0] = state.validators[0].effective_balance = spec.EJECTION_BALANCE
     # All the other validators get the maximum.
@@ -74,11 +104,13 @@ def test_small_penalty(spec, state):
 
     expected_penalty = (
         state.validators[0].effective_balance // spec.EFFECTIVE_BALANCE_INCREMENT
-        * (3 * total_penalties)
+        * (get_slashing_multiplier(spec) * total_penalties)
         // total_balance
         * spec.EFFECTIVE_BALANCE_INCREMENT
     )
-    assert state.balances[0] == pre_slash_balances[0] - expected_penalty
+
+    assert expected_penalty == 0
+    assert state.balances[0] == pre_slash_balances[0]
 
 
 @with_all_phases
@@ -96,7 +128,7 @@ def test_scaled_penalties(spec, state):
     state.slashings[5] = base + (incr * 6)
     state.slashings[spec.EPOCHS_PER_SLASHINGS_VECTOR - 1] = base + (incr * 7)
 
-    slashed_count = len(state.validators) // (spec.PROPORTIONAL_SLASHING_MULTIPLIER + 1)
+    slashed_count = len(state.validators) // (get_slashing_multiplier(spec) + 1)
 
     assert slashed_count > 10
 
@@ -134,7 +166,7 @@ def test_scaled_penalties(spec, state):
         v = state.validators[i]
         expected_penalty = (
             v.effective_balance // spec.EFFECTIVE_BALANCE_INCREMENT
-            * (spec.PROPORTIONAL_SLASHING_MULTIPLIER * total_penalties)
+            * (get_slashing_multiplier(spec) * total_penalties)
             // (total_balance)
             * spec.EFFECTIVE_BALANCE_INCREMENT
         )