Add seed domains

configs/mainnet.yaml

@@ -60,7 +60,7 @@ SLOTS_PER_EPOCH: 64
 # 2**0 (= 1) epochs 6.4 minutes
 MIN_SEED_LOOKAHEAD: 1
 # 2**2 (= 4) epochs 25.6 minutes
-ACTIVATION_EXIT_DELAY: 4
+MAX_SEED_LOOKAHEAD: 4
 # 2**10 (= 1,024) slots ~1.7 hours
 SLOTS_PER_ETH1_VOTING_PERIOD: 1024
 # 2**13 (= 8,192) slots ~13 hours
@@ -123,8 +123,8 @@ MAX_TRANSFERS: 0
 # Signature domains
 # ---------------------------------------------------------------
 DOMAIN_BEACON_PROPOSER: 0x00000000
-DOMAIN_RANDAO: 0x01000000
-DOMAIN_ATTESTATION: 0x02000000
+DOMAIN_BEACON_ATTESTER: 0x01000000
+DOMAIN_RANDAO: 0x02000000
 DOMAIN_DEPOSIT: 0x03000000
 DOMAIN_VOLUNTARY_EXIT: 0x04000000
 DOMAIN_TRANSFER: 0x05000000

configs/minimal.yaml

@@ -59,7 +59,7 @@ SLOTS_PER_EPOCH: 8
 # 2**0 (= 1) epochs
 MIN_SEED_LOOKAHEAD: 1
 # 2**2 (= 4) epochs
-ACTIVATION_EXIT_DELAY: 4
+MAX_SEED_LOOKAHEAD: 4
 # [customized] higher frequency new deposits from eth1 for testing
 SLOTS_PER_ETH1_VOTING_PERIOD: 16
 # [customized] smaller state
@@ -125,8 +125,8 @@ MAX_TRANSFERS: 0
 # Signature domains
 # ---------------------------------------------------------------
 DOMAIN_BEACON_PROPOSER: 0x00000000
-DOMAIN_RANDAO: 0x01000000
-DOMAIN_ATTESTATION: 0x02000000
+DOMAIN_BEACON_ATTESTER: 0x01000000
+DOMAIN_RANDAO: 0x02000000
 DOMAIN_DEPOSIT: 0x03000000
 DOMAIN_VOLUNTARY_EXIT: 0x04000000
 DOMAIN_TRANSFER: 0x05000000

specs/core/0_beacon-chain.md

@@ -19,7 +19,7 @@
         - [State list lengths](#state-list-lengths)
         - [Rewards and penalties](#rewards-and-penalties)
         - [Max operations per block](#max-operations-per-block)
-        - [Signature domain types](#signature-domain-types)
+        - [Domain types](#domain-types)
     - [Containers](#containers)
         - [Misc dependencies](#misc-dependencies)
             - [`Fork`](#fork)
@@ -148,7 +148,7 @@ We define the following Python custom types for type hinting and readability:
 | `Gwei` | `uint64` | an amount in Gwei |
 | `Hash` | `Bytes32` | a hash |
 | `Version` | `Bytes4` | a fork version number |
-| `DomainType` | `Bytes4` | a signature domain type |
+| `DomainType` | `Bytes4` | a domain type |
 | `Domain` | `Bytes8` | a signature domain |
 | `BLSPubkey` | `Bytes48` | a BLS12-381 public key |
 | `BLSSignature` | `Bytes96` | a BLS12-381 signature |
@@ -210,7 +210,7 @@ The following values are (non-configurable) constants used throughout the specif
 | `MIN_ATTESTATION_INCLUSION_DELAY` | `2**0` (= 1) | slots | 6 seconds |
 | `SLOTS_PER_EPOCH` | `2**6` (= 64) | slots | 6.4 minutes |
 | `MIN_SEED_LOOKAHEAD` | `2**0` (= 1) | epochs | 6.4 minutes |
-| `ACTIVATION_EXIT_DELAY` | `2**2` (= 4) | epochs | 25.6 minutes |
+| `MAX_SEED_LOOKAHEAD` | `2**2` (= 4) | epochs | 25.6 minutes |
 | `SLOTS_PER_ETH1_VOTING_PERIOD` | `2**10` (= 1,024) | slots | ~1.7 hours |
 | `SLOTS_PER_HISTORICAL_ROOT` | `2**13` (= 8,192) | slots | ~13 hours |
 | `MIN_VALIDATOR_WITHDRAWABILITY_DELAY` | `2**8` (= 256) | epochs | ~27 hours |
@@ -250,15 +250,15 @@ The following values are (non-configurable) constants used throughout the specif
 | `MAX_VOLUNTARY_EXITS` | `2**4` (= 16) |
 | `MAX_TRANSFERS` | `0` |
 
-### Signature domain types
+### Domain types
 
 The following types are defined, mapping into `DomainType` (little endian):
 
 | Name | Value |
 | - | - |
 | `DOMAIN_BEACON_PROPOSER` | `0` |
-| `DOMAIN_RANDAO` | `1` |
-| `DOMAIN_ATTESTATION` | `2` |
+| `DOMAIN_BEACON_ATTESTER` | `1` |
+| `DOMAIN_RANDAO` | `2` |
 | `DOMAIN_DEPOSIT` | `3` |
 | `DOMAIN_VOLUNTARY_EXIT` | `4` |
 | `DOMAIN_TRANSFER` | `5` |
@@ -671,7 +671,7 @@ def is_valid_indexed_attestation(state: BeaconState, indexed_attestation: Indexe
             hash_tree_root(AttestationDataAndCustodyBit(data=indexed_attestation.data, custody_bit=0b1)),
         ],
         signature=indexed_attestation.signature,
-        domain=get_domain(state, DOMAIN_ATTESTATION, indexed_attestation.data.target.epoch),
+        domain=get_domain(state, DOMAIN_BEACON_ATTESTER, indexed_attestation.data.target.epoch),
     ):
         return False
     return True
@@ -779,7 +779,7 @@ def compute_activation_exit_epoch(epoch: Epoch) -> Epoch:
     """
     Return the epoch during which validator activations and exits initiated in ``epoch`` take effect.
     """
-    return Epoch(epoch + 1 + ACTIVATION_EXIT_DELAY)
+    return Epoch(epoch + 1 + MAX_SEED_LOOKAHEAD)
 ```
 
 #### `compute_domain`
@@ -870,12 +870,12 @@ def get_validator_churn_limit(state: BeaconState) -> uint64:
 #### `get_seed`
 
 ```python
-def get_seed(state: BeaconState, epoch: Epoch) -> Hash:
+def get_seed(state: BeaconState, epoch: Epoch, domain_type: DomainType) -> Hash:
     """
     Return the seed at ``epoch``.
     """
     mix = get_randao_mix(state, Epoch(epoch + EPOCHS_PER_HISTORICAL_VECTOR - MIN_SEED_LOOKAHEAD - 1))  # Avoid underflow
-    return hash(mix + int_to_bytes(epoch, length=32))
+    return hash(domain_type + int_to_bytes(epoch, length=8) + mix)
 ```
 
 #### `get_committee_count`
@@ -901,7 +901,7 @@ def get_crosslink_committee(state: BeaconState, epoch: Epoch, shard: Shard) -> S
     """
     return compute_committee(
         indices=get_active_validator_indices(state, epoch),
-        seed=get_seed(state, epoch),
+        seed=get_seed(state, epoch, DOMAIN_BEACON_ATTESTER),
         index=(shard + SHARD_COUNT - get_start_shard(state, epoch)) % SHARD_COUNT,
         count=get_committee_count(state, epoch),
     )
@@ -941,7 +941,7 @@ def get_beacon_proposer_index(state: BeaconState) -> ValidatorIndex:
     Return the beacon proposer index at the current slot.
     """
     epoch = get_current_epoch(state)
-    seed = hash(get_seed(state, epoch) + int_to_bytes(state.slot, length=8))
+    seed = hash(get_seed(state, epoch, DOMAIN_BEACON_PROPOSER) + int_to_bytes(state.slot, length=8))
     indices = get_active_validator_indices(state, epoch)
     return compute_proposer_index(state, indices, seed)
 ```

specs/core/1_custody-game.md

@@ -282,7 +282,7 @@ def ceillog2(x: uint64) -> int:
 ### `is_valid_merkle_branch_with_mixin`
 
 ```python
-def is_valid_merkle_branch_with_mixin(leaf: Hash, 
+def is_valid_merkle_branch_with_mixin(leaf: Hash,
                                       branch: Sequence[Hash],
                                       depth: uint64,
                                       index: uint64,
@@ -315,7 +315,7 @@ def legendre_bit(a: int, q: int) -> int:
     if a >= q:
         return legendre_bit(a % q, q)
     if a == 0:
-        return 0 
+        return 0
     assert(q > a > 0 and q % 2 == 1)
     t = 1
     n = q
@@ -602,7 +602,7 @@ def process_bit_challenge(state: BeaconState, challenge: CustodyBitChallenge) ->
     # Verify attestation is eligible for challenging
     responder = state.validators[challenge.responder_index]
     assert get_current_epoch(state) <= get_randao_epoch_for_custody_period(
-        get_custody_period_for_validator(state, challenge.responder_index, epoch), 
+        get_custody_period_for_validator(state, challenge.responder_index, epoch),
         challenge.responder_index
     ) + 2 * EPOCHS_PER_CUSTODY_PERIOD + responder.max_reveal_lateness
 
@@ -673,7 +673,7 @@ def process_chunk_challenge_response(state: BeaconState,
     # Verify bit challenge data is null
     assert response.chunk_bits_branch == [] and response.chunk_bits_leaf == Hash()
     # Verify minimum delay
-    assert get_current_epoch(state) >= challenge.inclusion_epoch + ACTIVATION_EXIT_DELAY
+    assert get_current_epoch(state) >= challenge.inclusion_epoch + MAX_SEED_LOOKAHEAD
     # Verify the chunk matches the crosslink data root
     assert is_valid_merkle_branch(
         leaf=hash_tree_root(response.chunk),

specs/core/1_shard-data-chains.md

@@ -225,7 +225,7 @@ def get_period_committee(state: BeaconState, epoch: Epoch, shard: Shard) -> Sequ
     """
     full_committee = compute_committee(
         indices=get_active_validator_indices(state, epoch),
-        seed=get_seed(state, epoch),
+        seed=get_seed(state, epoch, DOMAIN_SHARD_ATTESTER),
         index=shard,
         count=SHARD_COUNT,
     )
@@ -270,7 +270,8 @@ def get_shard_block_proposer_index(state: BeaconState,
         return None
 
     MAX_RANDOM_BYTE = 2**8 - 1
-    seed = hash(get_seed(state, current_epoch) + int_to_bytes(shard, length=8) + int_to_bytes(slot, length=8))
+    epoch_seed = get_seed(state, current_epoch, DOMAIN_SHARD_PROPOSER)
+    seed = hash(epoch_seed + int_to_bytes(shard, length=8) + int_to_bytes(slot, length=8))
     i = 0
     while True:
         candidate_index = active_indices[(slot + i) % len(active_indices)]

specs/validator/0_beacon-chain-validator.md

@@ -114,7 +114,7 @@ Once a validator has been processed and added to the beacon state's `validators`
 
 ### Activation
 
-In normal operation, the validator is quickly activated, at which point the validator is added to the shuffling and begins validation after an additional `ACTIVATION_EXIT_DELAY` epochs (25.6 minutes).
+In normal operation, the validator is quickly activated, at which point the validator is added to the shuffling and begins validation after an additional `MAX_SEED_LOOKAHEAD` epochs (25.6 minutes).
 
 The function [`is_active_validator`](../core/0_beacon-chain.md#is_active_validator) can be used to check if a validator is active during a given epoch. Usage is as follows:
 
@@ -345,7 +345,7 @@ def get_signed_attestation_data(state: BeaconState, attestation: IndexedAttestat
         custody_bit=0b0,
     )
 
-    domain = get_domain(state, DOMAIN_ATTESTATION, attestation.data.target.epoch)
+    domain = get_domain(state, DOMAIN_BEACON_ATTESTER, attestation.data.target.epoch)
     return bls_sign(privkey, hash_tree_root(attestation_data_and_custody_bit), domain)
 ```
 

test_libs/pyspec/eth2spec/test/helpers/attestations.py

@@ -122,7 +122,7 @@ def get_attestation_signature(spec, state, attestation_data, privkey, custody_bi
         privkey=privkey,
         domain=spec.get_domain(
             state=state,
-            domain_type=spec.DOMAIN_ATTESTATION,
+            domain_type=spec.DOMAIN_BEACON_ATTESTER,
             message_epoch=attestation_data.target.epoch,
         )
     )

test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_registry_updates.py

@@ -21,7 +21,7 @@ def test_activation(spec, state):
     index = 0
     mock_deposit(spec, state, index)
 
-    for _ in range(spec.ACTIVATION_EXIT_DELAY + 1):
+    for _ in range(spec.MAX_SEED_LOOKAHEAD + 1):
         next_epoch(spec, state)
 
     yield from run_process_registry_updates(spec, state)
@@ -73,7 +73,7 @@ def test_ejection(spec, state):
     # Mock an ejection
     state.validators[index].effective_balance = spec.EJECTION_BALANCE
 
-    for _ in range(spec.ACTIVATION_EXIT_DELAY + 1):
+    for _ in range(spec.MAX_SEED_LOOKAHEAD + 1):
         next_epoch(spec, state)
 
     yield from run_process_registry_updates(spec, state)