[WIP] move attestation index outside signed message

pysetup/spec_builders/phase0.py

@@ -98,8 +98,8 @@ def wrapper(*args, **kw):  # type: ignore
 
 _get_attesting_indices = get_attesting_indices
 get_attesting_indices = cache_this(
-    lambda state, data, bits: (
+    lambda state, attestation: (
         state.randao_mixes.hash_tree_root(),
-        state.validators.hash_tree_root(), data.hash_tree_root(), bits.hash_tree_root()
+        state.validators.hash_tree_root(), attestation.hash_tree_root()
     ),
     _get_attesting_indices, lru_size=SLOTS_PER_EPOCH * MAX_COMMITTEES_PER_SLOT * 3)'''

specs/_features/custody_game/beacon-chain.md

@@ -401,7 +401,7 @@ def process_chunk_challenge(state: BeaconState, challenge: CustodyChunkChallenge
     # Verify responder is slashable
     assert is_slashable_validator(responder, get_current_epoch(state))
     # Verify the responder participated in the attestation
-    attesters = get_attesting_indices(state, challenge.attestation.data, challenge.attestation.aggregation_bits)
+    attesters = get_attesting_indices(state, challenge)
     assert challenge.responder_index in attesters
     # Verify shard transition is correctly given
     assert hash_tree_root(challenge.shard_transition) == challenge.attestation.data.shard_transition_root
@@ -594,7 +594,7 @@ def process_custody_slashing(state: BeaconState, signed_custody_slashing: Signed
     assert len(custody_slashing.data) == shard_transition.shard_block_lengths[custody_slashing.data_index]
     assert hash_tree_root(custody_slashing.data) == shard_transition.shard_data_roots[custody_slashing.data_index]
     # Verify existence and participation of claimed malefactor
-    attesters = get_attesting_indices(state, attestation.data, attestation.aggregation_bits)
+    attesters = get_attesting_indices(state, attestation)
     assert custody_slashing.malefactor_index in attesters
 
     # Verify the malefactor custody key

specs/_features/eip7549/beacon-chain.md

@@ -0,0 +1,64 @@
+# EIP-7549 -- The Beacon Chain
+
+## Table of contents
+
+<!-- TOC -->
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+
+- [Introduction](#introduction)
+- [Containers](#containers)
+  - [Extended containers](#extended-containers)
+    - [AttestationData](#attestationdata)
+    - [Attestation](#attestation)
+- [Helper functions](#helper-functions)
+  - [Beacon state accessors](#beacon-state-accessors)
+    - [Modified `get_attestation_index`](#modified-get_attestation_index)
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+<!-- /TOC -->
+
+## Introduction
+
+This is the beacon chain specification to move the attestation committee index outside of the signed message. For motivation, refer to [EIP-7549](https://github.com/ethereum/EIPs/pull/7944).
+
+*Note:* This specification is built upon [Deneb](../../deneb/beacon_chain.md) and is under active development.
+
+## Containers
+
+### Extended containers
+
+#### AttestationData
+
+```python
+class AttestationData(Container):
+    slot: Slot
+    # index: CommitteeIndex  # [Modified in EIP7549]
+    # LMD GHOST vote
+    beacon_block_root: Root
+    # FFG vote
+    source: Checkpoint
+    target: Checkpoint
+```
+
+#### Attestation
+
+```python
+class Attestation(Container):
+    aggregation_bits: Bitlist[MAX_VALIDATORS_PER_COMMITTEE]
+    data: AttestationData
+    index: CommitteeIndex  # [New in EIP7549]
+    signature: BLSSignature
+```
+
+## Helper functions
+
+### Beacon state accessors
+
+#### Modified `get_attestation_index`
+
+```python
+def get_attestation_index(attestation: Attestation) -> CommitteeIndex:
+    return attestation.index
+```
+

specs/altair/beacon-chain.md

@@ -496,7 +496,7 @@ def process_attestation(state: BeaconState, attestation: Attestation) -> None:
         epoch_participation = state.previous_epoch_participation
 
     proposer_reward_numerator = 0
-    for index in get_attesting_indices(state, data, attestation.aggregation_bits):
+    for index in get_attesting_indices(state, attestation):
         for flag_index, weight in enumerate(PARTICIPATION_FLAG_WEIGHTS):
             if flag_index in participation_flag_indices and not has_flag(epoch_participation[index], flag_index):
                 epoch_participation[index] = add_flag(epoch_participation[index], flag_index)

specs/altair/fork.md

@@ -69,7 +69,7 @@ def translate_participation(state: BeaconState, pending_attestations: Sequence[p
 
         # Apply flags to all attesting validators
         epoch_participation = state.previous_epoch_participation
-        for index in get_attesting_indices(state, data, attestation.aggregation_bits):
+        for index in get_attesting_indices(state, attestation):
             for flag_index in participation_flag_indices:
                 epoch_participation[index] = add_flag(epoch_participation[index], flag_index)
 

specs/deneb/beacon-chain.md

@@ -316,12 +316,13 @@ def verify_and_notify_new_payload(self: ExecutionEngine,
 ```python
 def process_attestation(state: BeaconState, attestation: Attestation) -> None:
     data = attestation.data
+    index = get_attestation_index(attestation)
     assert data.target.epoch in (get_previous_epoch(state), get_current_epoch(state))
     assert data.target.epoch == compute_epoch_at_slot(data.slot)
     assert data.slot + MIN_ATTESTATION_INCLUSION_DELAY <= state.slot  # [Modified in Deneb:EIP7045]
-    assert data.index < get_committee_count_per_slot(state, data.target.epoch)
+    assert index < get_committee_count_per_slot(state, data.target.epoch)
 
-    committee = get_beacon_committee(state, data.slot, data.index)
+    committee = get_beacon_committee(state, data.slot, index)
     assert len(attestation.aggregation_bits) == len(committee)
 
     # Participation flag indices
@@ -337,7 +338,7 @@ def process_attestation(state: BeaconState, attestation: Attestation) -> None:
         epoch_participation = state.previous_epoch_participation
 
     proposer_reward_numerator = 0
-    for index in get_attesting_indices(state, data, attestation.aggregation_bits):
+    for index in get_attesting_indices(state, attestation):
         for flag_index, weight in enumerate(PARTICIPATION_FLAG_WEIGHTS):
             if flag_index in participation_flag_indices and not has_flag(epoch_participation[index], flag_index):
                 epoch_participation[index] = add_flag(epoch_participation[index], flag_index)

specs/deneb/p2p-interface.md

@@ -23,8 +23,9 @@ The specification of these changes continues in the same format as the network s
     - [Topics and messages](#topics-and-messages)
       - [Global topics](#global-topics)
         - [`beacon_block`](#beacon_block)
-        - [`blob_sidecar_{subnet_id}`](#blob_sidecar_subnet_id)
         - [`beacon_aggregate_and_proof`](#beacon_aggregate_and_proof)
+      - [Blob subnets](#blob-subnets)
+        - [`blob_sidecar_{subnet_id}`](#blob_sidecar_subnet_id)
       - [Attestation subnets](#attestation-subnets)
         - [`beacon_attestation_{subnet_id}`](#beacon_attestation_subnet_id)
     - [Transitioning the gossip](#transitioning-the-gossip)
@@ -133,8 +134,6 @@ The new topics along with the type of the `data` field of a gossipsub message ar
 
 ##### Global topics
 
-Deneb introduces new global topics for blob sidecars.
-
 ###### `beacon_block`
 
 The *type* of the payload of this topic changes to the (modified) `SignedBeaconBlock` found in Deneb.
@@ -146,6 +145,25 @@ New validation:
 - _[REJECT]_ The length of KZG commitments is less than or equal to the limitation defined in Consensus Layer --
   i.e. validate that `len(body.signed_beacon_block.message.blob_kzg_commitments) <= MAX_BLOBS_PER_BLOCK`
 
+###### `beacon_aggregate_and_proof`
+
+*[Modified in Deneb:EIP7045]*
+
+The following validation is removed:
+* _[IGNORE]_ `aggregate.data.slot` is within the last `ATTESTATION_PROPAGATION_SLOT_RANGE` slots (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) --
+  i.e. `aggregate.data.slot + ATTESTATION_PROPAGATION_SLOT_RANGE >= current_slot >= aggregate.data.slot`
+  (a client MAY queue future aggregates for processing at the appropriate slot).
+
+The following validations are added in its place:
+* _[IGNORE]_ `aggregate.data.slot` is equal to or earlier than the `current_slot` (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) --
+  i.e. `aggregate.data.slot <= current_slot`
+  (a client MAY queue future aggregates for processing at the appropriate slot).
+* _[IGNORE]_ the epoch of `aggregate.data.slot` is either the current or previous epoch
+  (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) --
+  i.e. `compute_epoch_at_slot(aggregate.data.slot) in (get_previous_epoch(state), get_current_epoch(state))`
+
+##### Blob subnets
+
 ###### `blob_sidecar_{subnet_id}`
 
 *[New in Deneb:EIP4844]*
@@ -169,23 +187,6 @@ The following validations MUST pass before forwarding the `blob_sidecar` on the
 - _[REJECT]_ The sidecar is proposed by the expected `proposer_index` for the block's slot in the context of the current shuffling (defined by `block_header.parent_root`/`block_header.slot`).
   If the `proposer_index` cannot immediately be verified against the expected shuffling, the sidecar MAY be queued for later processing while proposers for the block's branch are calculated -- in such a case _do not_ `REJECT`, instead `IGNORE` this message.
 
-###### `beacon_aggregate_and_proof`
-
-*[Modified in Deneb:EIP7045]*
-
-The following validation is removed:
-* _[IGNORE]_ `aggregate.data.slot` is within the last `ATTESTATION_PROPAGATION_SLOT_RANGE` slots (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) --
-  i.e. `aggregate.data.slot + ATTESTATION_PROPAGATION_SLOT_RANGE >= current_slot >= aggregate.data.slot`
-  (a client MAY queue future aggregates for processing at the appropriate slot).
-
-The following validations are added in its place:
-* _[IGNORE]_ `aggregate.data.slot` is equal to or earlier than the `current_slot` (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) --
-  i.e. `aggregate.data.slot <= current_slot`
-  (a client MAY queue future aggregates for processing at the appropriate slot).
-* _[IGNORE]_ the epoch of `aggregate.data.slot` is either the current or previous epoch
-  (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) --
-  i.e. `compute_epoch_at_slot(aggregate.data.slot) in (get_previous_epoch(state), get_current_epoch(state))`
-
 ##### Attestation subnets
 
 ###### `beacon_attestation_{subnet_id}`
@@ -252,6 +253,10 @@ Per `context = compute_fork_digest(fork_version, genesis_validators_root)`:
 
 No more than `MAX_REQUEST_BLOCKS_DENEB` may be requested at a time.
 
+*[Modified in Deneb:EIP4844]*
+Clients SHOULD include a block in the response as soon as it passes the gossip validation rules.
+Clients SHOULD NOT respond with blocks that fail the beacon chain state transition.
+
 ##### BlobSidecarsByRoot v1
 
 **Protocol ID:** `/eth2/beacon_chain/req/blob_sidecars_by_root/1/`
@@ -300,6 +305,10 @@ Clients MUST support requesting sidecars since `minimum_request_epoch`, where `m
 Clients MUST respond with at least one sidecar, if they have it.
 Clients MAY limit the number of blocks and sidecars in the response.
 
+Clients SHOULD include a sidecar in the response as soon as it passes the gossip validation rules.
+Clients SHOULD NOT respond with sidecars related to blocks that fail gossip validation rules.
+Clients SHOULD NOT respond with sidecars related to blocks that fail the beacon chain state transition
+
 ##### BlobSidecarsByRange v1
 
 **Protocol ID:** `/eth2/beacon_chain/req/blob_sidecars_by_range/1/`

specs/phase0/beacon-chain.md

@@ -100,6 +100,7 @@
     - [`get_domain`](#get_domain)
     - [`get_indexed_attestation`](#get_indexed_attestation)
     - [`get_attesting_indices`](#get_attesting_indices)
+    - [`get_attestation_index`](#get_attestation_index)
   - [Beacon state mutators](#beacon-state-mutators)
     - [`increase_balance`](#increase_balance)
     - [`decrease_balance`](#decrease_balance)
@@ -1082,7 +1083,7 @@ def get_indexed_attestation(state: BeaconState, attestation: Attestation) -> Ind
     """
     Return the indexed attestation corresponding to ``attestation``.
     """
-    attesting_indices = get_attesting_indices(state, attestation.data, attestation.aggregation_bits)
+    attesting_indices = get_attesting_indices(state, attestation)
 
     return IndexedAttestation(
         attesting_indices=sorted(attesting_indices),
@@ -1094,14 +1095,19 @@ def get_indexed_attestation(state: BeaconState, attestation: Attestation) -> Ind
 #### `get_attesting_indices`
 
 ```python
-def get_attesting_indices(state: BeaconState,
-                          data: AttestationData,
-                          bits: Bitlist[MAX_VALIDATORS_PER_COMMITTEE]) -> Set[ValidatorIndex]:
+def get_attesting_indices(state: BeaconState, attestation: Attestation) -> Set[ValidatorIndex]:
     """
     Return the set of attesting indices corresponding to ``data`` and ``bits``.
     """
-    committee = get_beacon_committee(state, data.slot, data.index)
-    return set(index for i, index in enumerate(committee) if bits[i])
+    committee = get_beacon_committee(state, attestation.data.slot, get_attestation_index(attestation))
+    return set(index for i, index in enumerate(committee) if attestation.aggregation_bits[i])
+```
+
+#### `get_attestation_index`
+
+```python
+def get_attestation_index(attestation: Attestation) -> CommitteeIndex:
+    return attestation.data.index
 ```
 
 ### Beacon state mutators
@@ -1339,7 +1345,7 @@ def get_unslashed_attesting_indices(state: BeaconState,
                                     attestations: Sequence[PendingAttestation]) -> Set[ValidatorIndex]:
     output = set()  # type: Set[ValidatorIndex]
     for a in attestations:
-        output = output.union(get_attesting_indices(state, a.data, a.aggregation_bits))
+        output = output.union(get_attesting_indices(state, a))
     return set(filter(lambda index: not state.validators[index].slashed, output))
 ```
 
@@ -1512,7 +1518,7 @@ def get_inclusion_delay_deltas(state: BeaconState) -> Tuple[Sequence[Gwei], Sequ
     for index in get_unslashed_attesting_indices(state, matching_source_attestations):
         attestation = min([
             a for a in matching_source_attestations
-            if index in get_attesting_indices(state, a.data, a.aggregation_bits)
+            if index in get_attesting_indices(state, a)
         ], key=lambda a: a.inclusion_delay)
         rewards[attestation.proposer_index] += get_proposer_reward(state, index)
         max_attester_reward = Gwei(get_base_reward(state, index) - get_proposer_reward(state, index))

specs/phase0/p2p-interface.md

@@ -354,7 +354,7 @@ The `beacon_aggregate_and_proof` topic is used to propagate aggregated attestati
 to subscribing nodes (typically validators) to be included in future blocks.
 
 The following validations MUST pass before forwarding the `signed_aggregate_and_proof` on the network.
-(We define the following for convenience -- `aggregate_and_proof = signed_aggregate_and_proof.message` and `aggregate = aggregate_and_proof.aggregate`)
+(We define the following for convenience -- `aggregate_and_proof = signed_aggregate_and_proof.message`, `aggregate = aggregate_and_proof.aggregate` and `index = get_attestation_index(aggregate)`)
 - _[IGNORE]_ `aggregate.data.slot` is within the last `ATTESTATION_PROPAGATION_SLOT_RANGE` slots (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) --
   i.e. `aggregate.data.slot + ATTESTATION_PROPAGATION_SLOT_RANGE >= current_slot >= aggregate.data.slot`
   (a client MAY queue future aggregates for processing at the appropriate slot).
@@ -364,12 +364,11 @@ The following validations MUST pass before forwarding the `signed_aggregate_and_
   (via aggregate gossip, within a verified block, or through the creation of an equivalent aggregate locally).
 - _[IGNORE]_ The `aggregate` is the first valid aggregate received for the aggregator
   with index `aggregate_and_proof.aggregator_index` for the epoch `aggregate.data.target.epoch`.
-- _[REJECT]_ The attestation has participants --
-  that is, `len(get_attesting_indices(state, aggregate.data, aggregate.aggregation_bits)) >= 1`.
+- _[REJECT]_ The attestation has participants -- that is, `len(get_attesting_indices(state, aggregate)) >= 1`.
 - _[REJECT]_ `aggregate_and_proof.selection_proof` selects the validator as an aggregator for the slot --
-  i.e. `is_aggregator(state, aggregate.data.slot, aggregate.data.index, aggregate_and_proof.selection_proof)` returns `True`.
+  i.e. `is_aggregator(state, aggregate.data.slot, index, aggregate_and_proof.selection_proof)` returns `True`.
 - _[REJECT]_ The aggregator's validator index is within the committee --
-  i.e. `aggregate_and_proof.aggregator_index in get_beacon_committee(state, aggregate.data.slot, aggregate.data.index)`.
+  i.e. `aggregate_and_proof.aggregator_index in get_beacon_committee(state, aggregate.data.slot, index)`.
 - _[REJECT]_ The `aggregate_and_proof.selection_proof` is a valid signature
   of the `aggregate.data.slot` by the validator with index `aggregate_and_proof.aggregator_index`.
 - _[REJECT]_ The aggregator signature, `signed_aggregate_and_proof.signature`, is valid.
@@ -425,9 +424,10 @@ The `beacon_attestation_{subnet_id}` topics are used to propagate unaggregated a
 to the subnet `subnet_id` (typically beacon and persistent committees) to be aggregated before being gossiped to `beacon_aggregate_and_proof`.
 
 The following validations MUST pass before forwarding the `attestation` on the subnet.
-- _[REJECT]_ The committee index is within the expected range -- i.e. `data.index < get_committee_count_per_slot(state, data.target.epoch)`.
+(We define the following for convenience -- `index = get_attestation_index(attestation)`)
+- _[REJECT]_ The committee index is within the expected range -- i.e. `index < get_committee_count_per_slot(state, data.target.epoch)`.
 - _[REJECT]_ The attestation is for the correct subnet --
-  i.e. `compute_subnet_for_attestation(committees_per_slot, attestation.data.slot, attestation.data.index) == subnet_id`,
+  i.e. `compute_subnet_for_attestation(committees_per_slot, attestation.data.slot, index) == subnet_id`,
   where `committees_per_slot = get_committee_count_per_slot(state, attestation.data.target.epoch)`,
   which may be pre-computed along with the committee information for the signature check.
 - _[IGNORE]_ `attestation.data.slot` is within the last `ATTESTATION_PROPAGATION_SLOT_RANGE` slots
@@ -439,7 +439,7 @@ The following validations MUST pass before forwarding the `attestation` on the s
 - _[REJECT]_ The attestation is unaggregated --
   that is, it has exactly one participating validator (`len([bit for bit in attestation.aggregation_bits if bit]) == 1`, i.e. exactly 1 bit is set).
 - _[REJECT]_ The number of aggregation bits matches the committee size -- i.e.
-  `len(attestation.aggregation_bits) == len(get_beacon_committee(state, data.slot, data.index))`.
+  `len(attestation.aggregation_bits) == len(get_beacon_committee(state, data.slot, index))`.
 - _[IGNORE]_ There has been no other valid attestation seen on an attestation subnet
   that has an identical `attestation.data.target.epoch` and participating validator index.
 - _[REJECT]_ The signature of `attestation` is valid.
@@ -856,6 +856,9 @@ Clients MUST support requesting blocks since the latest finalized epoch.
 Clients MUST respond with at least one block, if they have it.
 Clients MAY limit the number of blocks in the response.
 
+Clients MAY include a block in the response as soon as it passes the gossip validation rules.
+Clients SHOULD NOT respond with blocks that fail the beacon chain state transition.
+
 `/eth2/beacon_chain/req/beacon_blocks_by_root/1/` is deprecated. Clients MAY respond with an empty list during the deprecation transition period.
 
 ##### Ping

specs/phase0/validator.md

@@ -494,7 +494,7 @@ Set `attestation.data = attestation_data` where `attestation_data` is the `Attes
 
 - Let `attestation.aggregation_bits` be a `Bitlist[MAX_VALIDATORS_PER_COMMITTEE]` of length `len(committee)`, where the bit of the index of the validator in the `committee` is set to `0b1`.
 
-*Note*: Calling `get_attesting_indices(state, attestation.data, attestation.aggregation_bits)` should return a list of length equal to 1, containing `validator_index`.
+*Note*: Calling `get_attesting_indices(state, attestation)` should return a list of length equal to 1, containing `validator_index`.
 
 ##### Aggregate signature
 

tests/core/pyspec/eth2spec/VERSION.txt

@@ -1 +1 @@
-1.4.0-beta.4
+1.4.0-beta.5