202 lines
8.1 KiB
Nim
202 lines
8.1 KiB
Nim
# beacon_chain
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# Copyright (c) 2018-2021 Status Research & Development GmbH
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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{.push raises: [Defect].}
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import
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std/[intsets],
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chronicles,
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../extras,
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../spec/[helpers, network, signatures, validator],
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../spec/datatypes/base,
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./block_pools_types, blockchain_dag
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export
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base, extras, block_pools_types
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# Spec functions implemented based on cached values instead of the full state
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func count_active_validators*(epochInfo: EpochRef): uint64 =
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epochInfo.shuffled_active_validator_indices.lenu64
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# https://github.com/ethereum/consensus-specs/blob/v1.1.0/specs/phase0/beacon-chain.md#get_committee_count_per_slot
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func get_committee_count_per_slot*(epochInfo: EpochRef): uint64 =
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get_committee_count_per_slot(count_active_validators(epochInfo))
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iterator get_committee_indices*(epochRef: EpochRef): CommitteeIndex =
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for i in 0'u64..<get_committee_count_per_slot(epochRef):
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yield CommitteeIndex(i)
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# https://github.com/ethereum/consensus-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#get_beacon_committee
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iterator get_beacon_committee*(
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epochRef: EpochRef, slot: Slot, index: CommitteeIndex): ValidatorIndex =
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# Return the beacon committee at ``slot`` for ``index``.
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let
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committees_per_slot = get_committee_count_per_slot(epochRef)
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for idx in compute_committee(
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epochRef.shuffled_active_validator_indices,
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(slot mod SLOTS_PER_EPOCH) * committees_per_slot +
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index.uint64,
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committees_per_slot * SLOTS_PER_EPOCH
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): yield idx
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# https://github.com/ethereum/consensus-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#get_beacon_committee
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func get_beacon_committee*(
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epochRef: EpochRef, slot: Slot, index: CommitteeIndex): seq[ValidatorIndex] =
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# Return the beacon committee at ``slot`` for ``index``.
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let
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committees_per_slot = get_committee_count_per_slot(epochRef)
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compute_committee(
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epochRef.shuffled_active_validator_indices,
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(slot mod SLOTS_PER_EPOCH) * committees_per_slot +
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index.uint64,
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committees_per_slot * SLOTS_PER_EPOCH
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)
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# https://github.com/ethereum/consensus-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#get_beacon_committee
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func get_beacon_committee_len*(
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epochRef: EpochRef, slot: Slot, index: CommitteeIndex): uint64 =
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# Return the number of members in the beacon committee at ``slot`` for ``index``.
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let
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committees_per_slot = get_committee_count_per_slot(epochRef)
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compute_committee_len(
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count_active_validators(epochRef),
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(slot mod SLOTS_PER_EPOCH) * committees_per_slot +
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index.uint64,
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committees_per_slot * SLOTS_PER_EPOCH
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)
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# https://github.com/ethereum/consensus-specs/blob/v1.0.1/specs/phase0/beacon-chain.md#get_attesting_indices
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iterator get_attesting_indices*(epochRef: EpochRef,
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data: AttestationData,
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bits: CommitteeValidatorsBits):
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ValidatorIndex =
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if bits.lenu64 != get_beacon_committee_len(epochRef, data.slot, data.index.CommitteeIndex):
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trace "get_attesting_indices: inconsistent aggregation and committee length"
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else:
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var i = 0
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for index in get_beacon_committee(epochRef, data.slot, data.index.CommitteeIndex):
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if bits[i]:
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yield index
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inc i
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func get_attesting_indices_one*(epochRef: EpochRef,
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data: AttestationData,
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bits: CommitteeValidatorsBits):
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Option[ValidatorIndex] =
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# A variation on get_attesting_indices that returns the validator index only
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# if only one validator index is set
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if bits.lenu64 != get_beacon_committee_len(epochRef, data.slot, data.index.CommitteeIndex):
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trace "get_attesting_indices: inconsistent aggregation and committee length"
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none(ValidatorIndex)
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else:
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var res = none(ValidatorIndex)
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var i = 0
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for index in get_beacon_committee(epochRef, data.slot, data.index.CommitteeIndex):
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if bits[i]:
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if res.isNone():
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res = some(index)
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else:
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return none(ValidatorIndex)
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inc i
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res
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# https://github.com/ethereum/consensus-specs/blob/v1.1.0/specs/phase0/beacon-chain.md#get_attesting_indices
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func get_attesting_indices*(epochRef: EpochRef,
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data: AttestationData,
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bits: CommitteeValidatorsBits):
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seq[ValidatorIndex] =
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# TODO sequtils2 mapIt
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for idx in get_attesting_indices(epochRef, data, bits):
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result.add(idx)
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# https://github.com/ethereum/consensus-specs/blob/v1.1.0/specs/phase0/beacon-chain.md#is_valid_indexed_attestation
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proc is_valid_indexed_attestation*(
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fork: Fork, genesis_validators_root: Eth2Digest,
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epochRef: EpochRef,
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attestation: SomeAttestation, flags: UpdateFlags): Result[void, cstring] =
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# This is a variation on `is_valid_indexed_attestation` that works directly
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# with an attestation instead of first constructing an `IndexedAttestation`
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# and then validating it - for the purpose of validating the signature, the
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# order doesn't matter and we can proceed straight to validating the
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# signature instead
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let sigs = attestation.aggregation_bits.countOnes()
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if sigs == 0:
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return err("is_valid_indexed_attestation: no attesting indices")
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# Verify aggregate signature
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if not (skipBLSValidation in flags or attestation.signature is TrustedSig):
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var
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pubkeys = newSeqOfCap[CookedPubKey](sigs)
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for index in get_attesting_indices(
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epochRef, attestation.data, attestation.aggregation_bits):
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pubkeys.add(epochRef.validatorKey(index).get())
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if not verify_attestation_signature(
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fork, genesis_validators_root, attestation.data,
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pubkeys, attestation.signature):
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return err("is_valid_indexed_attestation: signature verification failure")
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ok()
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func makeAttestationData*(
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epochRef: EpochRef, bs: BlockSlot,
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committee_index: CommitteeIndex): AttestationData =
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## Create an attestation / vote for the block `bs` using the
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## data in `epochRef` to fill in the rest of the fields.
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## `epochRef` is the epoch information corresponding to the `bs` advanced to
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## the slot we're attesting to.
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let
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slot = bs.slot
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current_epoch = slot.compute_epoch_at_slot()
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epoch_boundary_slot = compute_start_slot_at_epoch(current_epoch)
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epoch_boundary_block = bs.blck.atSlot(epoch_boundary_slot)
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doAssert current_epoch == epochRef.epoch
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# https://github.com/ethereum/consensus-specs/blob/v1.1.0/specs/phase0/validator.md#attestation-data
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AttestationData(
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slot: slot,
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index: committee_index.uint64,
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beacon_block_root: bs.blck.root,
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source: epochRef.current_justified_checkpoint,
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target: Checkpoint(
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epoch: current_epoch,
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root: epoch_boundary_block.blck.root
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)
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)
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# https://github.com/ethereum/consensus-specs/blob/v1.0.1/specs/phase0/validator.md#validator-assignments
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iterator get_committee_assignments*(
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epochRef: EpochRef, epoch: Epoch, validator_indices: IntSet):
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tuple[validatorIndices: IntSet,
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committeeIndex: CommitteeIndex,
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subnet_id: SubnetId, slot: Slot] =
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let
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committees_per_slot = get_committee_count_per_slot(epochRef)
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start_slot = compute_start_slot_at_epoch(epoch)
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for slot in start_slot ..< start_slot + SLOTS_PER_EPOCH:
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for index in 0'u64 ..< committees_per_slot:
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let
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idx = index.CommitteeIndex
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includedIndices =
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toIntSet(get_beacon_committee(epochRef, slot, idx)) *
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validator_indices
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if includedIndices.len > 0:
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yield (
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includedIndices, idx,
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compute_subnet_for_attestation(committees_per_slot, slot, idx),
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slot)
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func is_aggregator*(epochRef: EpochRef, slot: Slot, index: CommitteeIndex,
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slot_signature: ValidatorSig): bool =
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let
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committee_len = get_beacon_committee_len(epochRef, slot, index)
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return is_aggregator(committee_len, slot_signature)
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