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outline general flow of naive attestation aggregation

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Dustin Brody 2019-12-06 16:05:11 +01:00 committed by tersec
parent 294db6aaca
commit e2c68e075f
1 changed files with 54 additions and 2 deletions
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56
beacon_chain/naive_attestation_aggregation.nim
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@ -1,8 +1,21 @@
# beacon_chain
# Copyright (c) 2018-2019 Status Research & Development GmbH
# Licensed and distributed under either of
# * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT).
# * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.
import
sequtils,
options, sequtils,
./spec/[datatypes, crypto, digest, helpers, validator],
./ssz
# TODO add tests
# TODO gossipsub validation lives somewhere, maybe here
# https://github.com/status-im/nim-beacon-chain/issues/122#issuecomment-562479965
# it's conceptually separate, sort of, but depends on beaconstate, so isn't a
# pure libp2p thing.
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.2/specs/validator/0_beacon-chain-validator.md#aggregation-selection
func get_slot_signature(state: BeaconState, slot: Slot, privkey: ValidatorPrivKey):
ValidatorSig =
@ -23,6 +36,45 @@ func is_aggregator(state: BeaconState, slot: Slot, index: uint64,
bytes_to_int(eth2hash(slot_signature.getBytes).data[0..7]) mod modulo == 0
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.2/specs/validator/0_beacon-chain-validator.md#aggregate-signature-1
func get_aggregate_signature(attestations: seq[Attestation]): ValidatorSig =
func get_aggregate_signature(attestations: openarray[Attestation]): ValidatorSig =
let signatures = mapIt(attestations, it.signature)
bls_aggregate_signatures(signatures)
func should_aggregate(
state: BeaconState, index: uint64, privkey: ValidatorPrivKey): bool =
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.2/specs/validator/0_beacon-chain-validator.md#aggregation-selection
# A validator is selected to aggregate based upon the return value of
# is_aggregator().
let slot = state.slot - 1 # TODO this isn't correct
# the "Construct aggregate" section seems to suggest it's from a previous
# slot.
doAssert slot < state.slot
is_aggregator(state, slot, index, get_slot_signature(state, slot, privkey))
func aggregate_attestations_naively*(
state: BeaconState, index: uint64, privkey: ValidatorPrivKey):
Option[Attestation] =
# Keep this code opt-in with clean entry point; if there's a part that
# mutates state, split that off and keep this separate.
# TODO alias CommitteeIndex to actual type then convert various uint64's here
# to it
# If the validator is selected to aggregate (`is_aggregator()`), they
# construct an aggregate attestation
if not should_aggregate(state, index, privkey):
return none(Attestation)
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.2/specs/validator/0_beacon-chain-validator.md#construct-aggregate
# Collect attestations seen via gossip during the slot that have an
# equivalent attestation_data to that constructed by the validator,
# and create an aggregate_attestation: Attestation with the following fields.
var aggregate_attestation = Attestation(
)
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.2/specs/validator/0_beacon-chain-validator.md#aggregate-signature-1
# Set aggregate_attestation.signature = aggregate_signature where
# aggregate_signature is obtained from get_aggregate_signature(...).
aggregate_attestation.signature = get_aggregate_signature([])
some(aggregate_attestation)