462 lines
18 KiB
Nim
462 lines
18 KiB
Nim
# beacon_chain
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# Copyright (c) 2018-2024 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: [].}
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## This module contains signature verification helpers corresponding to those
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## in signatures.nim, for use with signature sets / batch signature verification
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## The functions follow the same structure and use the same arguments, except
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## that the flow is split into separate collection and verification steps.
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import
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# Status lib
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blscurve,
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stew/byteutils,
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results,
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taskpools,
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bearssl/rand,
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# Internal
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"."/[helpers, beaconstate, forks, signatures],
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"."/datatypes/[altair, bellatrix, phase0]
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export results, rand, altair, phase0, taskpools, signatures
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type
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TaskPoolPtr* = Taskpool
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BatchVerifier* = object
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sigVerifCache*: BatchedBLSVerifierCache
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## A cache for batch BLS signature verification contexts
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rng*: ref HmacDrbgContext
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## A reference to the Nimbus application-wide RNG
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taskpool*: TaskPoolPtr
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proc init*(
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T: type BatchVerifier, rng: ref HmacDrbgContext,
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taskpool: TaskPoolPtr): BatchVerifier =
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BatchVerifier(
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sigVerifCache: BatchedBLSVerifierCache.init(taskpool),
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rng: rng,
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taskpool: taskpool,
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)
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proc new*(
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T: type BatchVerifier, rng: ref HmacDrbgContext,
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taskpool: TaskPoolPtr): ref BatchVerifier =
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(ref BatchVerifier)(
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sigVerifCache: BatchedBLSVerifierCache.init(taskpool),
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rng: rng,
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taskpool: taskpool,
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)
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func `$`*(s: SignatureSet): string =
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"(pubkey: 0x" & s.pubkey.toHex() &
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", signing_root: 0x" & s.message.toHex() &
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", signature: 0x" & s.signature.toHex() & ')'
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# Important:
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# - Due to lazy loading, when we do crypto verification
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# and only then state-transition verification,
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# there is no guarantee that pubkeys and signatures received are valid
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# unlike when Nimbus did eager loading which ensured they were correct beforehand
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func init(T: type SignatureSet,
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pubkey: CookedPubKey, signing_root: Eth2Digest,
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signature: CookedSig): T =
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## Add a new signature set triplet (pubkey, message, signature)
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## to a collection of signature sets for batch verification.
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(
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blscurve.PublicKey(pubkey),
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signing_root.data,
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blscurve.Signature(signature)
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)
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func aggregateAttesters(
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validatorIndices: openArray[uint64|ValidatorIndex],
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validatorKeys: auto,
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): Result[CookedPubKey, cstring] =
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if validatorIndices.len == 0:
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# Aggregation spec requires non-empty collection
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# - https://tools.ietf.org/html/draft-irtf-cfrg-bls-signature-04
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# Consensus specs require at least one attesting index in attestation
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# - https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.6/specs/phase0/beacon-chain.md#is_valid_indexed_attestation
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return err("aggregateAttesters: no attesting indices")
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let
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firstKey = validatorKeys.load(validatorIndices[0]).valueOr:
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return err("aggregateAttesters: invalid attesting index")
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var attestersAgg{.noinit.}: AggregatePublicKey
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attestersAgg.init(firstKey)
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for i in 1 ..< validatorIndices.len:
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let key = validatorKeys.load(validatorIndices[i]).valueOr:
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return err("aggregateAttesters: invalid attesting index")
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attestersAgg.aggregate(key)
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ok(finish(attestersAgg))
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func aggregateAttesters(
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validatorIndices: openArray[uint64|ValidatorIndex],
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bits: auto,
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validatorKeys: auto,
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): Result[CookedPubKey, cstring] =
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if validatorIndices.len == 0:
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# Aggregation spec requires non-empty collection
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# - https://tools.ietf.org/html/draft-irtf-cfrg-bls-signature-04
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# Consensus specs require at least one attesting index in attestation
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# - https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.6/specs/phase0/beacon-chain.md#is_valid_indexed_attestation
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return err("aggregateAttesters: no attesting indices")
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var attestersAgg{.noinit.}: AggregatePublicKey
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var inited = false
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for i in 0..<bits.len:
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if bits[i]:
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let key = validatorKeys.load(validatorIndices[i]).valueOr:
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return err("aggregateAttesters: invalid attesting index")
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if inited:
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attestersAgg.aggregate(key)
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else:
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attestersAgg = AggregatePublicKey.init(key)
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inited = true
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if not inited:
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return err("aggregateAttesters:no attesting indices")
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ok(finish(attestersAgg))
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# Public API
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# ------------------------------------------------------
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# See also: verify_slot_signature
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func slot_signature_set*(
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fork: Fork, genesis_validators_root: Eth2Digest, slot: Slot,
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pubkey: CookedPubKey, signature: CookedSig): SignatureSet =
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let signing_root = compute_slot_signing_root(
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fork, genesis_validators_root, slot)
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SignatureSet.init(pubkey, signing_root, signature)
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# See also: verify_epoch_signature
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func epoch_signature_set*(
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fork: Fork, genesis_validators_root: Eth2Digest, epoch: Epoch,
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pubkey: CookedPubKey, signature: CookedSig): SignatureSet =
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let signing_root = compute_epoch_signing_root(
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fork, genesis_validators_root, epoch)
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SignatureSet.init(pubkey, signing_root, signature)
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# See also: verify_block_signature
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func block_signature_set*(
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fork: Fork, genesis_validators_root: Eth2Digest, slot: Slot,
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blck: Eth2Digest | SomeForkyBeaconBlock | BeaconBlockHeader,
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pubkey: CookedPubKey, signature: CookedSig): SignatureSet =
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let signing_root = compute_block_signing_root(
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fork, genesis_validators_root, slot, blck)
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SignatureSet.init(pubkey, signing_root, signature)
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# See also: verify_aggregate_and_proof_signature
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func aggregate_and_proof_signature_set*(
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fork: Fork, genesis_validators_root: Eth2Digest,
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aggregate_and_proof: AggregateAndProof,
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pubkey: CookedPubKey, signature: CookedSig): SignatureSet =
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let signing_root = compute_aggregate_and_proof_signing_root(
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fork, genesis_validators_root, aggregate_and_proof)
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SignatureSet.init(pubkey, signing_root, signature)
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# See also: verify_attestation_signature
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func attestation_signature_set*(
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fork: Fork, genesis_validators_root: Eth2Digest,
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attestation_data: AttestationData,
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pubkey: CookedPubKey, signature: CookedSig): SignatureSet =
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let signing_root = compute_attestation_signing_root(
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fork, genesis_validators_root, attestation_data)
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SignatureSet.init(pubkey, signing_root, signature)
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# See also: verify_voluntary_exit_signature
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func voluntary_exit_signature_set*(
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fork: Fork, genesis_validators_root: Eth2Digest,
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voluntary_exit: VoluntaryExit,
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pubkey: CookedPubKey, signature: CookedSig): SignatureSet =
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let signing_root = compute_voluntary_exit_signing_root(
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fork, genesis_validators_root, voluntary_exit)
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SignatureSet.init(pubkey, signing_root, signature)
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# See also: verify_sync_committee_message_signature
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func sync_committee_message_signature_set*(
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fork: Fork, genesis_validators_root: Eth2Digest,
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slot: Slot, block_root: Eth2Digest,
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pubkey: CookedPubKey, signature: CookedSig): SignatureSet =
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let signing_root = compute_sync_committee_message_signing_root(
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fork, genesis_validators_root, slot, block_root)
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SignatureSet.init(pubkey, signing_root, signature)
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# See also: verify_sync_committee_selection_proof
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func sync_committee_selection_proof_set*(
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fork: Fork, genesis_validators_root: Eth2Digest,
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slot: Slot, subcommittee_index: SyncSubcommitteeIndex,
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pubkey: CookedPubKey, signature: CookedSig): SignatureSet =
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let signing_root = compute_sync_committee_selection_proof_signing_root(
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fork, genesis_validators_root, slot, subcommittee_index)
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SignatureSet.init(pubkey, signing_root, signature)
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func contribution_and_proof_signature_set*(
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fork: Fork, genesis_validators_root: Eth2Digest,
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msg: ContributionAndProof,
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pubkey: CookedPubKey, signature: CookedSig): SignatureSet =
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let signing_root = compute_contribution_and_proof_signing_root(
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fork, genesis_validators_root, msg)
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SignatureSet.init(pubkey, signing_root, signature)
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func bls_to_execution_change_signature_set*(
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genesisFork: Fork, genesis_validators_root: Eth2Digest,
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msg: BLSToExecutionChange,
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pubkey: CookedPubKey, signature: CookedSig): SignatureSet =
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let signing_root = compute_bls_to_execution_change_signing_root(
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genesisFork, genesis_validators_root, msg)
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SignatureSet.init(pubkey, signing_root, signature)
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proc collectSignatureSets*(
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sigs: var seq[SignatureSet],
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signed_block: ForkySignedBeaconBlock,
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validatorKeys: openArray[ImmutableValidatorData2],
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state: ForkedHashedBeaconState,
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genesis_fork: Fork,
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capella_fork_version: Version,
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cache: var StateCache): Result[void, cstring] =
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## Collect all signature verifications that process_block would normally do
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## except deposits, in one go.
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##
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## This includes
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## - Block proposer
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## - Randao Reaveal
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## - Proposer slashings
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## - Attester slashings
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## - Attestations
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## - VoluntaryExits
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## - SyncCommittee (Altair+)
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## - BLS to execution changes (Capella+)
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##
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## We do not include deposits as they can be invalid while still leaving the
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## block valid
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# Metadata
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# ----------------------------------------------------
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mixin load
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let
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fork = getStateField(state, fork)
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genesis_validators_root = getStateField(state, genesis_validators_root)
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proposer_index = signed_block.message.proposer_index
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proposer_key = validatorKeys.load(proposer_index).valueOr:
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return err("collectSignatureSets: invalid proposer index")
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epoch = signed_block.message.slot.epoch()
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doAssert genesis_fork.previous_version == genesis_fork.current_version
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# 1. Block proposer
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# ----------------------------------------------------
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sigs.add block_signature_set(
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fork, genesis_validators_root,
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signed_block.message.slot, signed_block.root,
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proposer_key, signed_block.signature.load.valueOr do:
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return err("collectSignatureSets: cannot load signature"))
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# 2. Randao Reveal
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# ----------------------------------------------------
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sigs.add epoch_signature_set(
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fork, genesis_validators_root, epoch, proposer_key,
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signed_block.message.body.randao_reveal.load().valueOr do:
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return err("collectSignatureSets: cannot load randao"))
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# 3. Proposer slashings
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# ----------------------------------------------------
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# Denial-of-service:
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# SSZ deserialization guarantees that blocks received from random sources
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# including peer or RPC
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# have at most MAX_PROPOSER_SLASHINGS proposer slashings.
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for i in 0 ..< signed_block.message.body.proposer_slashings.len:
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# don't use "items" for iterating over large type
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# due to https://github.com/nim-lang/Nim/issues/14421
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# fixed in 1.4.2
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# Alias
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template slashing: untyped = signed_block.message.body.proposer_slashings[i]
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# Proposed block 1
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block:
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let
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header = slashing.signed_header_1
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key = validatorKeys.load(header.message.proposer_index).valueOr:
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return err("collectSignatureSets: invalid slashing proposer index 1")
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sigs.add block_signature_set(
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fork, genesis_validators_root, header.message.slot, header.message,
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key, header.signature.load().valueOr do:
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return err(
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"collectSignatureSets: cannot load proposer slashing 1 signature"))
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# Conflicting block 2
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block:
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let
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header = slashing.signed_header_2
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key = validatorKeys.load(header.message.proposer_index).valueOr:
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return err("collectSignatureSets: invalid slashing proposer index 2")
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sigs.add block_signature_set(
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fork, genesis_validators_root, header.message.slot, header.message,
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key, header.signature.load().valueOr do:
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return err(
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"collectSignatureSets: cannot load proposer slashing 2 signature"))
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# 4. Attester slashings
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# ----------------------------------------------------
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# Denial-of-service:
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# SSZ deserialization guarantees that blocks received from random sources
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# including peer or RPC
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# have at most MAX_ATTESTER_SLASHINGS attester slashings.
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for i in 0 ..< signed_block.message.body.attester_slashings.len:
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# don't use "items" for iterating over large type
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# due to https://github.com/nim-lang/Nim/issues/14421
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# fixed in 1.4.2
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# Alias
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template slashing: untyped = signed_block.message.body.attester_slashings[i]
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# Attestation 1
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block:
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let
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key = ? aggregateAttesters(
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slashing.attestation_1.attesting_indices.asSeq(), validatorKeys)
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sig = slashing.attestation_1.signature.load().valueOr:
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return err("Invalid attestation slashing signature 1")
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sigs.add attestation_signature_set(
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fork, genesis_validators_root, slashing.attestation_1.data, key, sig)
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# Conflicting attestation 2
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block:
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let
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key = ? aggregateAttesters(
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slashing.attestation_2.attesting_indices.asSeq(), validatorKeys)
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sig = slashing.attestation_2.signature.load().valueOr:
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return err("Invalid attestation slashing signature 2")
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sigs.add attestation_signature_set(
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fork, genesis_validators_root, slashing.attestation_2.data, key, sig)
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# 5. Attestations
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# ----------------------------------------------------
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# Denial-of-service:
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# SSZ deserialization guarantees that blocks received from random sources
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# including peer or RPC
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# have at most MAX_ATTESTATIONS attestations.
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for i in 0 ..< signed_block.message.body.attestations.len:
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# don't use "items" for iterating over large type
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# due to https://github.com/nim-lang/Nim/issues/14421
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# fixed in 1.4.2
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template attestation: untyped = signed_block.message.body.attestations[i]
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let
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key = ? aggregateAttesters(
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get_attesting_indices(
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state, attestation.data, attestation.aggregation_bits, cache),
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validatorKeys)
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sig = attestation.signature.load().valueOr:
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return err("Invalid attestation signature")
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sigs.add attestation_signature_set(
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fork, genesis_validators_root, attestation.data, key, sig)
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# 6. VoluntaryExits
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# ----------------------------------------------------
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# Denial-of-service:
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# SSZ deserialization guarantees that blocks received from random sources
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# including peer or RPC
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# have at most MAX_VOLUNTARY_EXITS voluntary exits.
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if signed_block.message.body.voluntary_exits.len > 0:
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let voluntary_exit_fork = withConsensusFork(state.kind):
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consensusFork.voluntary_exit_signature_fork(fork, capella_fork_version)
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for i in 0 ..< signed_block.message.body.voluntary_exits.len:
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# don't use "items" for iterating over large type
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# due to https://github.com/nim-lang/Nim/issues/14421
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# fixed in 1.4.2
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template volex: untyped = signed_block.message.body.voluntary_exits[i]
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let key = validatorKeys.load(volex.message.validator_index).valueOr:
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return err("collectSignatureSets: invalid voluntary exit")
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sigs.add voluntary_exit_signature_set(
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# https://eips.ethereum.org/EIPS/eip-7044
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# https://github.com/ethereum/consensus-specs/blob/v1.4.0/specs/deneb/beacon-chain.md#modified-process_voluntary_exit
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voluntary_exit_fork, genesis_validators_root, volex.message, key,
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volex.signature.load.valueOr do:
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return err(
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"collectSignatureSets: cannot load voluntary exit signature"))
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block:
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when signed_block is phase0.SignedBeaconBlock:
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discard
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else:
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# 7. SyncAggregate
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# ----------------------------------------------------
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withState(state):
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when consensusFork >= ConsensusFork.Altair:
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if signed_block.message.body.sync_aggregate.sync_committee_bits.isZeros:
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if signed_block.message.body.sync_aggregate.sync_committee_signature != ValidatorSig.infinity():
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return err("collectSignatureSets: empty sync aggregates need signature of point at infinity")
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else:
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let
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current_sync_committee =
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forkyState.data.get_sync_committee_cache(cache).current_sync_committee
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previous_slot = max(forkyState.data.slot, Slot(1)) - 1
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beacon_block_root = get_block_root_at_slot(forkyState.data, previous_slot)
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pubkey = ? aggregateAttesters(
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current_sync_committee,
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signed_block.message.body.sync_aggregate.sync_committee_bits,
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validatorKeys)
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sigs.add sync_committee_message_signature_set(
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fork, genesis_validators_root, previous_slot, beacon_block_root,
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pubkey,
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signed_block.message.body.sync_aggregate.sync_committee_signature.load().valueOr do:
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return err("collectSignatureSets: cannot load signature"))
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block:
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# 8. BLS to execution changes
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when typeof(signed_block).kind >= ConsensusFork.Capella:
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withState(state):
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when consensusFork >= ConsensusFork.Capella:
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for bls_change in signed_block.message.body.bls_to_execution_changes:
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let sig = bls_change.signature.load.valueOr:
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return err("collectSignatureSets: cannot load BLS to execution change signature")
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# Otherwise, expensive loadWithCache can be spammed with irrelevant pubkeys
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? check_bls_to_execution_change(
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genesis_fork, forkyState.data, bls_change, {skipBlsValidation})
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let validator_pubkey =
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bls_change.message.from_bls_pubkey.loadWithCache.valueOr:
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return err("collectSignatureSets: cannot load BLS to execution change pubkey")
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sigs.add bls_to_execution_change_signature_set(
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genesis_fork, genesis_validators_root, bls_change.message,
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validator_pubkey, sig)
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ok()
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proc batchVerify*(verifier: var BatchVerifier, sigs: openArray[SignatureSet]): bool =
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let bytes = verifier.rng[].generate(array[32, byte])
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verifier.taskpool.batchVerify(verifier.sigVerifCache, sigs, bytes)
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