Start making phase1 work in pyspec again
This commit is contained in:
protolambda
Danny Ryan
parent
ef936b94fe
commit
a33e01dab2
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@ -1129,19 +1129,13 @@ def process_slot(state: BeaconState) -> None:
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### Epoch processing
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*Note*: The `# @LabelHere` lines below are placeholders to show that code will be inserted here in a future phase.
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```python
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def process_epoch(state: BeaconState) -> None:
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process_justification_and_finalization(state)
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process_rewards_and_penalties(state)
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process_registry_updates(state)
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# @process_reveal_deadlines
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# @process_challenge_deadlines
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process_slashings(state)
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# @update_period_committee
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process_final_updates(state)
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# @after_process_final_updates
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```
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#### Helper functions
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@ -1425,16 +1419,11 @@ def process_operations(state: BeaconState, body: BeaconBlockBody) -> None:
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# Verify that outstanding deposits are processed up to the maximum number of deposits
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assert len(body.deposits) == min(MAX_DEPOSITS, state.eth1_data.deposit_count - state.eth1_deposit_index)
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for operations, function in (
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(body.proposer_slashings, process_proposer_slashing),
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(body.attester_slashings, process_attester_slashing),
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(body.attestations, process_attestation),
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(body.deposits, process_deposit),
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(body.voluntary_exits, process_voluntary_exit),
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# @process_shard_receipt_proofs
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):
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for operation in operations:
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function(state, operation)
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process_operations(body.proposer_slashings, process_proposer_slashing)
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process_operations(body.attester_slashings, process_attester_slashing)
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process_operations(body.attestations, process_attestations)
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process_operations(body.deposits, process_deposit)
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process_operations(body.voluntary_exits, process_voluntary_exit)
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```
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##### Proposer slashings
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@ -1,4 +1,4 @@
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# Ethereum 2.0 Phase 1 -- Crosslinks and Shard Data
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# Ethereum 2.0 Phase 1 -- The Beacon Chain for Shards
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**Notice**: This document is a work-in-progress for researchers and implementers.
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@ -6,53 +6,20 @@
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<!-- TOC -->
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- [Ethereum 2.0 Phase 1 -- Crosslinks and Shard Data](#ethereum-20-phase-1----crosslinks-and-shard-data)
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- [Table of contents](#table-of-contents)
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- [Introduction](#introduction)
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- [Configuration](#configuration)
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- [Misc](#misc)
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- [Containers](#containers)
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- [`ShardBlockWrapper`](#shardblockwrapper)
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- [`ShardSignableHeader`](#shardsignedheader)
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- [`ShardState`](#shardstate)
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- [`AttestationData`](#attestationdata)
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- [`ShardTransition`](#shardtransition)
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- [`Attestation`](#attestation)
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- [`AttestationAndCommittee`](#attestationandcommittee)
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- [`CompactCommittee`](#compactcommittee)
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- [`AttestationCustodyBitWrapper`](#attestationcustodybitwrapper)
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- [`PendingAttestation`](#pendingattestation)
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- [Helpers](#helpers)
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- [`get_online_validators`](#get_online_validators)
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- [`pack_compact_validator`](#pack_compact_validator)
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- [`committee_to_compact_committee`](#committee_to_compact_committee)
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- [`get_light_client_committee`](#get_light_client_committee)
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- [`get_indexed_attestation`](#get_indexed_attestation)
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- [`get_updated_gasprice`](#get_updated_gasprice)
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- [`is_valid_indexed_attestation`](#is_valid_indexed_attestation)
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- [`get_attestation_shard`](#get_attestation_shard)
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- [Beacon Chain Changes](#beacon-chain-changes)
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- [New beacon state fields](#new-beacon-state-fields)
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- [New beacon block data fields](#new-beacon-block-data-fields)
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- [Attestation processing](#attestation-processing)
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- [`validate_attestation`](#validate_attestation)
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- [`apply_shard_transition`](#apply_shard_transition)
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- [`process_attestations`](#process_attestations)
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- [Misc block post-processing](#misc-block-post-processing)
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- [Light client processing](#light-client-processing)
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- [Epoch transition](#epoch-transition)
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- [Fraud proofs](#fraud-proofs)
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- [Shard state transition function](#shard-state-transition-function)
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- [Honest committee member behavior](#honest-committee-member-behavior)
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TODO
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<!-- /TOC -->
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## Introduction
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This document describes the shard transition function (data layer only) and the shard fork choice rule as part of Phase 1 of Ethereum 2.0.
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This document describes the extensions made to the Phase 0 design of The Beacon Chain
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to facilitate the new shards as part of Phase 1 of Eth2.
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## Configuration
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Configuration is not namespaced. Instead it is strictly an extension;
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no constants of phase 0 change, but new constants are adopted for changing behaviors.
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### Misc
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| Name | Value | Unit | Duration |
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@ -111,7 +78,7 @@ class ShardState(Container):
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latest_block_root: Hash
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```
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### `AttestationData`
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### New `AttestationData`
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```python
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class AttestationData(Container):
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@ -144,7 +111,7 @@ class ShardTransition(Container):
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proposer_signature_aggregate: BLSSignature
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```
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### `Attestation`
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### New `Attestation`
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```python
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class Attestation(Container):
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@ -179,7 +146,7 @@ class AttestationCustodyBitWrapper(Container):
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bit: bool
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```
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### `PendingAttestation`
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### New `PendingAttestation`
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```python
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class PendingAttestation(Container):
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@ -190,17 +157,112 @@ class PendingAttestation(Container):
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crosslink_success: bool
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```
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## Helpers
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### `get_online_validators`
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### New extended `Validator`
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```python
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def get_online_indices(state: BeaconState) -> Set[ValidatorIndex]:
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active_validators = get_active_validator_indices(state, get_current_epoch(state))
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return set([i for i in active_validators if state.online_countdown[i] != 0])
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class Validator(Container):
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pubkey: BLSPubkey
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withdrawal_credentials: Hash # Commitment to pubkey for withdrawals
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effective_balance: Gwei # Balance at stake
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slashed: boolean
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# Status epochs
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activation_eligibility_epoch: Epoch # When criteria for activation were met
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activation_epoch: Epoch
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exit_epoch: Epoch
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withdrawable_epoch: Epoch # When validator can withdraw funds
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# TODO: older pre-proposal custody field additions, keep this?
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#
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# next_custody_secret_to_reveal is initialised to the custody period
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# (of the particular validator) in which the validator is activated
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# = get_custody_period_for_validator(...)
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next_custody_secret_to_reveal: uint64
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max_reveal_lateness: Epoch
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```
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### `pack_compact_validator`
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### New extended `BeaconBlock`
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```python
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class BeaconBlock(phase0.BeaconBlock):
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slot: Slot
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parent_root: Hash
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state_root: Hash
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body: BeaconBlockBody
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shard_transitions: Vector[ShardTransition, MAX_SHARDS]
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light_client_signature_bitfield: Bitlist[LIGHT_CLIENT_COMMITTEE_SIZE]
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light_client_signature: BLSSignature
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# TODO: older pre-proposal custody field additions, keep this?
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custody_chunk_challenges: List[CustodyChunkChallenge, PLACEHOLDER]
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custody_bit_challenges: List[CustodyBitChallenge, PLACEHOLDER]
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custody_responses: List[CustodyResponse, PLACEHOLDER]
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custody_key_reveals: List[CustodyKeyReveal, PLACEHOLDER]
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early_derived_secret_reveals: List[EarlyDerivedSecretReveal, PLACEHOLDER]
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signature: BLSSignature
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```
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### New extended `BeaconState`
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```python
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class BeaconState(phase0.BeaconState):
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# Versioning
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genesis_time: uint64
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slot: Slot
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fork: Fork
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# History
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latest_block_header: BeaconBlockHeader
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block_roots: Vector[Hash, SLOTS_PER_HISTORICAL_ROOT]
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state_roots: Vector[Hash, SLOTS_PER_HISTORICAL_ROOT]
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historical_roots: List[Hash, HISTORICAL_ROOTS_LIMIT]
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# Eth1
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eth1_data: Eth1Data
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eth1_data_votes: List[Eth1Data, SLOTS_PER_ETH1_VOTING_PERIOD]
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eth1_deposit_index: uint64
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# Registry
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validators: List[Validator, VALIDATOR_REGISTRY_LIMIT]
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balances: List[Gwei, VALIDATOR_REGISTRY_LIMIT]
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# Randomness
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randao_mixes: Vector[Hash, EPOCHS_PER_HISTORICAL_VECTOR]
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# Slashings
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slashings: Vector[Gwei, EPOCHS_PER_SLASHINGS_VECTOR] # Per-epoch sums of slashed effective balances
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# Attestations
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previous_epoch_attestations: List[PendingAttestation, MAX_ATTESTATIONS * SLOTS_PER_EPOCH]
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current_epoch_attestations: List[PendingAttestation, MAX_ATTESTATIONS * SLOTS_PER_EPOCH]
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# Finality
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justification_bits: Bitvector[JUSTIFICATION_BITS_LENGTH] # Bit set for every recent justified epoch
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previous_justified_checkpoint: Checkpoint # Previous epoch snapshot
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current_justified_checkpoint: Checkpoint
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finalized_checkpoint: Checkpoint
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# Phase 1
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shard_states: Vector[ShardState, MAX_SHARDS]
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online_countdown: Bytes[VALIDATOR_REGISTRY_LIMIT]
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current_light_committee: CompactCommittee
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next_light_committee: CompactCommittee
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# TODO older pre-proposal custody field additions, keep this?
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custody_chunk_challenge_records: List[CustodyChunkChallengeRecord, PLACEHOLDER]
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custody_bit_challenge_records: List[CustodyBitChallengeRecord, PLACEHOLDER]
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custody_challenge_index: uint64
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# Future derived secrets already exposed; contains the indices of the exposed validator
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# at RANDAO reveal period % EARLY_DERIVED_SECRET_PENALTY_MAX_FUTURE_EPOCHS
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exposed_derived_secrets: Vector[List[ValidatorIndex, PLACEHOLDER],
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EARLY_DERIVED_SECRET_PENALTY_MAX_FUTURE_EPOCHS]
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```
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## Helper functions
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### Crypto
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#### `bls_verify_multiple`
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`bls_verify_multiple` is a function for verifying a BLS signature constructed from multiple messages, as defined in the [BLS Signature spec](../bls_signature.md#bls_verify_multiple).
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### Misc
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#### `pack_compact_validator`
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```python
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def pack_compact_validator(index: int, slashed: bool, balance_in_increments: int) -> int:
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@ -212,7 +274,7 @@ def pack_compact_validator(index: int, slashed: bool, balance_in_increments: int
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return (index << 16) + (slashed << 15) + balance_in_increments
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```
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### `committee_to_compact_committee`
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#### `committee_to_compact_committee`
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```python
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def committee_to_compact_committee(state: BeaconState, committee: Sequence[ValidatorIndex]) -> CompactCommittee:
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@ -228,7 +290,24 @@ def committee_to_compact_committee(state: BeaconState, committee: Sequence[Valid
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return CompactCommittee(pubkeys=pubkeys, compact_validators=compact_validators)
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```
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### `get_shard_committee`
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#### `chunks_to_body_root`
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```python
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def chunks_to_body_root(chunks):
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return hash_tree_root(chunks + [EMPTY_CHUNK_ROOT] * (MAX_SHARD_BLOCK_CHUNKS - len(chunks)))
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```
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### Beacon state accessors
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#### `get_online_validators`
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```python
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def get_online_indices(state: BeaconState) -> Set[ValidatorIndex]:
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active_validators = get_active_validator_indices(state, get_current_epoch(state))
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return set([i for i in active_validators if state.online_countdown[i] != 0])
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```
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#### `get_shard_committee`
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```python
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def get_shard_committee(beacon_state: BeaconState, epoch: Epoch, shard: Shard) -> Sequence[ValidatorIndex]:
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@ -240,7 +319,7 @@ def get_shard_committee(beacon_state: BeaconState, epoch: Epoch, shard: Shard) -
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return compute_committee(active_validator_indices, seed, 0, ACTIVE_SHARDS)
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```
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### `get_shard_proposer_index`
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#### `get_shard_proposer_index`
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```python
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def get_shard_proposer_index(beacon_state: BeaconState, slot: Slot, shard: Shard) -> ValidatorIndex:
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@ -249,7 +328,7 @@ def get_shard_proposer_index(beacon_state: BeaconState, slot: Slot, shard: Shard
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return committee[r % len(committee)]
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```
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### `get_light_client_committee`
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#### `get_light_client_committee`
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```python
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def get_light_client_committee(beacon_state: BeaconState, epoch: Epoch) -> Sequence[ValidatorIndex]:
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@ -261,7 +340,7 @@ def get_light_client_committee(beacon_state: BeaconState, epoch: Epoch) -> Seque
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return compute_committee(active_validator_indices, seed, 0, ACTIVE_SHARDS)[:TARGET_COMMITTEE_SIZE]
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```
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### `get_indexed_attestation`
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#### `get_indexed_attestation`
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```python
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def get_indexed_attestation(beacon_state: BeaconState, attestation: Attestation) -> AttestationAndCommittee:
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@ -269,7 +348,7 @@ def get_indexed_attestation(beacon_state: BeaconState, attestation: Attestation)
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return AttestationAndCommittee(committee, attestation)
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```
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### `get_updated_gasprice`
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#### `get_updated_gasprice`
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```python
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def get_updated_gasprice(prev_gasprice: Gwei, length: uint8) -> Gwei:
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@ -281,7 +360,24 @@ def get_updated_gasprice(prev_gasprice: Gwei, length: uint8) -> Gwei:
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return max(prev_gasprice, MIN_GASPRICE + delta) - delta
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```
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### `is_valid_indexed_attestation`
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#### `get_shard`
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```python
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def get_shard(state: BeaconState, attestation: Attestation) -> Shard:
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return Shard((attestation.data.index + get_start_shard(state, attestation.data.slot)) % ACTIVE_SHARDS)
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```
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#### `get_offset_slots`
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```python
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def get_offset_slots(state: BeaconState, start_slot: Slot) -> Sequence[Slot]:
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return [start_slot + x for x in SHARD_BLOCK_OFFSETS if start_slot + x < state.slot]
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```
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### Predicates
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#### `is_valid_indexed_attestation`
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```python
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def is_valid_indexed_attestation(state: BeaconState, indexed_attestation: AttestationAndCommittee) -> bool:
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@ -314,49 +410,46 @@ def is_valid_indexed_attestation(state: BeaconState, indexed_attestation: Attest
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)
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```
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### `get_shard`
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### Block processing
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```python
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def get_shard(state: BeaconState, attestation: Attestation) -> Shard:
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return Shard((attestation.data.index + get_start_shard(state, data.slot)) % ACTIVE_SHARDS)
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def process_block(state: BeaconState, block: BeaconBlock) -> None:
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process_block_header(state, block)
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process_randao(state, block.body)
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process_eth1_data(state, block.body)
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verify_shard_transition_false_positives(state, block)
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process_light_client_signatures(state, block)
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process_operations(state, block.body)
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```
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### `get_offset_slots`
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#### Operations
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```python
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def get_offset_slots(state: BeaconState, start_slot: Slot) -> Sequence[Slot]:
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return [start_slot + x for x in SHARD_BLOCK_OFFSETS if start_slot + x < state.slot]
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def process_operations(state: BeaconState, body: BeaconBlockBody) -> None:
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# Verify that outstanding deposits are processed up to the maximum number of deposits
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assert len(body.deposits) == min(MAX_DEPOSITS, state.eth1_data.deposit_count - state.eth1_deposit_index)
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def process_operations(operations, fn):
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for operation in operations:
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fn(state, operation)
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process_operations(body.proposer_slashings, process_proposer_slashing)
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process_operations(body.attester_slashings, process_attester_slashing)
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# New attestation processing
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process_attestations(state, block, body.attestations)
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process_operations(body.deposits, process_deposit)
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process_operations(body.voluntary_exits, process_voluntary_exit)
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# TODO process_operations(body.shard_receipt_proofs, process_shard_receipt_proofs)
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```
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### `chunks_to_body_root`
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##### New Attestation processing
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```python
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def chunks_to_body_root(chunks):
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return hash_tree_root(chunks + [EMPTY_CHUNK_ROOT] * (MAX_SHARD_BLOCK_CHUNKS - len(chunks)))
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```
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## Beacon Chain Changes
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### New beacon state fields
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```python
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shard_states: Vector[ShardState, MAX_SHARDS]
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online_countdown: Bytes[VALIDATOR_REGISTRY_LIMIT]
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current_light_committee: CompactCommittee
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next_light_committee: CompactCommittee
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```
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### New beacon block data fields
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```python
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shard_transitions: Vector[ShardTransition, MAX_SHARDS]
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light_client_signature_bitfield: Bitlist[LIGHT_CLIENT_COMMITTEE_SIZE]
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light_client_signature: BLSSignature
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```
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### Attestation processing
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|
||||
#### `validate_attestation`
|
||||
###### `validate_attestation`
|
||||
|
||||
```python
|
||||
def validate_attestation(state: BeaconState, attestation: Attestation) -> None:
|
||||
|
|
@ -381,7 +474,7 @@ def validate_attestation(state: BeaconState, attestation: Attestation) -> None:
|
|||
assert data.shard_transition_root == Hash()
|
||||
```
|
||||
|
||||
#### `apply_shard_transition`
|
||||
###### `apply_shard_transition`
|
||||
|
||||
```python
|
||||
def apply_shard_transition(state: BeaconState, shard: Shard, transition: ShardTransition) -> None:
|
||||
|
|
@ -430,7 +523,7 @@ def apply_shard_transition(state: BeaconState, shard: Shard, transition: ShardTr
|
|||
state.shard_states[shard].slot = state.slot - 1
|
||||
```
|
||||
|
||||
#### `process_attestations`
|
||||
###### `process_attestations`
|
||||
|
||||
```python
|
||||
def process_attestations(state: BeaconState, block: BeaconBlock, attestations: Sequence[Attestation]) -> None:
|
||||
|
|
@ -490,7 +583,7 @@ def process_attestations(state: BeaconState, block: BeaconBlock, attestations: S
|
|||
state.previous_epoch_attestations.append(pending_attestation)
|
||||
```
|
||||
|
||||
### Misc block post-processing
|
||||
#### Shard transition false positives
|
||||
|
||||
```python
|
||||
def verify_shard_transition_false_positives(state: BeaconState, block: BeaconBlock) -> None:
|
||||
|
|
@ -500,7 +593,7 @@ def verify_shard_transition_false_positives(state: BeaconState, block: BeaconBlo
|
|||
assert block.shard_transition[shard] == ShardTransition()
|
||||
```
|
||||
|
||||
### Light client processing
|
||||
#### Light client processing
|
||||
|
||||
```python
|
||||
def process_light_client_signatures(state: BeaconState, block: BeaconBlock) -> None:
|
||||
|
|
@ -524,10 +617,23 @@ def process_light_client_signatures(state: BeaconState, block: BeaconBlock) -> N
|
|||
)
|
||||
```
|
||||
|
||||
|
||||
### Epoch transition
|
||||
|
||||
This epoch transition overrides the phase0 epoch transition:
|
||||
|
||||
```python
|
||||
def phase_1_epoch_transition(state: BeaconState) -> None:
|
||||
def process_epoch(state: BeaconState) -> None:
|
||||
process_justification_and_finalization(state)
|
||||
process_rewards_and_penalties(state)
|
||||
process_registry_updates(state)
|
||||
# TODO process_reveal_deadlines
|
||||
# TODO process_challenge_deadlines
|
||||
process_slashings(state)
|
||||
# TODO update_period_committee
|
||||
process_final_updates(state)
|
||||
# TODO process_custody_final_updates
|
||||
|
||||
# Slowly remove validators from the "online" set if they do not show up
|
||||
for index in range(len(state.validators)):
|
||||
if state.online_countdown[index] != 0:
|
||||
|
|
@ -544,40 +650,3 @@ def phase_1_epoch_transition(state: BeaconState) -> None:
|
|||
for index in get_attesting_indices(state, pending_attestation.data, pending_attestation.aggregation_bits):
|
||||
state.online_countdown[index] = ONLINE_PERIOD
|
||||
```
|
||||
|
||||
## Fraud proofs
|
||||
|
||||
TODO. The intent is to have a single universal fraud proof type, which contains the following parts:
|
||||
|
||||
1. An on-time attestation on some `shard` signing a `ShardTransition`
|
||||
2. An index `i` of a particular position to focus on
|
||||
3. The `ShardTransition` itself
|
||||
4. The full body of the block
|
||||
5. A Merkle proof to the `shard_states` in the parent block the attestation is referencing
|
||||
|
||||
The proof verifies that one of the two conditions is false:
|
||||
|
||||
1. `custody_bits[i][j] != generate_custody_bit(subkey, block_contents)` for any `j`
|
||||
2. `execute_state_transition(shard, slot, transition.shard_states[i-1].data, hash_tree_root(parent), get_shard_proposer_index(state, shard, slot), block_contents) != transition.shard_states[i].data` (if `i=0` then instead use `parent.shard_states[shard][-1].data`)
|
||||
|
||||
## Shard state transition function
|
||||
|
||||
```python
|
||||
def shard_state_transition(shard: Shard, slot: Slot, pre_state: Hash, previous_beacon_root: Hash, proposer_pubkey: BLSPubkey, block_data: BytesN[MAX_SHARD_BLOCK_CHUNKS * SHARD_BLOCK_CHUNK_SIZE]) -> Hash:
|
||||
# We will add something more substantive in phase 2
|
||||
return hash(pre_state + hash_tree_root(previous_beacon_root) + hash_tree_root(block_data))
|
||||
```
|
||||
|
||||
## Honest committee member behavior
|
||||
|
||||
Suppose you are a committee member on shard `shard` at slot `current_slot`. Let `state` be the head beacon state you are building on, and let `QUARTER_PERIOD = SECONDS_PER_SLOT // 4`. `2 * QUARTER_PERIOD` seconds into slot `slot`, run the following procedure:
|
||||
|
||||
* Initialize `proposals = []`, `shard_states = []`, `shard_state = state.shard_states[shard][-1]`, `start_slot = shard_state.slot`.
|
||||
* For `slot in get_offset_slots(state, start_slot)`, do the following:
|
||||
* Look for all valid proposals for `slot`; that is, a Bytes `proposal` where `shard_state_transition(shard, slot, shard_state, get_block_root_at_slot(state, state.slot - 1), get_shard_proposer_index(state, shard, slot), proposal)` returns a result and does not throw an exception. Let `choices` be the set of non-empty valid proposals you discover.
|
||||
* If `len(choices) == 0`, do `proposals.append(make_empty_proposal(shard_state, slot))`
|
||||
* If `len(choices) == 1`, do `proposals.append(choices[0])`
|
||||
* If `len(choices) > 1`, let `winning_proposal` be the proposal with the largest number of total attestations from slots in `state.shard_next_slots[shard]....slot-1` supporting it or any of its descendants, breaking ties by choosing the first proposal locally seen. Do `proposals.append(winning_proposal)`.
|
||||
* If `proposals[-1]` is NOT an empty proposal, set `shard_state = shard_state_transition(shard, slot, shard_state, get_block_root_at_slot(state, state.slot - 1), get_shard_proposer_index(state, shard, slot), proposals[-1])` and do `shard_states.append(shard_state)`. If it is an empty proposal, leave `shard_state` unchanged.
|
||||
|
||||
Make an attestation using `shard_data_roots = [hash_tree_root(proposal) for proposal in proposals]` and `shard_state_roots = shard_states`.
|
||||
|
|
@ -231,45 +231,6 @@ class EarlyDerivedSecretReveal(Container):
|
|||
mask: Bytes32
|
||||
```
|
||||
|
||||
### Phase 0 container updates
|
||||
|
||||
Add the following fields to the end of the specified container objects. Fields with underlying type `uint64` are initialized to `0` and list fields are initialized to `[]`.
|
||||
|
||||
#### `Validator`
|
||||
|
||||
```python
|
||||
class Validator(Container):
|
||||
# next_custody_secret_to_reveal is initialised to the custody period
|
||||
# (of the particular validator) in which the validator is activated
|
||||
# = get_custody_period_for_validator(...)
|
||||
next_custody_secret_to_reveal: uint64
|
||||
max_reveal_lateness: Epoch
|
||||
```
|
||||
|
||||
#### `BeaconState`
|
||||
|
||||
```python
|
||||
class BeaconState(Container):
|
||||
custody_chunk_challenge_records: List[CustodyChunkChallengeRecord, PLACEHOLDER]
|
||||
custody_bit_challenge_records: List[CustodyBitChallengeRecord, PLACEHOLDER]
|
||||
custody_challenge_index: uint64
|
||||
|
||||
# Future derived secrets already exposed; contains the indices of the exposed validator
|
||||
# at RANDAO reveal period % EARLY_DERIVED_SECRET_PENALTY_MAX_FUTURE_EPOCHS
|
||||
exposed_derived_secrets: Vector[List[ValidatorIndex, PLACEHOLDER],
|
||||
EARLY_DERIVED_SECRET_PENALTY_MAX_FUTURE_EPOCHS]
|
||||
```
|
||||
|
||||
#### `BeaconBlockBody`
|
||||
|
||||
```python
|
||||
class BeaconBlockBody(Container):
|
||||
custody_chunk_challenges: List[CustodyChunkChallenge, PLACEHOLDER]
|
||||
custody_bit_challenges: List[CustodyBitChallenge, PLACEHOLDER]
|
||||
custody_responses: List[CustodyResponse, PLACEHOLDER]
|
||||
custody_key_reveals: List[CustodyKeyReveal, PLACEHOLDER]
|
||||
early_derived_secret_reveals: List[EarlyDerivedSecretReveal, PLACEHOLDER]
|
||||
```
|
||||
|
||||
## Helpers
|
||||
|
||||
|
|
@ -732,12 +693,9 @@ def process_bit_challenge_response(state: BeaconState,
|
|||
|
||||
### Handling of custody-related deadlines
|
||||
|
||||
Run `process_reveal_deadlines(state)` immediately after `process_registry_updates(state)`:
|
||||
Run `process_reveal_deadlines(state)` after `process_registry_updates(state)`:
|
||||
|
||||
```python
|
||||
# begin insert @process_reveal_deadlines
|
||||
process_reveal_deadlines(state)
|
||||
# end insert @process_reveal_deadlines
|
||||
def process_reveal_deadlines(state: BeaconState) -> None:
|
||||
for index, validator in enumerate(state.validators):
|
||||
deadline = validator.next_custody_secret_to_reveal + (CUSTODY_RESPONSE_DEADLINE // EPOCHS_PER_CUSTODY_PERIOD)
|
||||
|
|
@ -748,9 +706,6 @@ def process_reveal_deadlines(state: BeaconState) -> None:
|
|||
Run `process_challenge_deadlines(state)` immediately after `process_reveal_deadlines(state)`:
|
||||
|
||||
```python
|
||||
# begin insert @process_challenge_deadlines
|
||||
process_challenge_deadlines(state)
|
||||
# end insert @process_challenge_deadlines
|
||||
def process_challenge_deadlines(state: BeaconState) -> None:
|
||||
for custody_chunk_challenge in state.custody_chunk_challenge_records:
|
||||
if get_current_epoch(state) > custody_chunk_challenge.inclusion_epoch + CUSTODY_RESPONSE_DEADLINE:
|
||||
|
|
@ -765,13 +720,10 @@ def process_challenge_deadlines(state: BeaconState) -> None:
|
|||
records[records.index(custody_bit_challenge)] = CustodyBitChallengeRecord()
|
||||
```
|
||||
|
||||
Append this to `process_final_updates(state)`:
|
||||
After `process_final_updates(state)`, additional updates are made for the custody game:
|
||||
|
||||
```python
|
||||
# begin insert @after_process_final_updates
|
||||
after_process_final_updates(state)
|
||||
# end insert @after_process_final_updates
|
||||
def after_process_final_updates(state: BeaconState) -> None:
|
||||
def process_custody_final_updates(state: BeaconState) -> None:
|
||||
current_epoch = get_current_epoch(state)
|
||||
# Clean up exposed RANDAO key reveals
|
||||
state.exposed_derived_secrets[current_epoch % EARLY_DERIVED_SECRET_PENALTY_MAX_FUTURE_EPOCHS] = []
|
||||
|
|
|
|||
|
|
@ -0,0 +1,52 @@
|
|||
# Ethereum 2.0 Phase 1 -- Crosslinks and Shard Data
|
||||
|
||||
**Notice**: This document is a work-in-progress for researchers and implementers.
|
||||
|
||||
## Table of contents
|
||||
|
||||
<!-- TOC -->
|
||||
|
||||
TODO
|
||||
|
||||
<!-- /TOC -->
|
||||
|
||||
## Introduction
|
||||
|
||||
This document describes the shard transition function (data layer only) and the shard fork choice rule as part of Phase 1 of Ethereum 2.0.
|
||||
|
||||
## Fraud proofs
|
||||
|
||||
TODO. The intent is to have a single universal fraud proof type, which contains the following parts:
|
||||
|
||||
1. An on-time attestation on some `shard` signing a `ShardTransition`
|
||||
2. An index `i` of a particular position to focus on
|
||||
3. The `ShardTransition` itself
|
||||
4. The full body of the block
|
||||
5. A Merkle proof to the `shard_states` in the parent block the attestation is referencing
|
||||
|
||||
The proof verifies that one of the two conditions is false:
|
||||
|
||||
1. `custody_bits[i][j] != generate_custody_bit(subkey, block_contents)` for any `j`
|
||||
2. `execute_state_transition(shard, slot, transition.shard_states[i-1].data, hash_tree_root(parent), get_shard_proposer_index(state, shard, slot), block_contents) != transition.shard_states[i].data` (if `i=0` then instead use `parent.shard_states[shard][-1].data`)
|
||||
|
||||
## Shard state transition function
|
||||
|
||||
```python
|
||||
def shard_state_transition(shard: Shard, slot: Slot, pre_state: Hash, previous_beacon_root: Hash, proposer_pubkey: BLSPubkey, block_data: BytesN[MAX_SHARD_BLOCK_CHUNKS * SHARD_BLOCK_CHUNK_SIZE]) -> Hash:
|
||||
# We will add something more substantive in phase 2
|
||||
return hash(pre_state + hash_tree_root(previous_beacon_root) + hash_tree_root(block_data))
|
||||
```
|
||||
|
||||
## Honest committee member behavior
|
||||
|
||||
Suppose you are a committee member on shard `shard` at slot `current_slot`. Let `state` be the head beacon state you are building on, and let `QUARTER_PERIOD = SECONDS_PER_SLOT // 4`. `2 * QUARTER_PERIOD` seconds into slot `slot`, run the following procedure:
|
||||
|
||||
* Initialize `proposals = []`, `shard_states = []`, `shard_state = state.shard_states[shard][-1]`, `start_slot = shard_state.slot`.
|
||||
* For `slot in get_offset_slots(state, start_slot)`, do the following:
|
||||
* Look for all valid proposals for `slot`; that is, a Bytes `proposal` where `shard_state_transition(shard, slot, shard_state, get_block_root_at_slot(state, state.slot - 1), get_shard_proposer_index(state, shard, slot), proposal)` returns a result and does not throw an exception. Let `choices` be the set of non-empty valid proposals you discover.
|
||||
* If `len(choices) == 0`, do `proposals.append(make_empty_proposal(shard_state, slot))`
|
||||
* If `len(choices) == 1`, do `proposals.append(choices[0])`
|
||||
* If `len(choices) > 1`, let `winning_proposal` be the proposal with the largest number of total attestations from slots in `state.shard_next_slots[shard]....slot-1` supporting it or any of its descendants, breaking ties by choosing the first proposal locally seen. Do `proposals.append(winning_proposal)`.
|
||||
* If `proposals[-1]` is NOT an empty proposal, set `shard_state = shard_state_transition(shard, slot, shard_state, get_block_root_at_slot(state, state.slot - 1), get_shard_proposer_index(state, shard, slot), proposals[-1])` and do `shard_states.append(shard_state)`. If it is an empty proposal, leave `shard_state` unchanged.
|
||||
|
||||
Make an attestation using `shard_data_roots = [hash_tree_root(proposal) for proposal in proposals]` and `shard_state_roots = shard_states`.
|
||||
Loading…
Reference in New Issue