From ba8c44dd9abfe10f671fb556056e76e88a5946fb Mon Sep 17 00:00:00 2001 From: Hsiao-Wei Wang Date: Sat, 19 Jan 2019 15:46:09 +0800 Subject: [PATCH 01/70] Fix the new `Eth1Data` fields to `bytes32` --- specs/core/0_beacon-chain.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 0394761ad..3ef3c94e2 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -601,9 +601,9 @@ Unless otherwise indicated, code appearing in `this style` is to be interpreted ```python { # Root of the deposit tree - 'deposit_root': 'hash32', + 'deposit_root': 'bytes32', # Block hash - 'block_hash': 'hash32', + 'block_hash': 'bytes32', } ``` From 41813462c3e3b6af6239fea622cdebccd3761c5c Mon Sep 17 00:00:00 2001 From: Hsiao-Wei Wang Date: Sat, 19 Jan 2019 15:58:24 +0800 Subject: [PATCH 02/70] Add custom types --- specs/core/0_beacon-chain.md | 59 +++++++++++++++++++++++------------- 1 file changed, 38 insertions(+), 21 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 3ef3c94e2..569296b5f 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -50,6 +50,7 @@ - [`ValidatorRegistryDeltaBlock`](#validatorregistrydeltablock) - [`Eth1Data`](#eth1data) - [`Eth1DataVote`](#eth1datavote) + - [Custom Types](#custom-types) - [Ethereum 1.0 deposit contract](#ethereum-10-deposit-contract) - [Deposit arguments](#deposit-arguments) - [Withdrawal credentials](#withdrawal-credentials) @@ -253,6 +254,8 @@ Unless otherwise indicated, code appearing in `this style` is to be interpreted ## Data structures +The following data structures are [SimpleSerialize (SSZ)](https://github.com/ethereum/eth2.0-specs/blob/master/specs/simple-serialize.md) objects. + ### Beacon chain operations #### Proposer slashings @@ -618,6 +621,20 @@ Unless otherwise indicated, code appearing in `this style` is to be interpreted } ``` +## Custom Types + +We define the following Python custom types for type hinting and readability: + +| Name | Type | Description | +| - | - | - | +| `SlotNumber` | unsigned 64-bit integer | the number of a slot | +| `ShardNumber` | unsigned 64-bit integer | the number of a shard | +| `ValidatorIndex` | unsigned 24-bit integer | the index number of validator in the registry | +| `Gwei` | unsigned 64-bit integer | the amount in Gwei | +| `Bytes32` | 32-byte data | the binary data in 32-byte length | +| `BLSPubkey` | 48-byte data | the public key in BLS signature scheme | +| `BLSSignature` | 96-byte data | the signature in BLS signature scheme | + ## Ethereum 1.0 deposit contract The initial deployment phases of Ethereum 2.0 are implemented without consensus changes to Ethereum 1.0. A deposit contract at address `DEPOSIT_CONTRACT_ADDRESS` is added to Ethereum 1.0 for deposits of ETH to the beacon chain. Validator balances will be withdrawable to the shards in phase 2, i.e. when the EVM2.0 is deployed and the shards have state. @@ -788,7 +805,7 @@ Note: We aim to migrate to a S[T/N]ARK-friendly hash function in a future Ethere #### `is_active_validator` ```python -def is_active_validator(validator: Validator, slot: int) -> bool: +def is_active_validator(validator: Validator, slot: SlotNumber) -> bool: """ Checks if ``validator`` is active. """ @@ -798,7 +815,7 @@ def is_active_validator(validator: Validator, slot: int) -> bool: #### `get_active_validator_indices` ```python -def get_active_validator_indices(validators: [Validator], slot: int) -> List[int]: +def get_active_validator_indices(validators: [Validator], slot: SlotNumber) -> List[ValidatorIndex]: """ Gets indices of active validators from ``validators``. """ @@ -890,7 +907,7 @@ def get_committee_count_per_slot(active_validator_count: int) -> int: ```python def get_shuffling(seed: Bytes32, validators: List[Validator], - slot: int) -> List[List[int]] + slot: SlotNumber) -> List[List[ValidatorIndex]] """ Shuffles ``validators`` into crosslink committees seeded by ``seed`` and ``slot``. Returns a list of ``EPOCH_LENGTH * committees_per_slot`` committees where each @@ -942,7 +959,7 @@ def get_current_epoch_committee_count_per_slot(state: BeaconState) -> int: ```python def get_crosslink_committees_at_slot(state: BeaconState, - slot: int) -> List[Tuple[List[int], int]]: + slot: SlotNumber) -> List[Tuple[List[ValidatorIndex], ShardNumber]]: """ Returns the list of ``(committee, shard)`` tuples for the ``slot``. """ @@ -983,7 +1000,7 @@ def get_crosslink_committees_at_slot(state: BeaconState, ```python def get_block_root(state: BeaconState, - slot: int) -> Bytes32: + slot: SlotNumber) -> Bytes32: """ Returns the block root at a recent ``slot``. """ @@ -998,7 +1015,7 @@ def get_block_root(state: BeaconState, ```python def get_randao_mix(state: BeaconState, - slot: int) -> Bytes32: + slot: SlotNumber) -> Bytes32: """ Returns the randao mix at a recent ``slot``. """ @@ -1011,7 +1028,7 @@ def get_randao_mix(state: BeaconState, ```python def get_beacon_proposer_index(state: BeaconState, - slot: int) -> int: + slot: SlotNumber) -> ValidatorIndex: """ Returns the beacon proposer index for the ``slot``. """ @@ -1037,7 +1054,7 @@ def merkle_root(values: List[Bytes32]) -> Bytes32: ```python def get_attestation_participants(state: BeaconState, attestation_data: AttestationData, - aggregation_bitfield: bytes) -> List[int]: + aggregation_bitfield: bytes) -> List[ValidatorIndex]: """ Returns the participant indices at for the ``attestation_data`` and ``aggregation_bitfield``. """ @@ -1065,7 +1082,7 @@ def get_attestation_participants(state: BeaconState, #### `get_effective_balance` ```python -def get_effective_balance(state: State, index: int) -> int: +def get_effective_balance(state: State, index: ValidatorIndex) -> Gwei: """ Returns the effective balance (also known as "balance at stake") for a ``validator`` with the given ``index``. """ @@ -1076,7 +1093,7 @@ def get_effective_balance(state: State, index: int) -> int: ```python def get_fork_version(fork: Fork, - slot: int) -> int: + slot: SlotNumber) -> int: if slot < fork.slot: return fork.previous_version else: @@ -1087,7 +1104,7 @@ def get_fork_version(fork: Fork, ```python def get_domain(fork: Fork, - slot: int, + slot: SlotNumber, domain_type: int) -> int: return get_fork_version( fork, @@ -1294,8 +1311,8 @@ First, a helper function: ```python def validate_proof_of_possession(state: BeaconState, - pubkey: Bytes48, - proof_of_possession: Bytes96, + pubkey: BLSPubkey, + proof_of_possession: BLSSignature, withdrawal_credentials: Bytes32, randao_commitment: Bytes32, custody_commitment: Bytes32) -> bool: @@ -1323,9 +1340,9 @@ Now, to add a [validator](#dfn-validator) or top up an existing [validator](#dfn ```python def process_deposit(state: BeaconState, - pubkey: Bytes48, - amount: int, - proof_of_possession: Bytes96, + pubkey: BLSPubkey, + amount: Gwei, + proof_of_possession: BLSSignature, withdrawal_credentials: Bytes32, randao_commitment: Bytes32, custody_commitment: Bytes32) -> None: @@ -1379,7 +1396,7 @@ def process_deposit(state: BeaconState, Note: All functions in this section mutate `state`. ```python -def activate_validator(state: BeaconState, index: int, genesis: bool) -> None: +def activate_validator(state: BeaconState, index: ValidatorIndex, genesis: bool) -> None: validator = state.validator_registry[index] validator.activation_slot = GENESIS_SLOT if genesis else (state.slot + ENTRY_EXIT_DELAY) @@ -1395,13 +1412,13 @@ def activate_validator(state: BeaconState, index: int, genesis: bool) -> None: ``` ```python -def initiate_validator_exit(state: BeaconState, index: int) -> None: +def initiate_validator_exit(state: BeaconState, index: ValidatorIndex) -> None: validator = state.validator_registry[index] validator.status_flags |= INITIATED_EXIT ``` ```python -def exit_validator(state: BeaconState, index: int) -> None: +def exit_validator(state: BeaconState, index: ValidatorIndex) -> None: validator = state.validator_registry[index] # The following updates only occur if not previous exited @@ -1424,7 +1441,7 @@ def exit_validator(state: BeaconState, index: int) -> None: ``` ```python -def penalize_validator(state: BeaconState, index: int) -> None: +def penalize_validator(state: BeaconState, index: ValidatorIndex) -> None: exit_validator(state, index) validator = state.validator_registry[index] state.latest_penalized_balances[(state.slot // EPOCH_LENGTH) % LATEST_PENALIZED_EXIT_LENGTH] += get_effective_balance(state, index) @@ -1437,7 +1454,7 @@ def penalize_validator(state: BeaconState, index: int) -> None: ``` ```python -def prepare_validator_for_withdrawal(state: BeaconState, index: int) -> None: +def prepare_validator_for_withdrawal(state: BeaconState, index: ValidatorIndex) -> None: validator = state.validator_registry[index] validator.status_flags |= WITHDRAWABLE ``` From 1ae3768ac868b23449ac79bd57edec9bad1f804c Mon Sep 17 00:00:00 2001 From: Hsiao-Wei Wang Date: Sat, 19 Jan 2019 16:06:00 +0800 Subject: [PATCH 03/70] Minor fixes --- specs/core/0_beacon-chain.md | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 569296b5f..60b39c70b 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -254,7 +254,7 @@ Unless otherwise indicated, code appearing in `this style` is to be interpreted ## Data structures -The following data structures are [SimpleSerialize (SSZ)](https://github.com/ethereum/eth2.0-specs/blob/master/specs/simple-serialize.md) objects. +The following data structures are defined as [SimpleSerialize (SSZ)](https://github.com/ethereum/eth2.0-specs/blob/master/specs/simple-serialize.md) objects. ### Beacon chain operations @@ -801,7 +801,7 @@ Note: We aim to migrate to a S[T/N]ARK-friendly hash function in a future Ethere #### `hash_tree_root` -`hash_tree_root` is a function for hashing objects into a single root utilizing a hash tree structure. `hash_tree_root` is defined in the [SimpleSerialize spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/simple-serialize.md#tree-hash). +`def hash_tree_root(object: SSZSerializable) -> Bytes32` is a function for hashing objects into a single root utilizing a hash tree structure. `hash_tree_root` is defined in the [SimpleSerialize spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/simple-serialize.md#tree-hash). #### `is_active_validator` ```python @@ -815,7 +815,7 @@ def is_active_validator(validator: Validator, slot: SlotNumber) -> bool: #### `get_active_validator_indices` ```python -def get_active_validator_indices(validators: [Validator], slot: SlotNumber) -> List[ValidatorIndex]: +def get_active_validator_indices(validators: List[Validator], slot: SlotNumber) -> List[ValidatorIndex]: """ Gets indices of active validators from ``validators``. """ @@ -1568,7 +1568,7 @@ For each `deposit` in `block.body.deposits`: * Verify that `verify_merkle_branch(hash(serialized_deposit_data), deposit.branch, DEPOSIT_CONTRACT_TREE_DEPTH, deposit.index, state.latest_eth1_data.deposit_root)` is `True`. ```python -def verify_merkle_branch(leaf: Bytes32, branch: [Bytes32], depth: int, index: int, root: Bytes32) -> bool: +def verify_merkle_branch(leaf: Bytes32, branch: List[Bytes32], depth: int, index: int, root: Bytes32) -> bool: value = leaf for i in range(depth): if index // (2**i) % 2: From a5519a7d3b5c0b675026a2daef9477f06ae795a6 Mon Sep 17 00:00:00 2001 From: Jannik Luhn Date: Tue, 22 Jan 2019 17:14:25 +0100 Subject: [PATCH 04/70] SSZ: List serialization with variable element size Fix #232 --- specs/simple-serialize.md | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/specs/simple-serialize.md b/specs/simple-serialize.md index 8630c47c6..cca2969e6 100644 --- a/specs/simple-serialize.md +++ b/specs/simple-serialize.md @@ -143,9 +143,9 @@ Lists are a collection of elements of the same homogeneous type. | Length of serialized list fits into 4 bytes | ``len(serialized) < 2**32`` | -1. Get the number of raw bytes to serialize: it is ``len(list) * sizeof(element)``. - * Encode that as a `4-byte` **little endian** `uint32`. -2. Append the elements in a packed manner. +1. Serialize all list elements individually and concatenate them. + +2. Prefix the concatenation with its length encoded as a `4-byte` **little-endian** unsigned integer. * *Note on efficiency*: consider using a container that does not need to iterate over all elements to get its length. For example Python lists, C++ vectors or Rust Vec. From f8670e80692c02a1de4be41bdf9b9ca94948419f Mon Sep 17 00:00:00 2001 From: Jannik Luhn Date: Tue, 22 Jan 2019 17:16:37 +0100 Subject: [PATCH 05/70] SSZ: Remove note on efficiency --- specs/simple-serialize.md | 2 -- 1 file changed, 2 deletions(-) diff --git a/specs/simple-serialize.md b/specs/simple-serialize.md index cca2969e6..eff65f49e 100644 --- a/specs/simple-serialize.md +++ b/specs/simple-serialize.md @@ -147,8 +147,6 @@ Lists are a collection of elements of the same homogeneous type. 2. Prefix the concatenation with its length encoded as a `4-byte` **little-endian** unsigned integer. -* *Note on efficiency*: consider using a container that does not need to iterate over all elements to get its length. For example Python lists, C++ vectors or Rust Vec. - **Example in Python** ```python From 6c824ffee462686787b27cb7ad11420513eccb32 Mon Sep 17 00:00:00 2001 From: Justin Date: Tue, 22 Jan 2019 20:45:30 +0000 Subject: [PATCH 06/70] Remove placeholders MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Remove all custody and VDF placeholders (56 lines less!). A few notes on the placeholder fields and logic: * All placeholder fields were dummy fields that can easily be restored in the phase 1 hard fork. * One special case to the above is `custody_bit_0_validator_indices` in `SlashableVoteData` which was renamed to `validator_indices`. Renaming it back is *not* a spec change because SSZ field names are [no longer part of the spec](https://github.com/ethereum/eth2.0-specs/commit/a9328157a87451ee4f372df272ece158b386ec41#diff-8d8fe480a35579c7be2f976d9b321216). * The placeholder logic was written using generalised functions (e.g. `bls_verify_multiple` vs `bls_verify`, and `indices(slashable_vote_data)` vs `slashable_vote_data.validator_indices`). This generality was unnecessary because it was not triggered when all custody bits were 0. This means we can simplify the logic without being inconsistent with phase 1. Rationale: * Keep phase 0 (likely far harder to deliver than phase 1) as clean as possible * Focus on upgrade paths and incremental releases * Custody is still under research—keep the design space open --- specs/core/0_beacon-chain.md | 76 +++++------------------------------- 1 file changed, 10 insertions(+), 66 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 56430cd56..a47cad399 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -30,7 +30,6 @@ - [Attestations](#attestations) - [`Attestation`](#attestation) - [`AttestationData`](#attestationdata) - - [`AttestationDataAndCustodyBit`](#attestationdataandcustodybit) - [Deposits](#deposits) - [`Deposit`](#deposit) - [`DepositData`](#depositdata) @@ -104,7 +103,6 @@ - [Attestations](#attestations-1) - [Deposits](#deposits-1) - [Exits](#exits-1) - - [Custody](#custody) - [Per-epoch processing](#per-epoch-processing) - [Helpers](#helpers) - [Eth1 data](#eth1-data-1) @@ -292,10 +290,8 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be ```python { - # Validator indices with custody bit equal to 0 - 'custody_bit_0_indices': ['uint24'], - # Validator indices with custody bit equal to 1 - 'custody_bit_1_indices': ['uint24'], + # Validator indices + 'validator_indices': ['uint24'], # Attestation data 'data': AttestationData, # Aggregate signature @@ -313,8 +309,6 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'data': AttestationData, # Attester aggregation bitfield 'aggregation_bitfield': 'bytes', - # Custody bitfield - 'custody_bitfield': 'bytes', # BLS aggregate signature 'aggregate_signature': 'bytes96', } @@ -343,17 +337,6 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be } ``` -##### `AttestationDataAndCustodyBit` - -```python -{ - # Attestation data - data: AttestationData, - # Custody bit - custody_bit: bool, -} -``` - #### Deposits ##### `Deposit` @@ -436,16 +419,11 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'proposer_slashings': [ProposerSlashing], 'casper_slashings': [CasperSlashing], 'attestations': [Attestation], - 'custody_reseeds': [CustodyReseed], - 'custody_challenges': [CustodyChallenge], - 'custody_responses': [CustodyResponse], 'deposits': [Deposit], 'exits': [Exit], } ``` -`CustodyReseed`, `CustodyChallenge`, and `CustodyResponse` will be defined in phase 1; for now, put dummy classes as these lists will remain empty throughout phase 0. - #### `ProposalSignedData` ```python @@ -479,7 +457,6 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be # Randomness and committees 'latest_randao_mixes': ['bytes32'], - 'latest_vdf_outputs': ['bytes32'], 'previous_epoch_start_shard': 'uint64', 'current_epoch_start_shard': 'uint64', 'previous_epoch_calculation_slot': 'uint64', @@ -487,9 +464,6 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'previous_epoch_randao_mix': 'bytes32', 'current_epoch_randao_mix': 'bytes32', - # Custody challenges - 'custody_challenges': [CustodyChallenge], - # Finality 'previous_justified_slot': 'uint64', 'justified_slot': 'uint64', @@ -531,10 +505,6 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'exit_count': 'uint64', # Status flags 'status_flags': 'uint64', - # Slot of latest custody reseed - 'latest_custody_reseed_slot': 'uint64', - # Slot of second-latest custody reseed - 'penultimate_custody_reseed_slot': 'uint64', } ``` @@ -557,8 +527,6 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'data': AttestationData, # Attester aggregation bitfield 'aggregation_bitfield': 'bytes', - # Custody bitfield - 'custody_bitfield': 'bytes', # Slot the attestation was included 'slot_included': 'uint64', } @@ -1092,24 +1060,14 @@ def get_domain(fork: Fork, ```python def verify_slashable_vote_data(state: BeaconState, vote_data: SlashableVoteData) -> bool: - if len(vote_data.custody_bit_0_indices) + len(vote_data.custody_bit_1_indices) > MAX_CASPER_VOTES: + if len(vote_data.validator_indices) > MAX_CASPER_VOTES: return False - return bls_verify_multiple( - pubkeys=[ - bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in vote_data.custody_bit_0_indices]), - bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in vote_data.custody_bit_1_indices]), - ], - messages=[ - hash_tree_root(AttestationDataAndCustodyBit(vote_data.data, False)), - hash_tree_root(AttestationDataAndCustodyBit(vote_data.data, True)), - ], + return bls_verify( + pubkey=bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in vote_data.validator_indices]), + message=hash_tree_root(AttestationData(vote_data.data)), signature=vote_data.aggregate_signature, - domain=get_domain( - state.fork, - vote_data.data.slot, - DOMAIN_ATTESTATION, - ), + domain=get_domain(state.fork, vote_data.data.slot, DOMAIN_ATTESTATION), ) ``` @@ -1198,9 +1156,6 @@ A valid block with slot `GENESIS_SLOT` (a "genesis block") has the following val proposer_slashings=[], casper_slashings=[], attestations=[], - custody_reseeds=[], - custody_challenges=[], - custody_responses=[], deposits=[], exits=[], ), @@ -1232,7 +1187,6 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], # Randomness and committees latest_randao_mixes=[ZERO_HASH for _ in range(LATEST_RANDAO_MIXES_LENGTH)], - latest_vdf_outputs=[ZERO_HASH for _ in range(LATEST_RANDAO_MIXES_LENGTH // EPOCH_LENGTH)], previous_epoch_start_shard=GENESIS_START_SHARD, current_epoch_start_shard=GENESIS_START_SHARD, previous_epoch_calculation_slot=GENESIS_SLOT, @@ -1240,9 +1194,6 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], previous_epoch_randao_mix=ZERO_HASH, current_epoch_randao_mix=ZERO_HASH, - # Custody challenges - custody_challenges=[], - # Finality previous_justified_slot=GENESIS_SLOT, justified_slot=GENESIS_SLOT, @@ -1340,8 +1291,6 @@ def process_deposit(state: BeaconState, penalized_slot=FAR_FUTURE_SLOT, exit_count=0, status_flags=0, - latest_custody_reseed_slot=GENESIS_SLOT, - penultimate_custody_reseed_slot=GENESIS_SLOT, ) # Note: In phase 2 registry indices that have been withdrawn for a long time will be recycled. @@ -1489,8 +1438,7 @@ For each `casper_slashing` in `block.body.casper_slashings`: * Let `slashable_vote_data_1 = casper_slashing.slashable_vote_data_1`. * Let `slashable_vote_data_2 = casper_slashing.slashable_vote_data_2`. -* Let `indices(slashable_vote_data) = slashable_vote_data.custody_bit_0_indices + slashable_vote_data.custody_bit_1_indices`. -* Let `intersection = [x for x in indices(slashable_vote_data_1) if x in indices(slashable_vote_data_2)]`. +* Let `intersection = [x for x in slashable_vote_data_1.validator_indices if x in slashable_vote_data_2.validator_indices]`. * Verify that `len(intersection) >= 1`. * Verify that `slashable_vote_data_1.data != slashable_vote_data_2.data`. * Verify that `is_double_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)` or `is_surround_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)`. @@ -1512,9 +1460,9 @@ For each `attestation` in `block.body.attestations`: * `aggregate_signature` verification: * Let `participants = get_attestation_participants(state, attestation.data, attestation.aggregation_bitfield)`. * Let `group_public_key = bls_aggregate_pubkeys([state.validator_registry[v].pubkey for v in participants])`. - * Verify that `bls_verify(pubkey=group_public_key, message=hash_tree_root(AttestationDataAndCustodyBit(attestation.data, False)), signature=attestation.aggregate_signature, domain=get_domain(state.fork, attestation.data.slot, DOMAIN_ATTESTATION))`. + * Verify that `bls_verify(pubkey=group_public_key, message=hash_tree_root(AttestationData(attestation.data)), signature=attestation.aggregate_signature, domain=get_domain(state.fork, attestation.data.slot, DOMAIN_ATTESTATION))`. * [TO BE REMOVED IN PHASE 1] Verify that `attestation.data.shard_block_root == ZERO_HASH`. -* Append `PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, custody_bitfield=attestation.custody_bitfield, slot_included=state.slot)` to `state.latest_attestations`. +* Append `PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, slot_included=state.slot)` to `state.latest_attestations`. #### Deposits @@ -1564,10 +1512,6 @@ For each `exit` in `block.body.exits`: * Verify that `bls_verify(pubkey=validator.pubkey, message=exit_message, signature=exit.signature, domain=get_domain(state.fork, exit.slot, DOMAIN_EXIT))`. * Run `initiate_validator_exit(state, exit.validator_index)`. -#### Custody - -[TO BE REMOVED IN PHASE 1] Verify that `len(block.body.custody_reseeds) == len(block.body.custody_challenges) == len(block.body.custody_responses) == 0`. - ## Per-epoch processing The steps below happen when `state.slot % EPOCH_LENGTH == 0`. From 109ac8969774188011a94ad2ed36e21687c59f09 Mon Sep 17 00:00:00 2001 From: Justin Date: Wed, 23 Jan 2019 09:57:48 +0000 Subject: [PATCH 07/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index a47cad399..4d900cfe8 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -30,6 +30,7 @@ - [Attestations](#attestations) - [`Attestation`](#attestation) - [`AttestationData`](#attestationdata) + - [`AttestationDataWrapped`](#attestationdatawrapped) - [Deposits](#deposits) - [`Deposit`](#deposit) - [`DepositData`](#depositdata) @@ -290,12 +291,12 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be ```python { - # Validator indices - 'validator_indices': ['uint24'], # Attestation data 'data': AttestationData, # Aggregate signature 'aggregate_signature': 'bytes96', + # Validator indices + 'validator_indices': ['uint24'], } ``` @@ -337,6 +338,15 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be } ``` +#### `AttestationDataWrapped` + +```python +{ + # Attestation data + 'data': AttestationData, +} +``` + #### Deposits ##### `Deposit` @@ -1065,7 +1075,7 @@ def verify_slashable_vote_data(state: BeaconState, vote_data: SlashableVoteData) return bls_verify( pubkey=bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in vote_data.validator_indices]), - message=hash_tree_root(AttestationData(vote_data.data)), + message=hash_tree_root(AttestationDataWrapped(data=vote_data.data)), signature=vote_data.aggregate_signature, domain=get_domain(state.fork, vote_data.data.slot, DOMAIN_ATTESTATION), ) @@ -1460,7 +1470,7 @@ For each `attestation` in `block.body.attestations`: * `aggregate_signature` verification: * Let `participants = get_attestation_participants(state, attestation.data, attestation.aggregation_bitfield)`. * Let `group_public_key = bls_aggregate_pubkeys([state.validator_registry[v].pubkey for v in participants])`. - * Verify that `bls_verify(pubkey=group_public_key, message=hash_tree_root(AttestationData(attestation.data)), signature=attestation.aggregate_signature, domain=get_domain(state.fork, attestation.data.slot, DOMAIN_ATTESTATION))`. + * Verify that `bls_verify(pubkey=group_public_key, message=hash_tree_root(AttestationDataWrapped(data=attestation.data)), signature=attestation.aggregate_signature, domain=get_domain(state.fork, attestation.data.slot, DOMAIN_ATTESTATION))`. * [TO BE REMOVED IN PHASE 1] Verify that `attestation.data.shard_block_root == ZERO_HASH`. * Append `PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, slot_included=state.slot)` to `state.latest_attestations`. From 696a6c140a23dc900cc31878c584daecd022488d Mon Sep 17 00:00:00 2001 From: Justin Date: Wed, 23 Jan 2019 12:40:59 +0000 Subject: [PATCH 08/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 121 +++++++++++++++++++++++++++++------ 1 file changed, 101 insertions(+), 20 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 4d900cfe8..865c4c175 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -30,7 +30,7 @@ - [Attestations](#attestations) - [`Attestation`](#attestation) - [`AttestationData`](#attestationdata) - - [`AttestationDataWrapped`](#attestationdatawrapped) + - [`AttestationDataAndCustodyBit`](#attestationdataandcustodybit) - [Deposits](#deposits) - [`Deposit`](#deposit) - [`DepositData`](#depositdata) @@ -80,10 +80,13 @@ - [`get_effective_balance`](#get_effective_balance) - [`get_fork_version`](#get_fork_version) - [`get_domain`](#get_domain) + - [`get_bitfield_bit`](#get_bitfield_bit) + - [`verify_bitfield`](#verify_bitfield) - [`verify_slashable_vote_data`](#verify_slashable_vote_data) - [`is_double_vote`](#is_double_vote) - [`is_surround_vote`](#is_surround_vote) - [`integer_squareroot`](#integer_squareroot) + - [`indices`](#indices) - [`bls_verify`](#bls_verify) - [`bls_verify_multiple`](#bls_verify_multiple) - [`bls_aggregate_pubkeys`](#bls_aggregate_pubkeys) @@ -251,6 +254,13 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `DOMAIN_EXIT` | `3` | | `DOMAIN_RANDAO` | `4` | +### Custody bits + +| Name | Value | +| - | - | +| `CUSTODY_BIT_ZERO` | `False` | +| `CUSTODY_BIT_ONE` | `True` | + ## Data structures ### Beacon chain operations @@ -291,12 +301,14 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be ```python { + # Validator indices with custody bit equal to 0 + 'custody_bit_0_indices': ['uint24'], + # Validator indices with custody bit equal to 1 + 'custody_bit_1_indices': ['uint24'], # Attestation data 'data': AttestationData, # Aggregate signature 'aggregate_signature': 'bytes96', - # Validator indices - 'validator_indices': ['uint24'], } ``` @@ -310,6 +322,8 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'data': AttestationData, # Attester aggregation bitfield 'aggregation_bitfield': 'bytes', + # Custody bitfield + 'custody_bitfield': 'bytes', # BLS aggregate signature 'aggregate_signature': 'bytes96', } @@ -338,12 +352,14 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be } ``` -#### `AttestationDataWrapped` +##### `AttestationDataAndCustodyBit` ```python { # Attestation data 'data': AttestationData, + # Custody bit + 'custody_bit': bool, } ``` @@ -537,6 +553,8 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'data': AttestationData, # Attester aggregation bitfield 'aggregation_bitfield': 'bytes', + # Custody bitfield + 'custody_bitfield': 'bytes', # Slot the attestation was included 'slot_included': 'uint64', } @@ -1008,22 +1026,20 @@ def merkle_root(values: List[Bytes32]) -> Bytes32: ```python def get_attestation_participants(state: BeaconState, attestation_data: AttestationData, - aggregation_bitfield: bytes) -> List[int]: + bitfield: bytes) -> List[int]: """ - Returns the participant indices at for the ``attestation_data`` and ``aggregation_bitfield``. + Returns the participant indices at for the ``attestation_data`` and ``bitfield``. """ - # Find the committee in the list with the desired shard crosslink_committees = get_crosslink_committees_at_slot(state, attestation_data.slot) assert attestation_data.shard in [shard for _, shard in crosslink_committees] crosslink_committee = [committee for committee, shard in crosslink_committees if shard == attestation_data.shard][0] - assert len(aggregation_bitfield) == (len(committee) + 7) // 8 # Find the participating attesters in the committee participants = [] for i, validator_index in enumerate(crosslink_committee): - aggregation_bit = (aggregation_bitfield[i // 8] >> (7 - (i % 8))) % 2 + aggregation_bit = get_bitfield_bit(bitfield, i) if aggregation_bit == 1: participants.append(validator_index) return participants @@ -1066,18 +1082,51 @@ def get_domain(fork: Fork, ) * 2**32 + domain_type ``` +#### `get_bitfield_bit` + +```python +def get_bitfield_bit(bitfield: bytes, i: int) -> int: + return (bitfield[i // 8] >> (7 - (i % 8))) % 2 +``` + +#### `verify_bitfield` + +```python +def verify_bitfield(bitfield: bytes, size: int) -> bool: + ``` + Verify ``bitfield`` against the ``size``. + if len(bitfield) != (size + 7) // 8: + return False + + for i in range(size + 1, size + size % 8 + 8): + if get_bitfield_bit(bitfield, i) != 0: + return False + + return True +``` + #### `verify_slashable_vote_data` ```python -def verify_slashable_vote_data(state: BeaconState, vote_data: SlashableVoteData) -> bool: - if len(vote_data.validator_indices) > MAX_CASPER_VOTES: +def verify_slashable_vote_data(state: BeaconState, slashable_vote_data: SlashableVoteData) -> bool: + # [TO BE REMOVED IN PHASE 1] + if len(slashable_vote_data.custody_bit_1_indices) > 0: + return False + + if len(indices(slashable_vote_data)) > MAX_CASPER_VOTES: return False return bls_verify( - pubkey=bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in vote_data.validator_indices]), - message=hash_tree_root(AttestationDataWrapped(data=vote_data.data)), - signature=vote_data.aggregate_signature, - domain=get_domain(state.fork, vote_data.data.slot, DOMAIN_ATTESTATION), + pubkeys=[ + bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in slashable_vote_data.custody_bit_0_indices]), + bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in slashable_vote_data.custody_bit_1_indices]), + ], + messages=[ + hash_tree_root(AttestationDataAndCustodyBit(slashable_vote_data.data, CUSTODY_BIT_ZERO)), + hash_tree_root(AttestationDataAndCustodyBit(slashable_vote_data.data, CUSTODY_BIT_ONE)), + ], + signature=slashable_vote_data.aggregate_signature, + domain=get_domain(state.fork, slashable_vote_data.data.slot, DOMAIN_ATTESTATION), ) ``` @@ -1135,6 +1184,16 @@ def integer_squareroot(n: int) -> int: return x ``` +#### `indices` + +```python +def indices(slashable_vote_data: SlashableVoteData) -> List[int]: + """ + Return all indicies in ``slashable_vote_data``. + """ + return slashable_vote_data.custody_bit_0_indices + slashable_vote_data.custody_bit_1_indices +``` + #### `bls_verify` `bls_verify` is a function for verifying a BLS signature, defined in the [BLS Signature spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/bls_signature.md#bls_verify). @@ -1448,7 +1507,7 @@ For each `casper_slashing` in `block.body.casper_slashings`: * Let `slashable_vote_data_1 = casper_slashing.slashable_vote_data_1`. * Let `slashable_vote_data_2 = casper_slashing.slashable_vote_data_2`. -* Let `intersection = [x for x in slashable_vote_data_1.validator_indices if x in slashable_vote_data_2.validator_indices]`. +* Let `intersection = [x for x in indices(slashable_vote_data_1) if x in indices(slashable_vote_data_2)]`. * Verify that `len(intersection) >= 1`. * Verify that `slashable_vote_data_1.data != slashable_vote_data_2.data`. * Verify that `is_double_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)` or `is_surround_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)`. @@ -1467,10 +1526,32 @@ For each `attestation` in `block.body.attestations`: * Verify that `attestation.data.justified_slot` is equal to `state.justified_slot if attestation.data.slot >= state.slot - (state.slot % EPOCH_LENGTH) else state.previous_justified_slot`. * Verify that `attestation.data.justified_block_root` is equal to `get_block_root(state, attestation.data.justified_slot)`. * Verify that either `attestation.data.latest_crosslink_root` or `attestation.data.shard_block_root` equals `state.latest_crosslinks[shard].shard_block_root`. -* `aggregate_signature` verification: - * Let `participants = get_attestation_participants(state, attestation.data, attestation.aggregation_bitfield)`. - * Let `group_public_key = bls_aggregate_pubkeys([state.validator_registry[v].pubkey for v in participants])`. - * Verify that `bls_verify(pubkey=group_public_key, message=hash_tree_root(AttestationDataWrapped(data=attestation.data)), signature=attestation.aggregate_signature, domain=get_domain(state.fork, attestation.data.slot, DOMAIN_ATTESTATION))`. +* `attestation.aggregate_signature` verification: + +```python + assert verify_bitfield(attestation.aggregation_bitfield) + assert verify_bitfield(attestation.custody_bitfield) + assert attestation.custody_bitfield & attestation.aggregation_bitfield == attestation.custody_bitfield + + participants = get_attestation_participants(state, attestation.data, attestation.aggregation_bitfield) + custody_bit_0_participants = get_attestation_participants(state, attestation.data, attestation.custody_bitfield) + custody_bit_1_participants = [i in participants for i not in custody_bit_0_participants] + + assert bls_verify_multiple( + pubkeys=[ + bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in custody_bit_0_participants]), + bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in custody_bit_1_participants]), + ], + messages=[ + hash_tree_root(AttestationDataAndCustodyBit(data=attestation.data, custody_bit=CUSTODY_BIT_ZERO)), + hash_tree_root(AttestationDataAndCustodyBit(data=attestation.data, custody_bit=CUSTODY_BIT_ONE)), + ], + signature=attestation.aggregate_signature, + domain=get_domain(state.fork, attestation.data.slot, DOMAIN_ATTESTATION), + ) + +``` + * [TO BE REMOVED IN PHASE 1] Verify that `attestation.data.shard_block_root == ZERO_HASH`. * Append `PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, slot_included=state.slot)` to `state.latest_attestations`. From ee081e160ca93eddd3bab9c59ed2d6a6a5979fb2 Mon Sep 17 00:00:00 2001 From: Justin Date: Wed, 23 Jan 2019 12:47:11 +0000 Subject: [PATCH 09/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 865c4c175..ecbcdebb1 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1526,13 +1526,17 @@ For each `attestation` in `block.body.attestations`: * Verify that `attestation.data.justified_slot` is equal to `state.justified_slot if attestation.data.slot >= state.slot - (state.slot % EPOCH_LENGTH) else state.previous_justified_slot`. * Verify that `attestation.data.justified_block_root` is equal to `get_block_root(state, attestation.data.justified_slot)`. * Verify that either `attestation.data.latest_crosslink_root` or `attestation.data.shard_block_root` equals `state.latest_crosslinks[shard].shard_block_root`. -* `attestation.aggregate_signature` verification: +* Verify bitfields: ```python assert verify_bitfield(attestation.aggregation_bitfield) assert verify_bitfield(attestation.custody_bitfield) assert attestation.custody_bitfield & attestation.aggregation_bitfield == attestation.custody_bitfield +``` +* Verify aggregate signature: + +```python participants = get_attestation_participants(state, attestation.data, attestation.aggregation_bitfield) custody_bit_0_participants = get_attestation_participants(state, attestation.data, attestation.custody_bitfield) custody_bit_1_participants = [i in participants for i not in custody_bit_0_participants] From ac85e06e81f0664a5177478a9f3d37efeb255004 Mon Sep 17 00:00:00 2001 From: Justin Date: Wed, 23 Jan 2019 12:48:54 +0000 Subject: [PATCH 10/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index ecbcdebb1..3a79ee71d 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1109,8 +1109,7 @@ def verify_bitfield(bitfield: bytes, size: int) -> bool: ```python def verify_slashable_vote_data(state: BeaconState, slashable_vote_data: SlashableVoteData) -> bool: - # [TO BE REMOVED IN PHASE 1] - if len(slashable_vote_data.custody_bit_1_indices) > 0: + if len(slashable_vote_data.custody_bit_1_indices) > 0: # [TO BE REMOVED IN PHASE 1] return False if len(indices(slashable_vote_data)) > MAX_CASPER_VOTES: @@ -1532,6 +1531,7 @@ For each `attestation` in `block.body.attestations`: assert verify_bitfield(attestation.aggregation_bitfield) assert verify_bitfield(attestation.custody_bitfield) assert attestation.custody_bitfield & attestation.aggregation_bitfield == attestation.custody_bitfield + assert attestation.custody_bitfield == 0 # [TO BE REMOVED IN PHASE 1] ``` * Verify aggregate signature: From 1e48535edd4e80779008a17a1eef1eb66d13ca32 Mon Sep 17 00:00:00 2001 From: Justin Date: Wed, 23 Jan 2019 12:57:06 +0000 Subject: [PATCH 11/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 3a79ee71d..151e5f696 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1557,7 +1557,7 @@ For each `attestation` in `block.body.attestations`: ``` * [TO BE REMOVED IN PHASE 1] Verify that `attestation.data.shard_block_root == ZERO_HASH`. -* Append `PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, slot_included=state.slot)` to `state.latest_attestations`. +* Append `PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, custody_bitfield=attestation.custody_bitfield, slot_included=state.slot)` to `state.latest_attestations`. #### Deposits From e3a5720c1b7587e69cdebb453a6ae07e9d198e80 Mon Sep 17 00:00:00 2001 From: Justin Date: Wed, 23 Jan 2019 13:03:33 +0000 Subject: [PATCH 12/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 1 + 1 file changed, 1 insertion(+) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 151e5f696..585ff5223 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -20,6 +20,7 @@ - [Max operations per block](#max-operations-per-block) - [Validator registry delta flags](#validator-registry-delta-flags) - [Signature domains](#signature-domains) + - [Custody bits](#custody-bits) - [Data structures](#data-structures) - [Beacon chain operations](#beacon-chain-operations) - [Proposer slashings](#proposer-slashings) From d1efd65d8a53a1e69b087cf30f7830eb36dd1acf Mon Sep 17 00:00:00 2001 From: Justin Date: Wed, 23 Jan 2019 13:24:35 +0000 Subject: [PATCH 13/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 46 +++++++++++++++++++++--------------- 1 file changed, 27 insertions(+), 19 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 585ff5223..ac3a00a37 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -302,10 +302,10 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be ```python { - # Validator indices with custody bit equal to 0 - 'custody_bit_0_indices': ['uint24'], - # Validator indices with custody bit equal to 1 - 'custody_bit_1_indices': ['uint24'], + # Validator indices + 'validator_indices': '[uint24]', + # Custody bitfield + 'custody_bitfield': 'bytes', # Attestation data 'data': AttestationData, # Aggregate signature @@ -1110,16 +1110,34 @@ def verify_bitfield(bitfield: bytes, size: int) -> bool: ```python def verify_slashable_vote_data(state: BeaconState, slashable_vote_data: SlashableVoteData) -> bool: - if len(slashable_vote_data.custody_bit_1_indices) > 0: # [TO BE REMOVED IN PHASE 1] + if slashable_vote_data.custody_bitfield != 0: # [TO BE REMOVED IN PHASE 1] return False - if len(indices(slashable_vote_data)) > MAX_CASPER_VOTES: + if len(slashable_vote_data.validator_indices) == 0: return False + for i in range(len(slashable_vote_data.validator_indices) - 1): + if slashable_vote_data.validator_indices[i] >= slashable_vote_data.validator_indices[i + 1]: + return False + + if not verify_bitfield(slashable_vote_data.custody_bitfield, len(slashable_vote_data.validator_indices)): + return False + + if len(slashable_vote_data.validator_indices) > MAX_CASPER_VOTES: + return False + + custody_bit_0_indices = [] + custody_bit_1_indices = [] + for i, validator_index in enumerate(slashable_vote_data.validator_indices): + if get_bitfield_bit(slashable_vote_data.custody_bitfield, i) == 0: + custody_bit_0_indices.append(validator_index) + else: + custody_bit_1_indices.append(validator_index) + return bls_verify( pubkeys=[ - bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in slashable_vote_data.custody_bit_0_indices]), - bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in slashable_vote_data.custody_bit_1_indices]), + bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in custody_bit_0_indices]), + bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in custody_bit_1_indices]), ], messages=[ hash_tree_root(AttestationDataAndCustodyBit(slashable_vote_data.data, CUSTODY_BIT_ZERO)), @@ -1184,16 +1202,6 @@ def integer_squareroot(n: int) -> int: return x ``` -#### `indices` - -```python -def indices(slashable_vote_data: SlashableVoteData) -> List[int]: - """ - Return all indicies in ``slashable_vote_data``. - """ - return slashable_vote_data.custody_bit_0_indices + slashable_vote_data.custody_bit_1_indices -``` - #### `bls_verify` `bls_verify` is a function for verifying a BLS signature, defined in the [BLS Signature spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/bls_signature.md#bls_verify). @@ -1507,7 +1515,7 @@ For each `casper_slashing` in `block.body.casper_slashings`: * Let `slashable_vote_data_1 = casper_slashing.slashable_vote_data_1`. * Let `slashable_vote_data_2 = casper_slashing.slashable_vote_data_2`. -* Let `intersection = [x for x in indices(slashable_vote_data_1) if x in indices(slashable_vote_data_2)]`. +* Let `intersection = [x for x in slashable_vote_data_1.validator_indices if x in slashable_vote_data_2.validator_indices]`. * Verify that `len(intersection) >= 1`. * Verify that `slashable_vote_data_1.data != slashable_vote_data_2.data`. * Verify that `is_double_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)` or `is_surround_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)`. From 022dd0cc3d8ad239bb484cbf16d1f45bd360c951 Mon Sep 17 00:00:00 2001 From: Justin Date: Wed, 23 Jan 2019 13:26:23 +0000 Subject: [PATCH 14/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index ac3a00a37..8c6197927 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1561,8 +1561,7 @@ For each `attestation` in `block.body.attestations`: ], signature=attestation.aggregate_signature, domain=get_domain(state.fork, attestation.data.slot, DOMAIN_ATTESTATION), - ) - + ) ``` * [TO BE REMOVED IN PHASE 1] Verify that `attestation.data.shard_block_root == ZERO_HASH`. From 6f3cb7e7e5991366f5dbfbc729d739edcf698a94 Mon Sep 17 00:00:00 2001 From: Justin Date: Wed, 23 Jan 2019 13:28:43 +0000 Subject: [PATCH 15/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 8c6197927..a708a30a8 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -255,13 +255,6 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `DOMAIN_EXIT` | `3` | | `DOMAIN_RANDAO` | `4` | -### Custody bits - -| Name | Value | -| - | - | -| `CUSTODY_BIT_ZERO` | `False` | -| `CUSTODY_BIT_ONE` | `True` | - ## Data structures ### Beacon chain operations @@ -1140,8 +1133,8 @@ def verify_slashable_vote_data(state: BeaconState, slashable_vote_data: Slashabl bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in custody_bit_1_indices]), ], messages=[ - hash_tree_root(AttestationDataAndCustodyBit(slashable_vote_data.data, CUSTODY_BIT_ZERO)), - hash_tree_root(AttestationDataAndCustodyBit(slashable_vote_data.data, CUSTODY_BIT_ONE)), + hash_tree_root(AttestationDataAndCustodyBit(slashable_vote_data.data, 0)), + hash_tree_root(AttestationDataAndCustodyBit(slashable_vote_data.data, 1)), ], signature=slashable_vote_data.aggregate_signature, domain=get_domain(state.fork, slashable_vote_data.data.slot, DOMAIN_ATTESTATION), @@ -1556,8 +1549,8 @@ For each `attestation` in `block.body.attestations`: bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in custody_bit_1_participants]), ], messages=[ - hash_tree_root(AttestationDataAndCustodyBit(data=attestation.data, custody_bit=CUSTODY_BIT_ZERO)), - hash_tree_root(AttestationDataAndCustodyBit(data=attestation.data, custody_bit=CUSTODY_BIT_ONE)), + hash_tree_root(AttestationDataAndCustodyBit(data=attestation.data, custody_bit=0)), + hash_tree_root(AttestationDataAndCustodyBit(data=attestation.data, custody_bit=1)), ], signature=attestation.aggregate_signature, domain=get_domain(state.fork, attestation.data.slot, DOMAIN_ATTESTATION), From dfaf24c75e3df6aaaabab88bfd6115c23928dc77 Mon Sep 17 00:00:00 2001 From: Justin Date: Wed, 23 Jan 2019 13:52:52 +0000 Subject: [PATCH 16/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index a708a30a8..5c0663242 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -20,7 +20,6 @@ - [Max operations per block](#max-operations-per-block) - [Validator registry delta flags](#validator-registry-delta-flags) - [Signature domains](#signature-domains) - - [Custody bits](#custody-bits) - [Data structures](#data-structures) - [Beacon chain operations](#beacon-chain-operations) - [Proposer slashings](#proposer-slashings) @@ -1080,6 +1079,9 @@ def get_domain(fork: Fork, ```python def get_bitfield_bit(bitfield: bytes, i: int) -> int: + """ + Extract the bit in ``bitfield`` at position ``i``. + """ return (bitfield[i // 8] >> (7 - (i % 8))) % 2 ``` @@ -1087,12 +1089,13 @@ def get_bitfield_bit(bitfield: bytes, i: int) -> int: ```python def verify_bitfield(bitfield: bytes, size: int) -> bool: - ``` + """ Verify ``bitfield`` against the ``size``. + """ if len(bitfield) != (size + 7) // 8: return False - for i in range(size + 1, size + size % 8 + 8): + for i in range(size + 1, size - size % 8 + 8): if get_bitfield_bit(bitfield, i) != 0: return False @@ -1103,6 +1106,9 @@ def verify_bitfield(bitfield: bytes, size: int) -> bool: ```python def verify_slashable_vote_data(state: BeaconState, slashable_vote_data: SlashableVoteData) -> bool: + """ + Verify validity of ``slashable_vote_data`` fields. + """ if slashable_vote_data.custody_bitfield != 0: # [TO BE REMOVED IN PHASE 1] return False From dd075edd06e5069b38a0cd929f220db95765472d Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Wed, 23 Jan 2019 15:30:05 -0600 Subject: [PATCH 17/70] epoch trans at end of epoch and fix finality conditions --- specs/core/0_beacon-chain.md | 39 +++++++++++++++++++++++------------- 1 file changed, 25 insertions(+), 14 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index d58d49df8..cedd48172 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1570,10 +1570,13 @@ For each `exit` in `block.body.exits`: ## Per-epoch processing -The steps below happen when `state.slot % EPOCH_LENGTH == 0`. +The steps below happen when `state.slot % EPOCH_LENGTH == EPOCH_LENGTH - 1`. ### Helpers +* Let `current_epoch_start_slot = state.slot - (EPOCH_LENGTH + 1)`. +* Let `previous_epoch_start_slot = state.slot - 2 * EPOCH_LENGTH + 1` if `state.slot > EPOCH_LENGTH` else `current_epoch_start_slot`. + All [validators](#dfn-validator): * Let `active_validator_indices = get_active_validator_indices(state.validator_registry, state.slot)`. @@ -1581,23 +1584,23 @@ All [validators](#dfn-validator): [Validators](#dfn-Validator) attesting during the current epoch: -* Let `current_epoch_attestations = [a for a in state.latest_attestations if state.slot - EPOCH_LENGTH <= a.data.slot < state.slot]`. (Note: this is the set of attestations of slots in the epoch `state.slot-EPOCH_LENGTH...state.slot-1`, _not_ attestations that got included in the chain during the epoch `state.slot-EPOCH_LENGTH...state.slot-1`.) +* Let `current_epoch_attestations = [a for a in state.latest_attestations if current_epoch_start_slot <= a.data.slot <= state.slot]`. (Note: this is the set of attestations of slots in the epoch `current_epoch_start_slot...state.slot`, _not_ attestations that got included in the chain during the epoch `current_epoch_start_slot...state.slot`.) * Validators justifying the epoch boundary block at the start of the current epoch: - * Let `current_epoch_boundary_attestations = [a for a in current_epoch_attestations if a.data.epoch_boundary_root == get_block_root(state, state.slot-EPOCH_LENGTH) and a.data.justified_slot == state.justified_slot]`. + * Let `current_epoch_boundary_attestations = [a for a in current_epoch_attestations if a.data.epoch_boundary_root == get_block_root(state, current_epoch_start_slot) and a.data.justified_slot == state.justified_slot]`. * Let `current_epoch_boundary_attester_indices` be the union of the [validator](#dfn-validator) index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in current_epoch_boundary_attestations]`. * Let `current_epoch_boundary_attesting_balance = sum([get_effective_balance(state, i) for i in current_epoch_boundary_attester_indices])`. [Validators](#dfn-Validator) attesting during the previous epoch: * Validators that made an attestation during the previous epoch: - * Let `previous_epoch_attestations = [a for a in state.latest_attestations if state.slot - 2 * EPOCH_LENGTH <= a.data.slot < state.slot - EPOCH_LENGTH]`. + * Let `previous_epoch_attestations = [a for a in state.latest_attestations if previous_epoch_start_slot <= a.data.slot < current_epoch_start_slot]`. * Let `previous_epoch_attester_indices` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in previous_epoch_attestations]`. * Validators targeting the previous justified slot: * Let `previous_epoch_justified_attestations = [a for a in current_epoch_attestations + previous_epoch_attestations if a.data.justified_slot == state.previous_justified_slot]`. * Let `previous_epoch_justified_attester_indices` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in previous_epoch_justified_attestations]`. * Let `previous_epoch_justified_attesting_balance = sum([get_effective_balance(state, i) for i in previous_epoch_justified_attester_indices])`. * Validators justifying the epoch boundary block at the start of the previous epoch: - * Let `previous_epoch_boundary_attestations = [a for a in previous_epoch_justified_attestations if a.data.epoch_boundary_root == get_block_root(state, state.slot - 2 * EPOCH_LENGTH)]`. + * Let `previous_epoch_boundary_attestations = [a for a in previous_epoch_justified_attestations if a.data.epoch_boundary_root == get_block_root(state, previous_epoch_start_slot)]`. * Let `previous_epoch_boundary_attester_indices` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in previous_epoch_boundary_attestations]`. * Let `previous_epoch_boundary_attesting_balance = sum([get_effective_balance(state, i) for i in previous_epoch_boundary_attester_indices])`. * Validators attesting to the expected beacon chain head during the previous epoch: @@ -1623,23 +1626,31 @@ Define the following helpers to process attestation inclusion rewards and inclus ### Eth1 data -If `state.slot % ETH1_DATA_VOTING_PERIOD == 0`: +If `state.slot % ETH1_DATA_VOTING_PERIOD == ETH1_DATA_VOTING_PERIOD - 1`: * Set `state.latest_eth1_data = eth1_data_vote.data` if `eth1_data_vote.vote_count * 2 > ETH1_DATA_VOTING_PERIOD` for some `eth1_data_vote` in `state.eth1_data_votes`. * Set `state.eth1_data_votes = []`. ### Justification -* Set `state.previous_justified_slot = state.justified_slot`. +First, update the justification bitfield: + +* Let `new_justified_slot = state.justified_slot`. * Set `state.justification_bitfield = (state.justification_bitfield * 2) % 2**64`. -* Set `state.justification_bitfield |= 2` and `state.justified_slot = state.slot - 2 * EPOCH_LENGTH` if `3 * previous_epoch_boundary_attesting_balance >= 2 * total_balance`. -* Set `state.justification_bitfield |= 1` and `state.justified_slot = state.slot - 1 * EPOCH_LENGTH` if `3 * current_epoch_boundary_attesting_balance >= 2 * total_balance`. +* Set `state.justification_bitfield |= 2` and `new_justified_slot = previous_epoch_start_slot` if `3 * previous_epoch_boundary_attesting_balance >= 2 * total_balance`. +* Set `state.justification_bitfield |= 1` and `new_justified_slot = current_epoch_start_slot` if `3 * current_epoch_boundary_attesting_balance >= 2 * total_balance`. -Set `state.finalized_slot = state.previous_justified_slot` if any of the following are true: +Next, update last finalized slot if possible: -* `state.previous_justified_slot == state.slot - 2 * EPOCH_LENGTH and state.justification_bitfield % 4 == 3` -* `state.previous_justified_slot == state.slot - 3 * EPOCH_LENGTH and state.justification_bitfield % 8 == 7` -* `state.previous_justified_slot == state.slot - 4 * EPOCH_LENGTH and state.justification_bitfield % 16 in (15, 14)` +* Set `state.finalized_slot = state.justified_slot` if `(state.justification_bitfield >> 0) % 4 == 0b11 and state.justified_slot == previous_epoch_start_slot`. +* Set `state.finalized_slot = state.previous_justified_slot` if `(state.justification_bitfield >> 1) % 4 == 0b11 and state.previous_justified_slot == previous_epoch_start_slot - EPOCH_LENGTH`. +* Set `state.finalized_slot = state.justified_slot` if `(state.justification_bitfield >> 0) % 8 == 0b111 and state.justified_slot == previous_epoch_start_slot - EPOCH_LENGTH`. +* Set `state.finalized_slot = state.previous_justified_slot` if `(state.justification_bitfield >> 1) % 8 == 0b111 and state.previous_justified_slot == previous_epoch_start_slot - 2 * EPOCH_LENGTH`. + +Finally, update the following: + +* Set `state.previous_justified_slot = state.justified_slot`. +* Set `state.justified_slot = justified_slot`. ### Crosslinks @@ -1819,7 +1830,7 @@ def process_penalties_and_exits(state: BeaconState) -> None: ### Final updates * Let `e = state.slot // EPOCH_LENGTH`. Set `state.latest_penalized_balances[(e+1) % LATEST_PENALIZED_EXIT_LENGTH] = state.latest_penalized_balances[e % LATEST_PENALIZED_EXIT_LENGTH]` -* Remove any `attestation` in `state.latest_attestations` such that `attestation.data.slot < state.slot - EPOCH_LENGTH`. +* Remove any `attestation` in `state.latest_attestations` such that `attestation.data.slot < current_epoch_start_slot`. ## State root processing From b18de2c86cdd812d072728ee094b3f7915474460 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Wed, 23 Jan 2019 15:41:25 -0600 Subject: [PATCH 18/70] clena up get_crosslink_committees_at_slots --- specs/core/0_beacon-chain.md | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index cedd48172..013676f55 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -942,24 +942,25 @@ def get_crosslink_committees_at_slot(state: BeaconState, state_epoch_slot = state.slot - (state.slot % EPOCH_LENGTH) assert state_epoch_slot <= slot + EPOCH_LENGTH assert slot < state_epoch_slot + EPOCH_LENGTH - offset = slot % EPOCH_LENGTH if slot < state_epoch_slot: committees_per_slot = get_previous_epoch_committee_count_per_slot(state) - shuffling = get_shuffling( - state.previous_epoch_randao_mix, - state.validator_registry, - state.previous_epoch_calculation_slot, - ) - slot_start_shard = (state.previous_epoch_start_shard + committees_per_slot * offset) % SHARD_COUNT + seed = state.previous_epoch_randao_mix + shuffling_slot = state.previous_epoch_calculation_slot + shuffling_start_shard = state.previous_epoch_start_shard else: committees_per_slot = get_current_epoch_committee_count_per_slot(state) - shuffling = get_shuffling( - state.current_epoch_randao_mix, - state.validator_registry, - state.current_epoch_calculation_slot, - ) - slot_start_shard = (state.current_epoch_start_shard + committees_per_slot * offset) % SHARD_COUNT + seed = state.current_epoch_randao_mix + shuffling_slot = state.current_epoch_calculation_slot + shuffling_start_shard = state.current_epoch_start_shard + + shuffling = get_shuffling( + seed, + state.validator_registry, + shuffling_slot, + ) + offset = slot % EPOCH_LENGTH + slot_start_shard = (shuffling_start_shard + committees_per_slot * offset) % SHARD_COUNT return [ ( From 1aceaeb793f620de01087fee1221029f486dcd6e Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Wed, 23 Jan 2019 17:14:38 -0600 Subject: [PATCH 19/70] reverse ordering of finality conditions --- specs/core/0_beacon-chain.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 013676f55..dfb41ab47 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1643,10 +1643,10 @@ First, update the justification bitfield: Next, update last finalized slot if possible: -* Set `state.finalized_slot = state.justified_slot` if `(state.justification_bitfield >> 0) % 4 == 0b11 and state.justified_slot == previous_epoch_start_slot`. +* Set `state.finalized_slot = state.previous_justified_slot` if `(state.justification_bitfield >> 1) % 8 == 0b111 and state.previous_justified_slot == previous_epoch_start_slot - 2 * EPOCH_LENGTH`. * Set `state.finalized_slot = state.previous_justified_slot` if `(state.justification_bitfield >> 1) % 4 == 0b11 and state.previous_justified_slot == previous_epoch_start_slot - EPOCH_LENGTH`. * Set `state.finalized_slot = state.justified_slot` if `(state.justification_bitfield >> 0) % 8 == 0b111 and state.justified_slot == previous_epoch_start_slot - EPOCH_LENGTH`. -* Set `state.finalized_slot = state.previous_justified_slot` if `(state.justification_bitfield >> 1) % 8 == 0b111 and state.previous_justified_slot == previous_epoch_start_slot - 2 * EPOCH_LENGTH`. +* Set `state.finalized_slot = state.justified_slot` if `(state.justification_bitfield >> 0) % 4 == 0b11 and state.justified_slot == previous_epoch_start_slot`. Finally, update the following: From df85857c2edb700f9882eae888561a6eb99519b6 Mon Sep 17 00:00:00 2001 From: vbuterin Date: Wed, 23 Jan 2019 20:35:26 -0600 Subject: [PATCH 20/70] A few more state.slot -> current/previous/next epoch start slot changes --- specs/core/0_beacon-chain.md | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index dfb41ab47..2fa4c151c 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1575,12 +1575,13 @@ The steps below happen when `state.slot % EPOCH_LENGTH == EPOCH_LENGTH - 1`. ### Helpers +* Let `next_epoch_start_slot = state.slot + 1`. * Let `current_epoch_start_slot = state.slot - (EPOCH_LENGTH + 1)`. * Let `previous_epoch_start_slot = state.slot - 2 * EPOCH_LENGTH + 1` if `state.slot > EPOCH_LENGTH` else `current_epoch_start_slot`. All [validators](#dfn-validator): -* Let `active_validator_indices = get_active_validator_indices(state.validator_registry, state.slot)`. +* Let `active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch_start_slot)`. * Let `total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices])`. [Validators](#dfn-Validator) attesting during the current epoch: @@ -1611,7 +1612,7 @@ All [validators](#dfn-validator): **Note**: `previous_epoch_boundary_attesting_balance` balance might be marginally different than `current_epoch_boundary_attesting_balance` during the previous epoch transition. Due to the tight bound on validator churn each epoch and small per-epoch rewards/penalties, the potential balance difference is very low and only marginally affects consensus safety. -For every `slot in range(state.slot - 2 * EPOCH_LENGTH, state.slot)`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: +For every `slot in range(previous_epoch_start_slot, next_epoch_start_slot)`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: * Let `shard_block_root` be `state.latest_crosslinks[shard].shard_block_root` * Let `attesting_validator_indices(crosslink_committee, shard_block_root)` be the union of the [validator](#dfn-validator) index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in current_epoch_attestations + previous_epoch_attestations if a.data.shard == shard and a.data.shard_block_root == shard_block_root]`. @@ -1655,9 +1656,9 @@ Finally, update the following: ### Crosslinks -For every `slot in range(state.slot - 2 * EPOCH_LENGTH, state.slot)`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: +For every `slot in range(previous_epoch_start_slot, next_epoch_start_slot)`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: -* Set `state.latest_crosslinks[shard] = Crosslink(slot=state.slot, shard_block_root=winning_root(crosslink_committee))` if `3 * total_attesting_balance(crosslink_committee) >= 2 * total_balance(crosslink_committee)`. +* Set `state.latest_crosslinks[shard] = Crosslink(slot=current_epoch_start_slot, shard_block_root=winning_root(crosslink_committee))` if `3 * total_attesting_balance(crosslink_committee) >= 2 * total_balance(crosslink_committee)`. ### Rewards and penalties @@ -1671,7 +1672,7 @@ First, we define some additional helpers: Note: When applying penalties in the following balance recalculations implementers should make sure the `uint64` does not underflow. -* Let `epochs_since_finality = (state.slot - state.finalized_slot) // EPOCH_LENGTH`. +* Let `epochs_since_finality = (next_epoch_start_slot - state.finalized_slot) // EPOCH_LENGTH`. Case 1: `epochs_since_finality <= 4`: @@ -1692,7 +1693,7 @@ Case 2: `epochs_since_finality > 4`: * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_justified_attester_indices`, loses `inactivity_penalty(state, index, epochs_since_finality)`. * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_boundary_attester_indices`, loses `inactivity_penalty(state, index, epochs_since_finality)`. * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_head_attester_indices`, loses `base_reward(state, index)`. -* Any [active_validator](#dfn-active-validator) `index` with `validator.penalized_slot <= state.slot`, loses `2 * inactivity_penalty(state, index, epochs_since_finality) + base_reward(state, index)`. +* Any [active_validator](#dfn-active-validator) `index` with `validator.penalized_slot <= current_epoch_start_slot`, loses `2 * inactivity_penalty(state, index, epochs_since_finality) + base_reward(state, index)`. * Any [validator](#dfn-validator) `index` in `previous_epoch_attester_indices` loses `base_reward(state, index) - base_reward(state, index) * MIN_ATTESTATION_INCLUSION_DELAY // inclusion_distance(state, index)` #### Attestation inclusion @@ -1701,7 +1702,7 @@ For each `index` in `previous_epoch_attester_indices`, we determine the proposer #### Crosslinks -For every `slot in range(state.slot - 2 * EPOCH_LENGTH, state.slot - EPOCH_LENGTH)`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: +For every `slot in range(previous_epoch_start_slot, current_epoch_start_slot)`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: * If `index in attesting_validators(crosslink_committee)`, `state.validator_balances[index] += base_reward(state, index) * total_attesting_balance(crosslink_committee) // total_balance(crosslink_committee))`. * If `index not in attesting_validators(crosslink_committee)`, `state.validator_balances[index] -= base_reward(state, index)`. @@ -1716,7 +1717,7 @@ def process_ejections(state: BeaconState) -> None: Iterate through the validator registry and eject active validators with balance below ``EJECTION_BALANCE``. """ - for index in get_active_validator_indices(state.validator_registry, state.slot): + for index in get_active_validator_indices(state.validator_registry, current_epoch_start_slot): if state.validator_balances[index] < EJECTION_BALANCE: exit_validator(state, index) ``` @@ -1743,7 +1744,7 @@ def update_validator_registry(state: BeaconState) -> None: Note that this function mutates ``state``. """ # The active validators - active_validator_indices = get_active_validator_indices(state.validator_registry, state.slot) + active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch_start_slot) # The total effective balance of active validators total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices]) From f27905583f0cdfc2a78c98ead5d03902bcddd597 Mon Sep 17 00:00:00 2001 From: Hsiao-Wei Wang Date: Fri, 25 Jan 2019 16:01:35 +0800 Subject: [PATCH 21/70] PR feedback --- specs/core/0_beacon-chain.md | 40 ++++++++++++++++++++++-------------- 1 file changed, 25 insertions(+), 15 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 93e773976..382caeca7 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -746,26 +746,36 @@ Beacon block production is significantly different because of the proof of stake The beacon chain fork choice rule is a hybrid that combines justification and finality with Latest Message Driven (LMD) Greediest Heaviest Observed SubTree (GHOST). At any point in time a [validator](#dfn-validator) `v` subjectively calculates the beacon chain head as follows. -* Let `store` be the set of attestations and blocks that the [validator](#dfn-validator) `v` has observed and verified (in particular, block ancestors must be recursively verified). Attestations not part of any chain are still included in `store`. +* Abstractly define `Store` as the type of storage object for the chain data and `store` be the set of attestations and blocks that the [validator](#dfn-validator) `v` has observed and verified (in particular, block ancestors must be recursively verified). Attestations not part of any chain are still included in `store`. * Let `finalized_head` be the finalized block with the highest slot number. (A block `B` is finalized if there is a descendant of `B` in `store` the processing of which sets `B` as finalized.) * Let `justified_head` be the descendant of `finalized_head` with the highest slot number that has been justified for at least `EPOCH_LENGTH` slots. (A block `B` is justified if there is a descendant of `B` in `store` the processing of which sets `B` as justified.) If no such descendant exists set `justified_head` to `finalized_head`. -* Let `get_ancestor(store, block, slot)` be the ancestor of `block` with slot number `slot`. The `get_ancestor` function can be defined recursively as `def get_ancestor(store, block, slot): return block if block.slot == slot else get_ancestor(store, store.get_parent(block), slot)`. -* Let `get_latest_attestation(store, validator)` be the attestation with the highest slot number in `store` from `validator`. If several such attestations exist, use the one the [validator](#dfn-validator) `v` observed first. -* Let `get_latest_attestation_target(store, validator)` be the target block in the attestation `get_latest_attestation(store, validator)`. -* The head is `lmd_ghost(store, justified_head)` where the function `lmd_ghost` is defined below. Note that the implementation below is suboptimal; there are implementations that compute the head in time logarithmic in slot count. +* Let `get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBlock` be the ancestor of `block` with slot number `slot`. The `get_ancestor` function can be defined recursively as `def get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBlock: return block if block.slot == slot else get_ancestor(store, store.get_parent(block), slot)`. +* Let `get_latest_attestation(store: Store, validator: Validator) -> Attestation` be the attestation with the highest slot number in `store` from `validator`. If several such attestations exist, use the one the [validator](#dfn-validator) `v` observed first. +* Let `get_latest_attestation_target(store: Store, validator: Validator) -> BeaconBlock` be the target block in the attestation `get_latest_attestation(store, validator)`. +* Let `get_children(block: BeaconBlock) -> List[BeaconBlock]` returns the children blocks of the given `block`. +* Let `justified_head_state` be the `BeaconState` object after processing `justified_head`. +* The `head` is `lmd_ghost(store, justified_head_state, justified_head)` where the function `lmd_ghost` is defined below. Note that the implementation below is suboptimal; there are implementations that compute the head in time logarithmic in slot count. ```python -def lmd_ghost(store, start): - validators = start.state.validator_registry - active_validators = [validators[i] for i in - get_active_validator_indices(validators, start.state.slot)] - attestation_targets = [get_latest_attestation_target(store, validator) - for validator in active_validators] - def get_vote_count(block): - return len([target for target in attestation_targets if - get_ancestor(store, target, block.slot) == block]) +def lmd_ghost(store: Store, start_state: BeaconState, start_block: BeaconBlock) -> BeaconBlock: + validators = start_state.validator_registry + active_validators = [ + validators[i] + for i in get_active_validator_indices(validators, start_state.slot) + ] + attestation_targets = [ + get_latest_attestation_target(store, validator) + for validator in active_validators + ] - head = start + def get_vote_count(block: BeaconBlock) -> int: + return len([ + target + for target in attestation_targets + if get_ancestor(store, target, block.slot) == block + ]) + + head = start_block while 1: children = get_children(head) if len(children) == 0: From 21cecba6bb24bdbb0e57cefab76c2b550527c89a Mon Sep 17 00:00:00 2001 From: Hsiao-Wei Wang Date: Fri, 25 Jan 2019 16:06:05 +0800 Subject: [PATCH 22/70] Update `get_children` def --- specs/core/0_beacon-chain.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 382caeca7..a4440e924 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -752,7 +752,7 @@ The beacon chain fork choice rule is a hybrid that combines justification and fi * Let `get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBlock` be the ancestor of `block` with slot number `slot`. The `get_ancestor` function can be defined recursively as `def get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBlock: return block if block.slot == slot else get_ancestor(store, store.get_parent(block), slot)`. * Let `get_latest_attestation(store: Store, validator: Validator) -> Attestation` be the attestation with the highest slot number in `store` from `validator`. If several such attestations exist, use the one the [validator](#dfn-validator) `v` observed first. * Let `get_latest_attestation_target(store: Store, validator: Validator) -> BeaconBlock` be the target block in the attestation `get_latest_attestation(store, validator)`. -* Let `get_children(block: BeaconBlock) -> List[BeaconBlock]` returns the children blocks of the given `block`. +* Let `get_children(store: Store, block: BeaconBlock) -> List[BeaconBlock]` returns the children blocks of the given `block`. * Let `justified_head_state` be the `BeaconState` object after processing `justified_head`. * The `head` is `lmd_ghost(store, justified_head_state, justified_head)` where the function `lmd_ghost` is defined below. Note that the implementation below is suboptimal; there are implementations that compute the head in time logarithmic in slot count. @@ -777,7 +777,7 @@ def lmd_ghost(store: Store, start_state: BeaconState, start_block: BeaconBlock) head = start_block while 1: - children = get_children(head) + children = get_children(store, head) if len(children) == 0: return head head = max(children, key=get_vote_count) From ddf420ba3981e16225d708600960eb2d7843f08b Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Fri, 25 Jan 2019 16:07:54 -0700 Subject: [PATCH 23/70] work through issues with epochs, seeds, etc) --- specs/core/0_beacon-chain.md | 46 ++++++++++++++++++++++++++++-------- 1 file changed, 36 insertions(+), 10 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 8addc31a4..f924d2dc7 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -72,6 +72,7 @@ - [`get_block_root`](#get_block_root) - [`get_randao_mix`](#get_randao_mix) - [`get_active_index_root`](#get_active_index_root) + - [`generate_seed`](#generate_seed) - [`get_beacon_proposer_index`](#get_beacon_proposer_index) - [`merkle_root`](#merkle_root) - [`get_attestation_participants`](#get_attestation_participants) @@ -998,6 +999,27 @@ def get_active_index_root(state: BeaconState, return state.latest_index_roots[given_epoch % LATEST_INDEX_ROOTS_LENGTH] ``` +#### `generate_seed` + +```python +def generate_seed(state: BeaconState, + slot: int) -> Bytes32: + """ + Generate a seed for the given ``slot``. + """ + if slot < SEED_LOOKAHEAD: + randao_mix_slot = GENESIS_SLOT + else: + randao_mix_slot = slot - SEED_LOOKAHEAD + + return hash( + get_randao_mix(state, randao_mix_slot) + + get_active_index_root(state, slot) + ) + +``` + + #### `get_beacon_proposer_index` ```python @@ -1285,6 +1307,9 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], if get_effective_balance(state, validator_index) >= MAX_DEPOSIT_AMOUNT: activate_validator(state, validator_index, True) + state.latest_index_roots[GENESIS_SLOT // EPOCH_LENGTH % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, GENESIS_SLOT)) + state.current_epoch_seed = generate_seed(state, GENESIS_SLOT) + return state ``` @@ -1568,6 +1593,8 @@ The steps below happen when `state.slot % EPOCH_LENGTH == EPOCH_LENGTH - 1`. * Let `next_epoch_start_slot = state.slot + 1`. * Let `current_epoch_start_slot = state.slot - (EPOCH_LENGTH + 1)`. * Let `previous_epoch_start_slot = state.slot - 2 * EPOCH_LENGTH + 1` if `state.slot > EPOCH_LENGTH` else `current_epoch_start_slot`. +* Let `next_epoch = next_epoch_start_slot // EPOCH_LENGTH`. +* Let `current_epoch = current_epoch_start_slot // EPOCH_LENGTH`. All [validators](#dfn-validator): @@ -1576,7 +1603,7 @@ All [validators](#dfn-validator): [Validators](#dfn-Validator) attesting during the current epoch: -* Let `current_epoch_attestations = [a for a in state.latest_attestations if current_epoch_start_slot <= a.data.slot <= state.slot]`. (Note: this is the set of attestations of slots in the epoch `current_epoch_start_slot...state.slot`, _not_ attestations that got included in the chain during the epoch `current_epoch_start_slot...state.slot`.) +* Let `current_epoch_attestations = [a for a in state.latest_attestations if current_epoch_start_slot <= a.data.slot < next_epoch_start_slot]`. (Note: this is the set of attestations of slots in the epoch `current_epoch_start_slot...next_epoch_start_slot`, _not_ attestations that got included in the chain during the epoch `current_epoch_start_slot...next_epoch_start_slot`.) * Validators justifying the epoch boundary block at the start of the current epoch: * Let `current_epoch_boundary_attestations = [a for a in current_epoch_attestations if a.data.epoch_boundary_root == get_block_root(state, current_epoch_start_slot) and a.data.justified_slot == state.justified_slot]`. * Let `current_epoch_boundary_attester_indices` be the union of the [validator](#dfn-validator) index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in current_epoch_boundary_attestations]`. @@ -1719,7 +1746,7 @@ First, update the following: * Set `state.previous_epoch_calculation_slot = state.current_epoch_calculation_slot` * Set `state.previous_epoch_start_shard = state.current_epoch_start_shard` * Set `state.previous_epoch_seed = state.current_epoch_seed` -* Set `state.latest_index_roots[epoch % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, state.slot))` +* Set `state.latest_index_roots[next_epoch % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, next_epoch_start_slot))` If the following are satisfied: @@ -1769,21 +1796,21 @@ def update_validator_registry(state: BeaconState) -> None: # Exit validator exit_validator(state, index) - state.validator_registry_update_slot = state.slot + state.validator_registry_update_slot = state.slot - (state.slot % EPOCH_LENGTH) ``` and perform the following updates: -* Set `state.current_epoch_calculation_slot = state.slot` +* Set `state.current_epoch_calculation_slot = next_epoch_start_slot` * Set `state.current_epoch_start_shard = (state.current_epoch_start_shard + get_current_epoch_committee_count_per_slot(state) * EPOCH_LENGTH) % SHARD_COUNT` -* Set `state.current_epoch_seed = hash(get_randao_mix(state, state.current_epoch_calculation_slot - SEED_LOOKAHEAD) + get_active_index_root(state, state.current_epoch_calculation_slot))` +* Set `state.current_epoch_seed = generate_seed(state, state.current_epoch_calculation_slot)` If a validator registry update does _not_ happen do the following: -* Let `epochs_since_last_registry_change = (state.slot - state.validator_registry_update_slot) // EPOCH_LENGTH`. +* Let `epochs_since_last_registry_change = (current_epoch_start_slot - state.validator_registry_update_slot) // EPOCH_LENGTH`. * If `epochs_since_last_registry_change` is an exact power of 2: - * Set `state.current_epoch_calculation_slot = state.slot`. - * Set `state.current_epoch_seed = hash(get_randao_mix(state, state.current_epoch_calculation_slot - SEED_LOOKAHEAD) + get_active_index_root(state, state.current_epoch_calculation_slot))`. + * Set `state.current_epoch_calculation_slot = next_epoch_start_slot`. + * Set `state.current_epoch_seed = generate_seed(state, state.current_epoch_calculation_slot)` * _Note_ that `state.current_epoch_start_shard` is left unchanged. **Invariant**: the active index root that is hashed into the shuffling seed actually is the `hash_tree_root` of the validator set that is used for that epoch. @@ -1827,8 +1854,7 @@ def process_penalties_and_exits(state: BeaconState) -> None: ### Final updates -* Let `epoch = state.slot // EPOCH_LENGTH`. -* Set `state.latest_penalized_balances[(epoch+1) % LATEST_PENALIZED_EXIT_LENGTH] = state.latest_penalized_balances[epoch % LATEST_PENALIZED_EXIT_LENGTH]`. +* Set `state.latest_penalized_balances[(next_epoch) % LATEST_PENALIZED_EXIT_LENGTH] = state.latest_penalized_balances[current_epoch % LATEST_PENALIZED_EXIT_LENGTH]`. * Remove any `attestation` in `state.latest_attestations` such that `attestation.data.slot < current_epoch_start_slot`. ## State root processing From 6f830179c6b397823b0aa4776a64620b65e35f67 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Fri, 25 Jan 2019 16:50:15 -0700 Subject: [PATCH 24/70] remove extra blank line --- specs/core/0_beacon-chain.md | 1 - 1 file changed, 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index f924d2dc7..ed0ecf444 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1019,7 +1019,6 @@ def generate_seed(state: BeaconState, ``` - #### `get_beacon_proposer_index` ```python From e34cfc8de8f9663a9431dcda3ca52c87bf190321 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Fri, 25 Jan 2019 17:26:27 -0700 Subject: [PATCH 25/70] fix preivous_epoch_start_slot to be based upon GENESIS_SLOT --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index ed0ecf444..20879dd41 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1591,7 +1591,7 @@ The steps below happen when `state.slot % EPOCH_LENGTH == EPOCH_LENGTH - 1`. * Let `next_epoch_start_slot = state.slot + 1`. * Let `current_epoch_start_slot = state.slot - (EPOCH_LENGTH + 1)`. -* Let `previous_epoch_start_slot = state.slot - 2 * EPOCH_LENGTH + 1` if `state.slot > EPOCH_LENGTH` else `current_epoch_start_slot`. +* Let `previous_epoch_start_slot = state.slot - 2 * EPOCH_LENGTH + 1` if `state.slot > GENESIS_SLOT + EPOCH_LENGTH` else `current_epoch_start_slot`. * Let `next_epoch = next_epoch_start_slot // EPOCH_LENGTH`. * Let `current_epoch = current_epoch_start_slot // EPOCH_LENGTH`. From a212038cd3c37a05fc99fb6da48a2c10678993b1 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Fri, 25 Jan 2019 17:33:15 -0700 Subject: [PATCH 26/70] begin translation to epochs --- specs/core/0_beacon-chain.md | 200 ++++++++++++++++++----------------- 1 file changed, 103 insertions(+), 97 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index ed0ecf444..0f283103b 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -60,6 +60,7 @@ - [Helper functions](#helper-functions) - [`hash`](#hash) - [`hash_tree_root`](#hash_tree_root) + - [`slot_to_epoch`](#slot_to_epoch) - [`is_active_validator`](#is_active_validator) - [`get_active_validator_indices`](#get_active_validator_indices) - [`shuffle`](#shuffle) @@ -84,7 +85,7 @@ - [`is_double_vote`](#is_double_vote) - [`is_surround_vote`](#is_surround_vote) - [`integer_squareroot`](#integer_squareroot) - - [`entry_exit_effect_slot`](#entry_exit_effect_slot) + - [`entry_exit_effect_epoch`](#entry_exit_effect_epoch) - [`bls_verify`](#bls_verify) - [`bls_verify_multiple`](#bls_verify_multiple) - [`bls_aggregate_pubkeys`](#bls_aggregate_pubkeys) @@ -191,7 +192,7 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `GENESIS_FORK_VERSION` | `0` | | `GENESIS_SLOT` | `0` | | `GENESIS_START_SHARD` | `0` | -| `FAR_FUTURE_SLOT` | `2**64 - 1` | +| `FAR_FUTURE_EPOCH` | `2**64 - 1` | | `ZERO_HASH` | `int_to_bytes32(0)` | | `EMPTY_SIGNATURE` | `int_to_bytes96(0)` | | `BLS_WITHDRAWAL_PREFIX_BYTE` | `int_to_bytes1(0)` | @@ -203,10 +204,10 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `SLOT_DURATION` | `6` | seconds | 6 seconds | | `MIN_ATTESTATION_INCLUSION_DELAY` | `2**2` (= 4) | slots | 24 seconds | | `EPOCH_LENGTH` | `2**6` (= 64) | slots | 6.4 minutes | -| `SEED_LOOKAHEAD` | `2**6` (= 64) | slots | 6.4 minutes | -| `ENTRY_EXIT_DELAY` | `2**8` (= 256) | slots | 25.6 minutes | +| `SEED_LOOKAHEAD` | `2**0` (= 1) | epochs | 6.4 minutes | +| `ENTRY_EXIT_DELAY` | `2**2` (= 4) | epochs | 25.6 minutes | | `ETH1_DATA_VOTING_PERIOD` | `2**10` (= 1,024) | slots | ~1.7 hours | -| `MIN_VALIDATOR_WITHDRAWAL_TIME` | `2**14` (= 16,384) | slots | ~27 hours | +| `MIN_VALIDATOR_WITHDRAWAL_EPOCHS` | `2**8` (= 256) | epochs | ~27 hours | ### Reward and penalty quotients @@ -468,7 +469,7 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be # Validator registry 'validator_registry': [Validator], 'validator_balances': ['uint64'], - 'validator_registry_update_slot': 'uint64', + 'validator_registry_update_epoch': 'uint64', 'validator_registry_exit_count': 'uint64', # Randomness and committees @@ -476,8 +477,8 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'latest_vdf_outputs': ['bytes32'], 'previous_epoch_start_shard': 'uint64', 'current_epoch_start_shard': 'uint64', - 'previous_epoch_calculation_slot': 'uint64', - 'current_epoch_calculation_slot': 'uint64', + 'previous_calculation_epoch': 'uint64', + 'current_calculation_epoch': 'uint64', 'previous_epoch_seed': 'bytes32', 'current_epoch_seed': 'bytes32', @@ -514,14 +515,14 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'withdrawal_credentials': 'bytes32', # Number of proposer slots since genesis 'proposer_slots': 'uint64', - # Slot when validator activated - 'activation_slot': 'uint64', - # Slot when validator exited - 'exit_slot': 'uint64', - # Slot when validator withdrew - 'withdrawal_slot': 'uint64', - # Slot when validator was penalized - 'penalized_slot': 'uint64', + # Epoch when validator activated + 'activation_epoch': 'uint64', + # Epoch when validator exited + 'exit_epoch': 'uint64', + # Epoch when validator withdrew + 'withdrawal_epoch': 'uint64', + # Epoch when validator was penalized + 'penalized_epoch': 'uint64', # Exit counter when validator exited 'exit_count': 'uint64', # Status flags @@ -762,13 +763,20 @@ Note: We aim to migrate to a S[T/N]ARK-friendly hash function in a future Ethere `hash_tree_root` is a function for hashing objects into a single root utilizing a hash tree structure. `hash_tree_root` is defined in the [SimpleSerialize spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/simple-serialize.md#tree-hash). +#### `slot_to_epoch` + +```python +def slot_to_epoch(slot: int) -> int: + return slot // EPOCH_LENGTH +``` + #### `is_active_validator` ```python def is_active_validator(validator: Validator, slot: int) -> bool: """ Checks if ``validator`` is active. """ - return validator.activation_slot <= slot < validator.exit_slot + return validator.activation_epoch <= slot_to_epoch(slot) < validator.exit_epoch ``` #### `get_active_validator_indices` @@ -866,29 +874,26 @@ def get_committee_count_per_slot(active_validator_count: int) -> int: ```python def get_shuffling(seed: Bytes32, validators: List[Validator], - slot: int) -> List[List[int]] + epoch: int) -> List[List[int]] """ - Shuffles ``validators`` into crosslink committees seeded by ``seed`` and ``slot``. + Shuffles ``validators`` into crosslink committees seeded by ``seed`` and ``epoch``. Returns a list of ``EPOCH_LENGTH * committees_per_slot`` committees where each committee is itself a list of validator indices. """ - # Normalizes slot to start of epoch boundary - slot -= slot % EPOCH_LENGTH - active_validator_indices = get_active_validator_indices(validators, slot) committees_per_slot = get_committee_count_per_slot(len(active_validator_indices)) # Shuffle - seed = xor(seed, int_to_bytes32(slot)) + seed = xor(seed, int_to_bytes32(epoch)) shuffled_active_validator_indices = shuffle(active_validator_indices, seed) # Split the shuffled list into epoch_length * committees_per_slot pieces return split(shuffled_active_validator_indices, committees_per_slot * EPOCH_LENGTH) ``` -**Invariant**: if `get_shuffling(seed, validators, slot)` returns some value `x` for some `slot <= state.slot + ENTRY_EXIT_DELAY`, it should return the same value `x` for the same `seed` and `slot` and possible future modifications of `validators` forever in phase 0, and until the ~1 year deletion delay in phase 2 and in the future. +**Invariant**: if `get_shuffling(seed, validators, epoch)` returns some value `x` for some `epoch <= slot_to_epoch(state.slot) + ENTRY_EXIT_DELAY`, it should return the same value `x` for the same `seed` and `epoch` and possible future modifications of `validators` forever in phase 0, and until the ~1 year deletion delay in phase 2 and in the future. **Note**: this definition and the next few definitions make heavy use of repetitive computing. Production implementations are expected to appropriately use caching/memoization to avoid redoing work. @@ -898,7 +903,7 @@ def get_shuffling(seed: Bytes32, def get_previous_epoch_committee_count_per_slot(state: BeaconState) -> int: previous_active_validators = get_active_validator_indices( state.validator_registry, - state.previous_epoch_calculation_slot, + state.previous_calculation_epoch, ) return get_committee_count_per_slot(len(previous_active_validators)) ``` @@ -909,7 +914,7 @@ def get_previous_epoch_committee_count_per_slot(state: BeaconState) -> int: def get_current_epoch_committee_count_per_slot(state: BeaconState) -> int: current_active_validators = get_active_validator_indices( state.validator_registry, - state.current_epoch_calculation_slot, + state.current_calculation_epoch, ) return get_committee_count_per_slot(len(current_active_validators)) ``` @@ -929,18 +934,18 @@ def get_crosslink_committees_at_slot(state: BeaconState, if slot < state_epoch_slot: committees_per_slot = get_previous_epoch_committee_count_per_slot(state) seed = state.previous_epoch_seed - shuffling_slot = state.previous_epoch_calculation_slot + shuffling_epoch = state.previous_calculation_epoch shuffling_start_shard = state.previous_epoch_start_shard else: committees_per_slot = get_current_epoch_committee_count_per_slot(state) seed = state.current_epoch_seed - shuffling_slot = state.current_epoch_calculation_slot + shuffling_epoch = state.current_calculation_epoch shuffling_start_shard = state.current_epoch_start_shard shuffling = get_shuffling( seed, state.validator_registry, - shuffling_slot, + shuffling_epoch, ) offset = slot % EPOCH_LENGTH slot_start_shard = (shuffling_start_shard + committees_per_slot * offset) % SHARD_COUNT @@ -988,33 +993,32 @@ def get_randao_mix(state: BeaconState, ```python def get_active_index_root(state: BeaconState, - slot: int) -> Bytes32: + epoch: int) -> Bytes32: """ Returns the index root at a recent ``slot``. """ - state_epoch = state.slot // EPOCH_LENGTH - given_epoch = slot // EPOCH_LENGTH - assert state_epoch < given_epoch + LATEST_INDEX_ROOTS_LENGTH - assert given_epoch <= state_epoch - return state.latest_index_roots[given_epoch % LATEST_INDEX_ROOTS_LENGTH] + state_epoch = slot_to_epoch(state.slot) + assert state_epoch < epoch + LATEST_INDEX_ROOTS_LENGTH + assert epoch <= state_epoch + return state.latest_index_roots[epoch % LATEST_INDEX_ROOTS_LENGTH] ``` #### `generate_seed` ```python def generate_seed(state: BeaconState, - slot: int) -> Bytes32: + epoch: int) -> Bytes32: """ - Generate a seed for the given ``slot``. + Generate a seed for the given ``epoch``. """ - if slot < SEED_LOOKAHEAD: - randao_mix_slot = GENESIS_SLOT + if epoch < SEED_LOOKAHEAD: + randao_mix_epoch = slot_to_epoch(GENESIS_SLOT) else: - randao_mix_slot = slot - SEED_LOOKAHEAD + randao_mix_epoch = epoch - SEED_LOOKAHEAD return hash( - get_randao_mix(state, randao_mix_slot) + - get_active_index_root(state, slot) + get_randao_mix(state, randao_mix_epoch * EPOCH_LENGTH) + + get_active_index_root(state, epoch) ) ``` @@ -1142,8 +1146,8 @@ def is_double_vote(attestation_data_1: AttestationData, Returns True if the provided ``AttestationData`` are slashable due to a 'double vote'. """ - target_epoch_1 = attestation_data_1.slot // EPOCH_LENGTH - target_epoch_2 = attestation_data_2.slot // EPOCH_LENGTH + target_epoch_1 = slot_to_epoch(attestation_data_1.slot) + target_epoch_2 = slot_to_epoch(attestation_data_2.slot) return target_epoch_1 == target_epoch_2 ``` @@ -1159,10 +1163,10 @@ def is_surround_vote(attestation_data_1: AttestationData, Note: parameter order matters as this function only checks that ``attestation_data_1`` surrounds ``attestation_data_2``. """ - source_epoch_1 = attestation_data_1.justified_slot // EPOCH_LENGTH - source_epoch_2 = attestation_data_2.justified_slot // EPOCH_LENGTH - target_epoch_1 = attestation_data_1.slot // EPOCH_LENGTH - target_epoch_2 = attestation_data_2.slot // EPOCH_LENGTH + source_epoch_1 = slot_to_epoch(attestation_data_1.justified_slot) + source_epoch_2 = slot_to_epoch(attestation_data_2.justified_slot) + target_epoch_1 = slot_to_epoch(attestation_data_1.slot) + target_epoch_2 = slot_to_epoch(attestation_data_2.slot) return ( (source_epoch_1 < source_epoch_2) and (source_epoch_2 + 1 == target_epoch_2) and @@ -1186,15 +1190,15 @@ def integer_squareroot(n: int) -> int: return x ``` -#### `entry_exit_effect_slot` +#### `entry_exit_effect_epoch` ```python -def entry_exit_effect_slot(n: int) -> int: +def entry_exit_effect_epoch(slot: int) -> int: """ An entry or exit triggered in the slot given by the input takes effect at - the slot given by the output. + the epoch given by the output. """ - return (n - n % EPOCH_LENGTH) + EPOCH_LENGTH + ENTRY_EXIT_DELAY + return slot_to_epoch(slot) + 1 + ENTRY_EXIT_DELAY ``` #### `bls_verify` @@ -1256,7 +1260,7 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], # Validator registry validator_registry=[], validator_balances=[], - validator_registry_update_slot=GENESIS_SLOT, + validator_registry_update_epoch=slot_to_epoch(GENESIS_SLOT), validator_registry_exit_count=0, # Randomness and committees @@ -1264,8 +1268,8 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], latest_vdf_outputs=[ZERO_HASH for _ in range(LATEST_RANDAO_MIXES_LENGTH // EPOCH_LENGTH)], previous_epoch_start_shard=GENESIS_START_SHARD, current_epoch_start_shard=GENESIS_START_SHARD, - previous_epoch_calculation_slot=GENESIS_SLOT, - current_epoch_calculation_slot=GENESIS_SLOT, + previous_calculation_epoch=slot_to_epoch(GENESIS_SLOT), + current_calculation_epoch=slot_to_epoch(GENESIS_SLOT), previous_epoch_seed=ZERO_HASH, current_epoch_seed=ZERO_HASH, @@ -1306,8 +1310,9 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], if get_effective_balance(state, validator_index) >= MAX_DEPOSIT_AMOUNT: activate_validator(state, validator_index, True) - state.latest_index_roots[GENESIS_SLOT // EPOCH_LENGTH % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, GENESIS_SLOT)) - state.current_epoch_seed = generate_seed(state, GENESIS_SLOT) + genesis_epoch = slot_to_epoch(GENESIS_SLOT) + state.latest_index_roots[genesis_epoch % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, genesis_epoch)) + state.current_epoch_seed = generate_seed(state, genesis_epoch) return state ``` @@ -1367,10 +1372,10 @@ def process_deposit(state: BeaconState, pubkey=pubkey, withdrawal_credentials=withdrawal_credentials, proposer_slots=0, - activation_slot=FAR_FUTURE_SLOT, - exit_slot=FAR_FUTURE_SLOT, - withdrawal_slot=FAR_FUTURE_SLOT, - penalized_slot=FAR_FUTURE_SLOT, + activation_epoch=FAR_FUTURE_EPOCH, + exit_epch=FAR_FUTURE_EPOCH, + withdrawal_epoch=FAR_FUTURE_EPOCH, + penalized_epoch=FAR_FUTURE_EPOCH, exit_count=0, status_flags=0, latest_custody_reseed_slot=GENESIS_SLOT, @@ -1396,7 +1401,7 @@ Note: All functions in this section mutate `state`. def activate_validator(state: BeaconState, index: int, genesis: bool) -> None: validator = state.validator_registry[index] - validator.activation_slot = GENESIS_SLOT if genesis else entry_exit_effect_slot(state.slot) + validator.activation_epoch = slot_to_epoch(GENESIS_SLOT) if genesis else entry_exit_effect_epoch(state.slot) ``` ```python @@ -1410,10 +1415,10 @@ def exit_validator(state: BeaconState, index: int) -> None: validator = state.validator_registry[index] # The following updates only occur if not previous exited - if validator.exit_slot <= entry_exit_effect_slot(state.slot): + if validator.exit_epoch <= entry_exit_effect_epoch(state.slot): return - validator.exit_slot = entry_exit_effect_slot(state.slot) + validator.exit_epoch = entry_exit_effect_epoch(state.slot) state.validator_registry_exit_count += 1 validator.exit_count = state.validator_registry_exit_count @@ -1423,13 +1428,13 @@ def exit_validator(state: BeaconState, index: int) -> None: def penalize_validator(state: BeaconState, index: int) -> None: exit_validator(state, index) validator = state.validator_registry[index] - state.latest_penalized_balances[(state.slot // EPOCH_LENGTH) % LATEST_PENALIZED_EXIT_LENGTH] += get_effective_balance(state, index) + state.latest_penalized_balances[slot_to_epoch(state.slot) % LATEST_PENALIZED_EXIT_LENGTH] += get_effective_balance(state, index) whistleblower_index = get_beacon_proposer_index(state, state.slot) whistleblower_reward = get_effective_balance(state, index) // WHISTLEBLOWER_REWARD_QUOTIENT state.validator_balances[whistleblower_index] += whistleblower_reward state.validator_balances[index] -= whistleblower_reward - validator.penalized_slot = state.slot + validator.penalized_epoch = slot_to_epoch(state.slot) ``` ```python @@ -1573,7 +1578,7 @@ Verify that `len(block.body.exits) <= MAX_EXITS`. For each `exit` in `block.body.exits`: * Let `validator = state.validator_registry[exit.validator_index]`. -* Verify that `validator.exit_slot > entry_exit_effect_slot(state.slot)`. +* Verify that `validator.exit_epoch > entry_exit_effect_epoch(state.slot)`. * Verify that `state.slot >= exit.slot`. * Let `exit_message = hash_tree_root(Exit(slot=exit.slot, validator_index=exit.validator_index, signature=EMPTY_SIGNATURE))`. * Verify that `bls_verify(pubkey=validator.pubkey, message=exit_message, signature=exit.signature, domain=get_domain(state.fork, exit.slot, DOMAIN_EXIT))`. @@ -1589,15 +1594,16 @@ The steps below happen when `state.slot % EPOCH_LENGTH == EPOCH_LENGTH - 1`. ### Helpers -* Let `next_epoch_start_slot = state.slot + 1`. -* Let `current_epoch_start_slot = state.slot - (EPOCH_LENGTH + 1)`. -* Let `previous_epoch_start_slot = state.slot - 2 * EPOCH_LENGTH + 1` if `state.slot > EPOCH_LENGTH` else `current_epoch_start_slot`. -* Let `next_epoch = next_epoch_start_slot // EPOCH_LENGTH`. -* Let `current_epoch = current_epoch_start_slot // EPOCH_LENGTH`. +* Let `current_epoch = slot_to_epoch(state.slot)`. +* Let `current_epoch_start_slot = current_epoch * EPOCH_LENGTH`. +* Let `next_epoch = slot_to_epoch(state.slot + 1)`. +* Let `next_epoch_start_slot = next_epoch * EPOCH_LENGTH`. +* Let `previous_epoch = current_epoch - 1 if current_epoch > slot_to_epoch(GENESIS_SLOT) else current_epoch`. +* Let `previous_epoch_start_slot = previous_epoch * EPOCH_LENGTH`. All [validators](#dfn-validator): -* Let `active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch_start_slot)`. +* Let `active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch)`. * Let `total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices])`. [Validators](#dfn-Validator) attesting during the current epoch: @@ -1688,7 +1694,7 @@ First, we define some additional helpers: Note: When applying penalties in the following balance recalculations implementers should make sure the `uint64` does not underflow. -* Let `epochs_since_finality = (next_epoch_start_slot - state.finalized_slot) // EPOCH_LENGTH`. +* Let `epochs_since_finality = next_epoch - slot_to_epoch(state.finalized_slot)`. Case 1: `epochs_since_finality <= 4`: @@ -1709,7 +1715,7 @@ Case 2: `epochs_since_finality > 4`: * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_justified_attester_indices`, loses `inactivity_penalty(state, index, epochs_since_finality)`. * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_boundary_attester_indices`, loses `inactivity_penalty(state, index, epochs_since_finality)`. * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_head_attester_indices`, loses `base_reward(state, index)`. -* Any [active_validator](#dfn-active-validator) `index` with `validator.penalized_slot <= current_epoch_start_slot`, loses `2 * inactivity_penalty(state, index, epochs_since_finality) + base_reward(state, index)`. +* Any [active_validator](#dfn-active-validator) `index` with `validator.penalized_epoch <= current_epoch`, loses `2 * inactivity_penalty(state, index, epochs_since_finality) + base_reward(state, index)`. * Any [validator](#dfn-validator) `index` in `previous_epoch_attester_indices` loses `base_reward(state, index) - base_reward(state, index) * MIN_ATTESTATION_INCLUSION_DELAY // inclusion_distance(state, index)` #### Attestation inclusion @@ -1733,7 +1739,7 @@ def process_ejections(state: BeaconState) -> None: Iterate through the validator registry and eject active validators with balance below ``EJECTION_BALANCE``. """ - for index in get_active_validator_indices(state.validator_registry, current_epoch_start_slot): + for index in get_active_validator_indices(state.validator_registry, current_epoch): if state.validator_balances[index] < EJECTION_BALANCE: exit_validator(state, index) ``` @@ -1742,15 +1748,15 @@ def process_ejections(state: BeaconState) -> None: First, update the following: -* Set `state.previous_epoch_calculation_slot = state.current_epoch_calculation_slot` -* Set `state.previous_epoch_start_shard = state.current_epoch_start_shard` -* Set `state.previous_epoch_seed = state.current_epoch_seed` -* Set `state.latest_index_roots[next_epoch % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, next_epoch_start_slot))` +* Set `state.previous_calculation_epoch = state.current_calculation_epoch`. +* Set `state.previous_epoch_start_shard = state.current_epoch_start_shard`. +* Set `state.previous_epoch_seed = state.current_epoch_seed`. +* Set `state.latest_index_roots[next_epoch % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, next_epoch_start_slot))`. If the following are satisfied: -* `state.finalized_slot > state.validator_registry_update_slot` -* `state.latest_crosslinks[shard].slot > state.validator_registry_update_slot` for every shard number `shard` in `[(state.current_epoch_start_shard + i) % SHARD_COUNT for i in range(get_current_epoch_committee_count_per_slot(state) * EPOCH_LENGTH)]` (that is, for every shard in the current committees) +* `slot_to_epoch(state.finalized_slot) > state.validator_registry_update_epoch` +* `slot_to_epoch(state.latest_crosslinks[shard].slot) > state.validator_registry_update_epoch` for every shard number `shard` in `[(state.current_epoch_start_shard + i) % SHARD_COUNT for i in range(get_current_epoch_committee_count_per_slot(state) * EPOCH_LENGTH)]` (that is, for every shard in the current committees) update the validator registry and associated fields by running @@ -1761,7 +1767,7 @@ def update_validator_registry(state: BeaconState) -> None: Note that this function mutates ``state``. """ # The active validators - active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch_start_slot) + active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch) # The total effective balance of active validators total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices]) @@ -1774,7 +1780,7 @@ def update_validator_registry(state: BeaconState) -> None: # Activate validators within the allowable balance churn balance_churn = 0 for index, validator in enumerate(state.validator_registry): - if validator.activation_slot > entry_exit_effect_slot(state.slot) and state.validator_balances[index] >= MAX_DEPOSIT_AMOUNT: + if validator.activation_epoch > entry_exit_effect_epoch(state.slot) and state.validator_balances[index] >= MAX_DEPOSIT_AMOUNT: # Check the balance churn would be within the allowance balance_churn += get_effective_balance(state, index) if balance_churn > max_balance_churn: @@ -1786,7 +1792,7 @@ def update_validator_registry(state: BeaconState) -> None: # Exit validators within the allowable balance churn balance_churn = 0 for index, validator in enumerate(state.validator_registry): - if validator.exit_slot > entry_exit_effect_slot(state.slot) and validator.status_flags & INITIATED_EXIT: + if validator.exit_epoch > entry_exit_effect_epoch(state.slot) and validator.status_flags & INITIATED_EXIT: # Check the balance churn would be within the allowance balance_churn += get_effective_balance(state, index) if balance_churn > max_balance_churn: @@ -1795,21 +1801,21 @@ def update_validator_registry(state: BeaconState) -> None: # Exit validator exit_validator(state, index) - state.validator_registry_update_slot = state.slot - (state.slot % EPOCH_LENGTH) + state.validator_registry_update_epoch = slot_to_epoch(state.slot) ``` and perform the following updates: -* Set `state.current_epoch_calculation_slot = next_epoch_start_slot` +* Set `state.current_calculation_epoch = next_epoch` * Set `state.current_epoch_start_shard = (state.current_epoch_start_shard + get_current_epoch_committee_count_per_slot(state) * EPOCH_LENGTH) % SHARD_COUNT` -* Set `state.current_epoch_seed = generate_seed(state, state.current_epoch_calculation_slot)` +* Set `state.current_epoch_seed = generate_seed(state, state.current_calculation_epoch)` If a validator registry update does _not_ happen do the following: -* Let `epochs_since_last_registry_change = (current_epoch_start_slot - state.validator_registry_update_slot) // EPOCH_LENGTH`. +* Let `epochs_since_last_registry_change = (current_epoch - state.validator_registry_update_epoch)`. * If `epochs_since_last_registry_change` is an exact power of 2: - * Set `state.current_epoch_calculation_slot = next_epoch_start_slot`. - * Set `state.current_epoch_seed = generate_seed(state, state.current_epoch_calculation_slot)` + * Set `state.current_calculation_epoch = next_epoch`. + * Set `state.current_epoch_seed = generate_seed(state, state.current_calculation_epoch)` * _Note_ that `state.current_epoch_start_shard` is left unchanged. **Invariant**: the active index root that is hashed into the shuffling seed actually is the `hash_tree_root` of the validator set that is used for that epoch. @@ -1824,8 +1830,8 @@ def process_penalties_and_exits(state: BeaconState) -> None: total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices]) for index, validator in enumerate(state.validator_registry): - if (state.slot // EPOCH_LENGTH) == (validator.penalized_slot // EPOCH_LENGTH) + LATEST_PENALIZED_EXIT_LENGTH // 2: - e = (state.slot // EPOCH_LENGTH) % LATEST_PENALIZED_EXIT_LENGTH + if slot_to_epoch(state.slot) == validator.penalized_epoch + LATEST_PENALIZED_EXIT_LENGTH // 2: + e = slot_to_epoch(state.slot) % LATEST_PENALIZED_EXIT_LENGTH total_at_start = state.latest_penalized_balances[(e + 1) % LATEST_PENALIZED_EXIT_LENGTH] total_at_end = state.latest_penalized_balances[e] total_penalties = total_at_end - total_at_start @@ -1834,11 +1840,11 @@ def process_penalties_and_exits(state: BeaconState) -> None: def eligible(index): validator = state.validator_registry[index] - if validator.penalized_slot <= state.slot: - PENALIZED_WITHDRAWAL_TIME = LATEST_PENALIZED_EXIT_LENGTH * EPOCH_LENGTH // 2 - return state.slot >= validator.penalized_slot + PENALIZED_WITHDRAWAL_TIME + if validator.penalized_epoch <= slot_to_epoch(state.slot): + PENALIZED_WITHDRAWAL_EPOCHS = LATEST_PENALIZED_EXIT_LENGTH // 2 + return slot_to_epoch(state.slot) >= validator.penalized_epoch + PENALIZED_WITHDRAWAL_EPOCHS else: - return state.slot >= validator.exit_slot + MIN_VALIDATOR_WITHDRAWAL_TIME + return slot_to_epoch(state.slot) >= validator.exit_epoch + MIN_VALIDATOR_WITHDRAWAL_EPOCHS all_indices = list(range(len(state.validator_registry))) eligible_indices = filter(eligible, all_indices) From f943361a23883b387cd52c00bea24d7605fccc5b Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Fri, 25 Jan 2019 17:40:44 -0700 Subject: [PATCH 27/70] convert voting period to epochs --- specs/core/0_beacon-chain.md | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 0f283103b..372191e8f 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -206,7 +206,7 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `EPOCH_LENGTH` | `2**6` (= 64) | slots | 6.4 minutes | | `SEED_LOOKAHEAD` | `2**0` (= 1) | epochs | 6.4 minutes | | `ENTRY_EXIT_DELAY` | `2**2` (= 4) | epochs | 25.6 minutes | -| `ETH1_DATA_VOTING_PERIOD` | `2**10` (= 1,024) | slots | ~1.7 hours | +| `ETH1_DATA_VOTING_PERIOD` | `2**4` (= 16) | epochs | ~1.7 hours | | `MIN_VALIDATOR_WITHDRAWAL_EPOCHS` | `2**8` (= 256) | epochs | ~27 hours | ### Reward and penalty quotients @@ -1590,7 +1590,7 @@ For each `exit` in `block.body.exits`: ## Per-epoch processing -The steps below happen when `state.slot % EPOCH_LENGTH == EPOCH_LENGTH - 1`. +The steps below happen when `(state.slot + 1) % EPOCH_LENGTH == 0`. ### Helpers @@ -1650,9 +1650,9 @@ Define the following helpers to process attestation inclusion rewards and inclus ### Eth1 data -If `state.slot % ETH1_DATA_VOTING_PERIOD == ETH1_DATA_VOTING_PERIOD - 1`: +If `slot_to_epoch(state.slot) % ETH1_DATA_VOTING_PERIOD == 0`: -* Set `state.latest_eth1_data = eth1_data_vote.data` if `eth1_data_vote.vote_count * 2 > ETH1_DATA_VOTING_PERIOD` for some `eth1_data_vote` in `state.eth1_data_votes`. +* Set `state.latest_eth1_data = eth1_data_vote.data` if `eth1_data_vote.vote_count * 2 > ETH1_DATA_VOTING_PERIOD * EPOCH_LENGTH` for some `eth1_data_vote` in `state.eth1_data_votes`. * Set `state.eth1_data_votes = []`. ### Justification @@ -1812,7 +1812,7 @@ and perform the following updates: If a validator registry update does _not_ happen do the following: -* Let `epochs_since_last_registry_change = (current_epoch - state.validator_registry_update_epoch)`. +* Let `epochs_since_last_registry_change = current_epoch - state.validator_registry_update_epoch`. * If `epochs_since_last_registry_change` is an exact power of 2: * Set `state.current_calculation_epoch = next_epoch`. * Set `state.current_epoch_seed = generate_seed(state, state.current_calculation_epoch)` From feaf689c9401434b97cd2f68b22baaae74368861 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sat, 26 Jan 2019 16:02:49 +0800 Subject: [PATCH 28/70] Apply suggestions from code review Co-Authored-By: hwwhww --- specs/core/0_beacon-chain.md | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index a4440e924..ea2d6eeb0 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -622,11 +622,11 @@ We define the following Python custom types for type hinting and readability: | - | - | - | | `SlotNumber` | unsigned 64-bit integer | the number of a slot | | `ShardNumber` | unsigned 64-bit integer | the number of a shard | -| `ValidatorIndex` | unsigned 24-bit integer | the index number of validator in the registry | -| `Gwei` | unsigned 64-bit integer | the amount in Gwei | -| `Bytes32` | 32-byte data | the binary data in 32-byte length | -| `BLSPubkey` | 48-byte data | the public key in BLS signature scheme | -| `BLSSignature` | 96-byte data | the signature in BLS signature scheme | +| `ValidatorIndex` | unsigned 24-bit integer | the index number of a validator in the registry | +| `Gwei` | unsigned 64-bit integer | an amount in Gwei | +| `Bytes32` | 32-byte data | binary data with 32-byte length | +| `BLSPubkey` | 48-byte data | a public key in BLS signature scheme | +| `BLSSignature` | 96-byte data | a signature in BLS signature scheme | ## Ethereum 1.0 deposit contract @@ -746,14 +746,14 @@ Beacon block production is significantly different because of the proof of stake The beacon chain fork choice rule is a hybrid that combines justification and finality with Latest Message Driven (LMD) Greediest Heaviest Observed SubTree (GHOST). At any point in time a [validator](#dfn-validator) `v` subjectively calculates the beacon chain head as follows. -* Abstractly define `Store` as the type of storage object for the chain data and `store` be the set of attestations and blocks that the [validator](#dfn-validator) `v` has observed and verified (in particular, block ancestors must be recursively verified). Attestations not part of any chain are still included in `store`. +* Abstractly define `Store` as the type of storage object for the chain data and `store` be the set of attestations and blocks that the [validator](#dfn-validator) `v` has observed and verified (in particular, block ancestors must be recursively verified). Attestations not yet included in any chain are still included in `store`. * Let `finalized_head` be the finalized block with the highest slot number. (A block `B` is finalized if there is a descendant of `B` in `store` the processing of which sets `B` as finalized.) * Let `justified_head` be the descendant of `finalized_head` with the highest slot number that has been justified for at least `EPOCH_LENGTH` slots. (A block `B` is justified if there is a descendant of `B` in `store` the processing of which sets `B` as justified.) If no such descendant exists set `justified_head` to `finalized_head`. * Let `get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBlock` be the ancestor of `block` with slot number `slot`. The `get_ancestor` function can be defined recursively as `def get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBlock: return block if block.slot == slot else get_ancestor(store, store.get_parent(block), slot)`. * Let `get_latest_attestation(store: Store, validator: Validator) -> Attestation` be the attestation with the highest slot number in `store` from `validator`. If several such attestations exist, use the one the [validator](#dfn-validator) `v` observed first. * Let `get_latest_attestation_target(store: Store, validator: Validator) -> BeaconBlock` be the target block in the attestation `get_latest_attestation(store, validator)`. -* Let `get_children(store: Store, block: BeaconBlock) -> List[BeaconBlock]` returns the children blocks of the given `block`. -* Let `justified_head_state` be the `BeaconState` object after processing `justified_head`. +* Let `get_children(store: Store, block: BeaconBlock) -> List[BeaconBlock]` returns the child blocks of the given `block`. +* Let `justified_head_state` be the resulting `BeaconState` object from processing the chain up to the `justified_head`. * The `head` is `lmd_ghost(store, justified_head_state, justified_head)` where the function `lmd_ghost` is defined below. Note that the implementation below is suboptimal; there are implementations that compute the head in time logarithmic in slot count. ```python From 8c91be9e74c3ed5cc19695deb891cd72c08c0f8f Mon Sep 17 00:00:00 2001 From: Hsiao-Wei Wang Date: Sat, 26 Jan 2019 16:07:15 +0800 Subject: [PATCH 29/70] Add custom type hinting for `get_active_index_root` --- specs/core/0_beacon-chain.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 5013b9c95..af121905f 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -116,7 +116,7 @@ - [Attestation inclusion](#attestation-inclusion) - [Crosslinks](#crosslinks-1) - [Ejections](#ejections) - - [Validator registry](#validator-registry) + - [Validator registry and shuffling seed data](#validator-registry-and-shuffling-seed-data) - [Final updates](#final-updates) - [State root processing](#state-root-processing) - [References](#references) @@ -1013,7 +1013,7 @@ def get_randao_mix(state: BeaconState, ```python def get_active_index_root(state: BeaconState, - slot: int) -> Bytes32: + slot: SlotNumber) -> Bytes32: """ Returns the index root at a recent ``slot``. """ From 0b827a04476f0fef05276aebb153e6ec9a51765a Mon Sep 17 00:00:00 2001 From: Paul Hauner Date: Sat, 26 Jan 2019 21:38:27 +1100 Subject: [PATCH 30/70] Change `PENALIZED_WITHDRAWAL_TIME` variable It's not in the "Constants" list and it is assigned to. --- specs/core/0_beacon-chain.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index af121905f..c7bef5c25 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1823,8 +1823,8 @@ def process_penalties_and_exits(state: BeaconState) -> None: def eligible(index): validator = state.validator_registry[index] if validator.penalized_slot <= state.slot: - PENALIZED_WITHDRAWAL_TIME = LATEST_PENALIZED_EXIT_LENGTH * EPOCH_LENGTH // 2 - return state.slot >= validator.penalized_slot + PENALIZED_WITHDRAWAL_TIME + penalized_withdrawal_time = LATEST_PENALIZED_EXIT_LENGTH * EPOCH_LENGTH // 2 + return state.slot >= validator.penalized_slot + penalized_withdrawal_time else: return state.slot >= validator.exit_slot + MIN_VALIDATOR_WITHDRAWAL_TIME From 0e90dd8ad021735669c219281b94fb8e39ac0e06 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sat, 26 Jan 2019 07:31:09 -0700 Subject: [PATCH 31/70] add current_epoch helper --- specs/core/0_beacon-chain.md | 53 ++++++++++++++++++++---------------- 1 file changed, 30 insertions(+), 23 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 372191e8f..49b4d0077 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -61,6 +61,7 @@ - [`hash`](#hash) - [`hash_tree_root`](#hash_tree_root) - [`slot_to_epoch`](#slot_to_epoch) + - [`current_epoch`](#current_epoch) - [`is_active_validator`](#is_active_validator) - [`get_active_validator_indices`](#get_active_validator_indices) - [`shuffle`](#shuffle) @@ -770,6 +771,14 @@ def slot_to_epoch(slot: int) -> int: return slot // EPOCH_LENGTH ``` +#### `current_epoch` + +```python +def current_epoch(state: BeaconState) -> int: + return slot_to_epoch(state.slot) +``` + + #### `is_active_validator` ```python def is_active_validator(validator: Validator, slot: int) -> bool: @@ -893,7 +902,7 @@ def get_shuffling(seed: Bytes32, return split(shuffled_active_validator_indices, committees_per_slot * EPOCH_LENGTH) ``` -**Invariant**: if `get_shuffling(seed, validators, epoch)` returns some value `x` for some `epoch <= slot_to_epoch(state.slot) + ENTRY_EXIT_DELAY`, it should return the same value `x` for the same `seed` and `epoch` and possible future modifications of `validators` forever in phase 0, and until the ~1 year deletion delay in phase 2 and in the future. +**Invariant**: if `get_shuffling(seed, validators, epoch)` returns some value `x` for some `epoch <= current_epoch(state) + ENTRY_EXIT_DELAY`, it should return the same value `x` for the same `seed` and `epoch` and possible future modifications of `validators` forever in phase 0, and until the ~1 year deletion delay in phase 2 and in the future. **Note**: this definition and the next few definitions make heavy use of repetitive computing. Production implementations are expected to appropriately use caching/memoization to avoid redoing work. @@ -997,9 +1006,8 @@ def get_active_index_root(state: BeaconState, """ Returns the index root at a recent ``slot``. """ - state_epoch = slot_to_epoch(state.slot) - assert state_epoch < epoch + LATEST_INDEX_ROOTS_LENGTH - assert epoch <= state_epoch + assert current_epoch(state) < epoch + LATEST_INDEX_ROOTS_LENGTH + assert epoch <= current_epoch(state) return state.latest_index_roots[epoch % LATEST_INDEX_ROOTS_LENGTH] ``` @@ -1428,13 +1436,13 @@ def exit_validator(state: BeaconState, index: int) -> None: def penalize_validator(state: BeaconState, index: int) -> None: exit_validator(state, index) validator = state.validator_registry[index] - state.latest_penalized_balances[slot_to_epoch(state.slot) % LATEST_PENALIZED_EXIT_LENGTH] += get_effective_balance(state, index) + state.latest_penalized_balances[current_epoch(state) % LATEST_PENALIZED_EXIT_LENGTH] += get_effective_balance(state, index) whistleblower_index = get_beacon_proposer_index(state, state.slot) whistleblower_reward = get_effective_balance(state, index) // WHISTLEBLOWER_REWARD_QUOTIENT state.validator_balances[whistleblower_index] += whistleblower_reward state.validator_balances[index] -= whistleblower_reward - validator.penalized_epoch = slot_to_epoch(state.slot) + validator.penalized_epoch = current_epoch(state) ``` ```python @@ -1594,16 +1602,15 @@ The steps below happen when `(state.slot + 1) % EPOCH_LENGTH == 0`. ### Helpers -* Let `current_epoch = slot_to_epoch(state.slot)`. -* Let `current_epoch_start_slot = current_epoch * EPOCH_LENGTH`. -* Let `next_epoch = slot_to_epoch(state.slot + 1)`. +* Let `current_epoch_start_slot = current_epoch(state) * EPOCH_LENGTH`. +* Let `next_epoch = current_epoch(state) + 1`. * Let `next_epoch_start_slot = next_epoch * EPOCH_LENGTH`. -* Let `previous_epoch = current_epoch - 1 if current_epoch > slot_to_epoch(GENESIS_SLOT) else current_epoch`. +* Let `previous_epoch = current_epoch(state) - 1 if current_epoch(state) > slot_to_epoch(GENESIS_SLOT) else current_epoch(state)`. * Let `previous_epoch_start_slot = previous_epoch * EPOCH_LENGTH`. All [validators](#dfn-validator): -* Let `active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch)`. +* Let `active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch(state))`. * Let `total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices])`. [Validators](#dfn-Validator) attesting during the current epoch: @@ -1650,7 +1657,7 @@ Define the following helpers to process attestation inclusion rewards and inclus ### Eth1 data -If `slot_to_epoch(state.slot) % ETH1_DATA_VOTING_PERIOD == 0`: +If `current_epoch(state) % ETH1_DATA_VOTING_PERIOD == 0`: * Set `state.latest_eth1_data = eth1_data_vote.data` if `eth1_data_vote.vote_count * 2 > ETH1_DATA_VOTING_PERIOD * EPOCH_LENGTH` for some `eth1_data_vote` in `state.eth1_data_votes`. * Set `state.eth1_data_votes = []`. @@ -1715,7 +1722,7 @@ Case 2: `epochs_since_finality > 4`: * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_justified_attester_indices`, loses `inactivity_penalty(state, index, epochs_since_finality)`. * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_boundary_attester_indices`, loses `inactivity_penalty(state, index, epochs_since_finality)`. * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_head_attester_indices`, loses `base_reward(state, index)`. -* Any [active_validator](#dfn-active-validator) `index` with `validator.penalized_epoch <= current_epoch`, loses `2 * inactivity_penalty(state, index, epochs_since_finality) + base_reward(state, index)`. +* Any [active_validator](#dfn-active-validator) `index` with `validator.penalized_epoch <= current_epoch(state)`, loses `2 * inactivity_penalty(state, index, epochs_since_finality) + base_reward(state, index)`. * Any [validator](#dfn-validator) `index` in `previous_epoch_attester_indices` loses `base_reward(state, index) - base_reward(state, index) * MIN_ATTESTATION_INCLUSION_DELAY // inclusion_distance(state, index)` #### Attestation inclusion @@ -1739,7 +1746,7 @@ def process_ejections(state: BeaconState) -> None: Iterate through the validator registry and eject active validators with balance below ``EJECTION_BALANCE``. """ - for index in get_active_validator_indices(state.validator_registry, current_epoch): + for index in get_active_validator_indices(state.validator_registry, current_epoch(state)): if state.validator_balances[index] < EJECTION_BALANCE: exit_validator(state, index) ``` @@ -1767,7 +1774,7 @@ def update_validator_registry(state: BeaconState) -> None: Note that this function mutates ``state``. """ # The active validators - active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch) + active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch(state)) # The total effective balance of active validators total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices]) @@ -1801,7 +1808,7 @@ def update_validator_registry(state: BeaconState) -> None: # Exit validator exit_validator(state, index) - state.validator_registry_update_epoch = slot_to_epoch(state.slot) + state.validator_registry_update_epoch = current_epoch(state) ``` and perform the following updates: @@ -1812,7 +1819,7 @@ and perform the following updates: If a validator registry update does _not_ happen do the following: -* Let `epochs_since_last_registry_change = current_epoch - state.validator_registry_update_epoch`. +* Let `epochs_since_last_registry_change = current_epoch(state) - state.validator_registry_update_epoch`. * If `epochs_since_last_registry_change` is an exact power of 2: * Set `state.current_calculation_epoch = next_epoch`. * Set `state.current_epoch_seed = generate_seed(state, state.current_calculation_epoch)` @@ -1830,8 +1837,8 @@ def process_penalties_and_exits(state: BeaconState) -> None: total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices]) for index, validator in enumerate(state.validator_registry): - if slot_to_epoch(state.slot) == validator.penalized_epoch + LATEST_PENALIZED_EXIT_LENGTH // 2: - e = slot_to_epoch(state.slot) % LATEST_PENALIZED_EXIT_LENGTH + if current_epoch(state) == validator.penalized_epoch + LATEST_PENALIZED_EXIT_LENGTH // 2: + e = current_epoch(state) % LATEST_PENALIZED_EXIT_LENGTH total_at_start = state.latest_penalized_balances[(e + 1) % LATEST_PENALIZED_EXIT_LENGTH] total_at_end = state.latest_penalized_balances[e] total_penalties = total_at_end - total_at_start @@ -1840,11 +1847,11 @@ def process_penalties_and_exits(state: BeaconState) -> None: def eligible(index): validator = state.validator_registry[index] - if validator.penalized_epoch <= slot_to_epoch(state.slot): + if validator.penalized_epoch <= current_epoch(state): PENALIZED_WITHDRAWAL_EPOCHS = LATEST_PENALIZED_EXIT_LENGTH // 2 - return slot_to_epoch(state.slot) >= validator.penalized_epoch + PENALIZED_WITHDRAWAL_EPOCHS + return current_epoch(state) >= validator.penalized_epoch + PENALIZED_WITHDRAWAL_EPOCHS else: - return slot_to_epoch(state.slot) >= validator.exit_epoch + MIN_VALIDATOR_WITHDRAWAL_EPOCHS + return current_epoch(state) >= validator.exit_epoch + MIN_VALIDATOR_WITHDRAWAL_EPOCHS all_indices = list(range(len(state.validator_registry))) eligible_indices = filter(eligible, all_indices) @@ -1859,7 +1866,7 @@ def process_penalties_and_exits(state: BeaconState) -> None: ### Final updates -* Set `state.latest_penalized_balances[(next_epoch) % LATEST_PENALIZED_EXIT_LENGTH] = state.latest_penalized_balances[current_epoch % LATEST_PENALIZED_EXIT_LENGTH]`. +* Set `state.latest_penalized_balances[(next_epoch) % LATEST_PENALIZED_EXIT_LENGTH] = state.latest_penalized_balances[current_epoch(state) % LATEST_PENALIZED_EXIT_LENGTH]`. * Remove any `attestation` in `state.latest_attestations` such that `attestation.data.slot < current_epoch_start_slot`. ## State root processing From c9494dbf8813f65b0d138f9b173aea2959f4a051 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sat, 26 Jan 2019 07:55:32 -0700 Subject: [PATCH 32/70] change crosslink.slot to crosslink.epoch --- specs/core/0_beacon-chain.md | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 49b4d0077..76f69f274 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -539,8 +539,8 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be ```python { - # Slot number - 'slot': 'uint64', + # Epoch number + 'epoch': 'uint64', # Shard block root 'shard_block_root': 'bytes32', } @@ -1291,7 +1291,7 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], finalized_slot=GENESIS_SLOT, # Recent state - latest_crosslinks=[Crosslink(slot=GENESIS_SLOT, shard_block_root=ZERO_HASH) for _ in range(SHARD_COUNT)], + latest_crosslinks=[Crosslink(epoch=slot_to_epoch(GENESIS_SLOT), shard_block_root=ZERO_HASH) for _ in range(SHARD_COUNT)], latest_block_roots=[ZERO_HASH for _ in range(LATEST_BLOCK_ROOTS_LENGTH)], latest_index_roots=[ZERO_HASH for _ in range(LATEST_INDEX_ROOTS_LENGTH)], latest_penalized_balances=[0 for _ in range(LATEST_PENALIZED_EXIT_LENGTH)], @@ -1318,7 +1318,7 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], if get_effective_balance(state, validator_index) >= MAX_DEPOSIT_AMOUNT: activate_validator(state, validator_index, True) - genesis_epoch = slot_to_epoch(GENESIS_SLOT) + genesis_epoch = current_epoch(state) state.latest_index_roots[genesis_epoch % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, genesis_epoch)) state.current_epoch_seed = generate_seed(state, genesis_epoch) @@ -1687,7 +1687,7 @@ Finally, update the following: For every `slot in range(previous_epoch_start_slot, next_epoch_start_slot)`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: -* Set `state.latest_crosslinks[shard] = Crosslink(slot=current_epoch_start_slot, shard_block_root=winning_root(crosslink_committee))` if `3 * total_attesting_balance(crosslink_committee) >= 2 * total_balance(crosslink_committee)`. +* Set `state.latest_crosslinks[shard] = Crosslink(epoch=current_epoch(state), shard_block_root=winning_root(crosslink_committee))` if `3 * total_attesting_balance(crosslink_committee) >= 2 * total_balance(crosslink_committee)`. ### Rewards and penalties @@ -1763,7 +1763,7 @@ First, update the following: If the following are satisfied: * `slot_to_epoch(state.finalized_slot) > state.validator_registry_update_epoch` -* `slot_to_epoch(state.latest_crosslinks[shard].slot) > state.validator_registry_update_epoch` for every shard number `shard` in `[(state.current_epoch_start_shard + i) % SHARD_COUNT for i in range(get_current_epoch_committee_count_per_slot(state) * EPOCH_LENGTH)]` (that is, for every shard in the current committees) +* `state.latest_crosslinks[shard].epoch > state.validator_registry_update_epoch` for every shard number `shard` in `[(state.current_epoch_start_shard + i) % SHARD_COUNT for i in range(get_current_epoch_committee_count_per_slot(state) * EPOCH_LENGTH)]` (that is, for every shard in the current committees) update the validator registry and associated fields by running From ae5dfab217e48e20c6f50543f017e0aa0ede11f1 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sat, 26 Jan 2019 08:16:32 -0700 Subject: [PATCH 33/70] convert finality vars to epochs and do some more epohh cleaning --- specs/core/0_beacon-chain.md | 108 +++++++++++++++++------------------ 1 file changed, 54 insertions(+), 54 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 76f69f274..57158fdd4 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -333,8 +333,8 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'shard_block_root': 'bytes32', # Last crosslink's hash of root 'latest_crosslink_root': 'bytes32', - # Slot of the last justified beacon block - 'justified_slot': 'uint64', + # Last justified epoch in the beacon state + 'justified_epoch': 'uint64', # Hash of the last justified beacon block 'justified_block_root': 'bytes32', } @@ -487,10 +487,10 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'custody_challenges': [CustodyChallenge], # Finality - 'previous_justified_slot': 'uint64', - 'justified_slot': 'uint64', + 'previous_justified_epoch': 'uint64', + 'justified_epoch': 'uint64', 'justification_bitfield': 'uint64', - 'finalized_slot': 'uint64', + 'finalized_epoch': 'uint64', # Recent state 'latest_crosslinks': [Crosslink], @@ -726,7 +726,7 @@ The beacon chain fork choice rule is a hybrid that combines justification and fi def lmd_ghost(store, start): validators = start.state.validator_registry active_validators = [validators[i] for i in - get_active_validator_indices(validators, start.state.slot)] + get_active_validator_indices(validators, current_epoch(start.state))] attestation_targets = [get_latest_attestation_target(store, validator) for validator in active_validators] def get_vote_count(block): @@ -781,21 +781,21 @@ def current_epoch(state: BeaconState) -> int: #### `is_active_validator` ```python -def is_active_validator(validator: Validator, slot: int) -> bool: +def is_active_validator(validator: Validator, epoch: int) -> bool: """ Checks if ``validator`` is active. """ - return validator.activation_epoch <= slot_to_epoch(slot) < validator.exit_epoch + return validator.activation_epoch <= epoch < validator.exit_epoch ``` #### `get_active_validator_indices` ```python -def get_active_validator_indices(validators: [Validator], slot: int) -> List[int]: +def get_active_validator_indices(validators: [Validator], epoch: int) -> List[int]: """ Gets indices of active validators from ``validators``. """ - return [i for i, v in enumerate(validators) if is_active_validator(v, slot)] + return [i for i, v in enumerate(validators) if is_active_validator(v, epoch)] ``` #### `shuffle` @@ -890,7 +890,7 @@ def get_shuffling(seed: Bytes32, committee is itself a list of validator indices. """ - active_validator_indices = get_active_validator_indices(validators, slot) + active_validator_indices = get_active_validator_indices(validators, epoch) committees_per_slot = get_committee_count_per_slot(len(active_validator_indices)) @@ -936,11 +936,11 @@ def get_crosslink_committees_at_slot(state: BeaconState, """ Returns the list of ``(committee, shard)`` tuples for the ``slot``. """ - state_epoch_slot = state.slot - (state.slot % EPOCH_LENGTH) - assert state_epoch_slot <= slot + EPOCH_LENGTH - assert slot < state_epoch_slot + EPOCH_LENGTH + current_epoch_slot = current_epoch(state) * EPOCH_LENGTH + assert current_epoch_slot <= slot + EPOCH_LENGTH + assert slot < current_epoch_slot + EPOCH_LENGTH - if slot < state_epoch_slot: + if slot < current_epoch_slot: committees_per_slot = get_previous_epoch_committee_count_per_slot(state) seed = state.previous_epoch_seed shuffling_epoch = state.previous_calculation_epoch @@ -1171,8 +1171,8 @@ def is_surround_vote(attestation_data_1: AttestationData, Note: parameter order matters as this function only checks that ``attestation_data_1`` surrounds ``attestation_data_2``. """ - source_epoch_1 = slot_to_epoch(attestation_data_1.justified_slot) - source_epoch_2 = slot_to_epoch(attestation_data_2.justified_slot) + source_epoch_1 = attestation_data_1.justified_epoch + source_epoch_2 = attestation_data_2.justified_epoch target_epoch_1 = slot_to_epoch(attestation_data_1.slot) target_epoch_2 = slot_to_epoch(attestation_data_2.slot) return ( @@ -1201,12 +1201,12 @@ def integer_squareroot(n: int) -> int: #### `entry_exit_effect_epoch` ```python -def entry_exit_effect_epoch(slot: int) -> int: +def entry_exit_effect_epoch(epoch: int) -> int: """ - An entry or exit triggered in the slot given by the input takes effect at + An entry or exit triggered in the ``epoch`` given by the input takes effect at the epoch given by the output. """ - return slot_to_epoch(slot) + 1 + ENTRY_EXIT_DELAY + return epoch + 1 + ENTRY_EXIT_DELAY ``` #### `bls_verify` @@ -1255,6 +1255,7 @@ A valid block with slot `GENESIS_SLOT` (a "genesis block") has the following val def get_initial_beacon_state(initial_validator_deposits: List[Deposit], genesis_time: int, latest_eth1_data: Eth1Data) -> BeaconState: + genesis_epoch = slot_to_epoch(GENESIS_SLOT) state = BeaconState( # Misc slot=GENESIS_SLOT, @@ -1268,7 +1269,7 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], # Validator registry validator_registry=[], validator_balances=[], - validator_registry_update_epoch=slot_to_epoch(GENESIS_SLOT), + validator_registry_update_epoch=genesis_epoch, validator_registry_exit_count=0, # Randomness and committees @@ -1276,8 +1277,8 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], latest_vdf_outputs=[ZERO_HASH for _ in range(LATEST_RANDAO_MIXES_LENGTH // EPOCH_LENGTH)], previous_epoch_start_shard=GENESIS_START_SHARD, current_epoch_start_shard=GENESIS_START_SHARD, - previous_calculation_epoch=slot_to_epoch(GENESIS_SLOT), - current_calculation_epoch=slot_to_epoch(GENESIS_SLOT), + previous_calculation_epoch=genesis_epoch, + current_calculation_epoch=genesis_epoch, previous_epoch_seed=ZERO_HASH, current_epoch_seed=ZERO_HASH, @@ -1285,13 +1286,13 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], custody_challenges=[], # Finality - previous_justified_slot=GENESIS_SLOT, - justified_slot=GENESIS_SLOT, + previous_justified_epoch=genesis_epoch, + justified_epoch=genesis_epoch, justification_bitfield=0, - finalized_slot=GENESIS_SLOT, + finalized_epoch=genesis_epoch, # Recent state - latest_crosslinks=[Crosslink(epoch=slot_to_epoch(GENESIS_SLOT), shard_block_root=ZERO_HASH) for _ in range(SHARD_COUNT)], + latest_crosslinks=[Crosslink(epoch=genesis_epoch, shard_block_root=ZERO_HASH) for _ in range(SHARD_COUNT)], latest_block_roots=[ZERO_HASH for _ in range(LATEST_BLOCK_ROOTS_LENGTH)], latest_index_roots=[ZERO_HASH for _ in range(LATEST_INDEX_ROOTS_LENGTH)], latest_penalized_balances=[0 for _ in range(LATEST_PENALIZED_EXIT_LENGTH)], @@ -1318,7 +1319,6 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], if get_effective_balance(state, validator_index) >= MAX_DEPOSIT_AMOUNT: activate_validator(state, validator_index, True) - genesis_epoch = current_epoch(state) state.latest_index_roots[genesis_epoch % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, genesis_epoch)) state.current_epoch_seed = generate_seed(state, genesis_epoch) @@ -1409,7 +1409,7 @@ Note: All functions in this section mutate `state`. def activate_validator(state: BeaconState, index: int, genesis: bool) -> None: validator = state.validator_registry[index] - validator.activation_epoch = slot_to_epoch(GENESIS_SLOT) if genesis else entry_exit_effect_epoch(state.slot) + validator.activation_epoch = slot_to_epoch(GENESIS_SLOT) if genesis else entry_exit_effect_epoch(current_epoch(state)) ``` ```python @@ -1423,10 +1423,10 @@ def exit_validator(state: BeaconState, index: int) -> None: validator = state.validator_registry[index] # The following updates only occur if not previous exited - if validator.exit_epoch <= entry_exit_effect_epoch(state.slot): + if validator.exit_epoch <= entry_exit_effect_epoch(current_epoch(state)): return - validator.exit_epoch = entry_exit_effect_epoch(state.slot) + validator.exit_epoch = entry_exit_effect_epoch(current_epoch(state)) state.validator_registry_exit_count += 1 validator.exit_count = state.validator_registry_exit_count @@ -1504,7 +1504,7 @@ For each `proposer_slashing` in `block.body.proposer_slashings`: * Verify that `proposer_slashing.proposal_data_1.slot == proposer_slashing.proposal_data_2.slot`. * Verify that `proposer_slashing.proposal_data_1.shard == proposer_slashing.proposal_data_2.shard`. * Verify that `proposer_slashing.proposal_data_1.block_root != proposer_slashing.proposal_data_2.block_root`. -* Verify that `proposer.penalized_slot > state.slot`. +* Verify that `proposer.penalized_epoch > current_epoch(state)`. * Verify that `bls_verify(pubkey=proposer.pubkey, message=hash_tree_root(proposer_slashing.proposal_data_1), signature=proposer_slashing.proposal_signature_1, domain=get_domain(state.fork, proposer_slashing.proposal_data_1.slot, DOMAIN_PROPOSAL))`. * Verify that `bls_verify(pubkey=proposer.pubkey, message=hash_tree_root(proposer_slashing.proposal_data_2), signature=proposer_slashing.proposal_signature_2, domain=get_domain(state.fork, proposer_slashing.proposal_data_2.slot, DOMAIN_PROPOSAL))`. * Run `penalize_validator(state, proposer_slashing.proposer_index)`. @@ -1524,7 +1524,7 @@ For each `casper_slashing` in `block.body.casper_slashings`: * Verify that `is_double_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)` or `is_surround_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)`. * Verify that `verify_slashable_vote_data(state, slashable_vote_data_1)`. * Verify that `verify_slashable_vote_data(state, slashable_vote_data_2)`. -* For each [validator](#dfn-validator) index `i` in `intersection` run `penalize_validator(state, i)` if `state.validator_registry[i].penalized_slot > state.slot`. +* For each [validator](#dfn-validator) index `i` in `intersection` run `penalize_validator(state, i)` if `state.validator_registry[i].penalized_epoch > current_epoch(state)`. #### Attestations @@ -1534,8 +1534,8 @@ For each `attestation` in `block.body.attestations`: * Verify that `attestation.data.slot + MIN_ATTESTATION_INCLUSION_DELAY <= state.slot`. * Verify that `attestation.data.slot + EPOCH_LENGTH >= state.slot`. -* Verify that `attestation.data.justified_slot` is equal to `state.justified_slot if attestation.data.slot >= state.slot - (state.slot % EPOCH_LENGTH) else state.previous_justified_slot`. -* Verify that `attestation.data.justified_block_root` is equal to `get_block_root(state, attestation.data.justified_slot)`. +* Verify that `attestation.data.justified_epoch` is equal to `state.justified_epoch if attestation.data.slot >= state.slot - (state.slot % EPOCH_LENGTH) else state.previous_justified_epoch`. +* Verify that `attestation.data.justified_block_root` is equal to `get_block_root(state, attestation.data.justified_epoch * EPOCH_LENGTH)`. * Verify that either `attestation.data.latest_crosslink_root` or `attestation.data.shard_block_root` equals `state.latest_crosslinks[shard].shard_block_root`. * `aggregate_signature` verification: * Let `participants = get_attestation_participants(state, attestation.data, attestation.aggregation_bitfield)`. @@ -1586,7 +1586,7 @@ Verify that `len(block.body.exits) <= MAX_EXITS`. For each `exit` in `block.body.exits`: * Let `validator = state.validator_registry[exit.validator_index]`. -* Verify that `validator.exit_epoch > entry_exit_effect_epoch(state.slot)`. +* Verify that `validator.exit_epoch > entry_exit_effect_epoch(current_epoch(state))`. * Verify that `state.slot >= exit.slot`. * Let `exit_message = hash_tree_root(Exit(slot=exit.slot, validator_index=exit.validator_index, signature=EMPTY_SIGNATURE))`. * Verify that `bls_verify(pubkey=validator.pubkey, message=exit_message, signature=exit.signature, domain=get_domain(state.fork, exit.slot, DOMAIN_EXIT))`. @@ -1617,7 +1617,7 @@ All [validators](#dfn-validator): * Let `current_epoch_attestations = [a for a in state.latest_attestations if current_epoch_start_slot <= a.data.slot < next_epoch_start_slot]`. (Note: this is the set of attestations of slots in the epoch `current_epoch_start_slot...next_epoch_start_slot`, _not_ attestations that got included in the chain during the epoch `current_epoch_start_slot...next_epoch_start_slot`.) * Validators justifying the epoch boundary block at the start of the current epoch: - * Let `current_epoch_boundary_attestations = [a for a in current_epoch_attestations if a.data.epoch_boundary_root == get_block_root(state, current_epoch_start_slot) and a.data.justified_slot == state.justified_slot]`. + * Let `current_epoch_boundary_attestations = [a for a in current_epoch_attestations if a.data.epoch_boundary_root == get_block_root(state, current_epoch_start_slot) and a.data.justified_epoch == state.justified_epoch]`. * Let `current_epoch_boundary_attester_indices` be the union of the [validator](#dfn-validator) index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in current_epoch_boundary_attestations]`. * Let `current_epoch_boundary_attesting_balance = sum([get_effective_balance(state, i) for i in current_epoch_boundary_attester_indices])`. @@ -1627,7 +1627,7 @@ All [validators](#dfn-validator): * Let `previous_epoch_attestations = [a for a in state.latest_attestations if previous_epoch_start_slot <= a.data.slot < current_epoch_start_slot]`. * Let `previous_epoch_attester_indices` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in previous_epoch_attestations]`. * Validators targeting the previous justified slot: - * Let `previous_epoch_justified_attestations = [a for a in current_epoch_attestations + previous_epoch_attestations if a.data.justified_slot == state.previous_justified_slot]`. + * Let `previous_epoch_justified_attestations = [a for a in current_epoch_attestations + previous_epoch_attestations if a.data.justified_epoch == state.previous_justified_epoch]`. * Let `previous_epoch_justified_attester_indices` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in previous_epoch_justified_attestations]`. * Let `previous_epoch_justified_attesting_balance = sum([get_effective_balance(state, i) for i in previous_epoch_justified_attester_indices])`. * Validators justifying the epoch boundary block at the start of the previous epoch: @@ -1666,22 +1666,22 @@ If `current_epoch(state) % ETH1_DATA_VOTING_PERIOD == 0`: First, update the justification bitfield: -* Let `new_justified_slot = state.justified_slot`. +* Let `new_justified_epoch = state.justified_epoch`. * Set `state.justification_bitfield = (state.justification_bitfield * 2) % 2**64`. -* Set `state.justification_bitfield |= 2` and `new_justified_slot = previous_epoch_start_slot` if `3 * previous_epoch_boundary_attesting_balance >= 2 * total_balance`. -* Set `state.justification_bitfield |= 1` and `new_justified_slot = current_epoch_start_slot` if `3 * current_epoch_boundary_attesting_balance >= 2 * total_balance`. +* Set `state.justification_bitfield |= 2` and `new_justified_epoch = previous_epoch` if `3 * previous_epoch_boundary_attesting_balance >= 2 * total_balance`. +* Set `state.justification_bitfield |= 1` and `new_justified_epoch = current_epoch(state)` if `3 * current_epoch_boundary_attesting_balance >= 2 * total_balance`. Next, update last finalized slot if possible: -* Set `state.finalized_slot = state.previous_justified_slot` if `(state.justification_bitfield >> 1) % 8 == 0b111 and state.previous_justified_slot == previous_epoch_start_slot - 2 * EPOCH_LENGTH`. -* Set `state.finalized_slot = state.previous_justified_slot` if `(state.justification_bitfield >> 1) % 4 == 0b11 and state.previous_justified_slot == previous_epoch_start_slot - EPOCH_LENGTH`. -* Set `state.finalized_slot = state.justified_slot` if `(state.justification_bitfield >> 0) % 8 == 0b111 and state.justified_slot == previous_epoch_start_slot - EPOCH_LENGTH`. -* Set `state.finalized_slot = state.justified_slot` if `(state.justification_bitfield >> 0) % 4 == 0b11 and state.justified_slot == previous_epoch_start_slot`. +* Set `state.finalized_epoch = state.previous_justified_epoch` if `(state.justification_bitfield >> 1) % 8 == 0b111 and state.previous_justified_epoch == previous_epoch - 2`. +* Set `state.finalized_epoch = state.previous_justified_epoch` if `(state.justification_bitfield >> 1) % 4 == 0b11 and state.previous_justified_epoch == previous_epoch - 1`. +* Set `state.finalized_epoch = state.justified_epoch` if `(state.justification_bitfield >> 0) % 8 == 0b111 and state.justified_epoch == previous_epoch - 1`. +* Set `state.finalized_epoch = state.justified_epoch` if `(state.justification_bitfield >> 0) % 4 == 0b11 and state.justified_epoch == previous_epoch`. Finally, update the following: -* Set `state.previous_justified_slot = state.justified_slot`. -* Set `state.justified_slot = justified_slot`. +* Set `state.previous_justified_epoch = state.justified_epoch`. +* Set `state.justified_epoch = new_justified_epoch`. ### Crosslinks @@ -1701,7 +1701,7 @@ First, we define some additional helpers: Note: When applying penalties in the following balance recalculations implementers should make sure the `uint64` does not underflow. -* Let `epochs_since_finality = next_epoch - slot_to_epoch(state.finalized_slot)`. +* Let `epochs_since_finality = next_epoch - state.finalized_epoch`. Case 1: `epochs_since_finality <= 4`: @@ -1758,11 +1758,11 @@ First, update the following: * Set `state.previous_calculation_epoch = state.current_calculation_epoch`. * Set `state.previous_epoch_start_shard = state.current_epoch_start_shard`. * Set `state.previous_epoch_seed = state.current_epoch_seed`. -* Set `state.latest_index_roots[next_epoch % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, next_epoch_start_slot))`. +* Set `state.latest_index_roots[next_epoch % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, next_epoch))`. If the following are satisfied: -* `slot_to_epoch(state.finalized_slot) > state.validator_registry_update_epoch` +* `state.finalized_epoch > state.validator_registry_update_epoch` * `state.latest_crosslinks[shard].epoch > state.validator_registry_update_epoch` for every shard number `shard` in `[(state.current_epoch_start_shard + i) % SHARD_COUNT for i in range(get_current_epoch_committee_count_per_slot(state) * EPOCH_LENGTH)]` (that is, for every shard in the current committees) update the validator registry and associated fields by running @@ -1787,7 +1787,7 @@ def update_validator_registry(state: BeaconState) -> None: # Activate validators within the allowable balance churn balance_churn = 0 for index, validator in enumerate(state.validator_registry): - if validator.activation_epoch > entry_exit_effect_epoch(state.slot) and state.validator_balances[index] >= MAX_DEPOSIT_AMOUNT: + if validator.activation_epoch > entry_exit_effect_epoch(current_epoch(state)) and state.validator_balances[index] >= MAX_DEPOSIT_AMOUNT: # Check the balance churn would be within the allowance balance_churn += get_effective_balance(state, index) if balance_churn > max_balance_churn: @@ -1799,7 +1799,7 @@ def update_validator_registry(state: BeaconState) -> None: # Exit validators within the allowable balance churn balance_churn = 0 for index, validator in enumerate(state.validator_registry): - if validator.exit_epoch > entry_exit_effect_epoch(state.slot) and validator.status_flags & INITIATED_EXIT: + if validator.exit_epoch > entry_exit_effect_epoch(current_epoch(state)) and validator.status_flags & INITIATED_EXIT: # Check the balance churn would be within the allowance balance_churn += get_effective_balance(state, index) if balance_churn > max_balance_churn: @@ -1832,7 +1832,7 @@ Regardless of whether or not a validator set change happens, run the following: ```python def process_penalties_and_exits(state: BeaconState) -> None: # The active validators - active_validator_indices = get_active_validator_indices(state.validator_registry, state.slot) + active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch(state)) # The total effective balance of active validators total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices]) @@ -1867,7 +1867,7 @@ def process_penalties_and_exits(state: BeaconState) -> None: ### Final updates * Set `state.latest_penalized_balances[(next_epoch) % LATEST_PENALIZED_EXIT_LENGTH] = state.latest_penalized_balances[current_epoch(state) % LATEST_PENALIZED_EXIT_LENGTH]`. -* Remove any `attestation` in `state.latest_attestations` such that `attestation.data.slot < current_epoch_start_slot`. +* Remove any `attestation` in `state.latest_attestations` such that `slot_to_epoch(attestation.data.slot) < current_epoch(state)`. ## State root processing From 6e16cdc00e6e5492e5046b562db82666293d31b3 Mon Sep 17 00:00:00 2001 From: Justin Date: Sat, 26 Jan 2019 18:59:07 +0000 Subject: [PATCH 34/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 5c0663242..4da97cc54 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -167,7 +167,7 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `EJECTION_BALANCE` | `2**4 * 1e9` (= 16,000,000,000) | Gwei | | `MAX_BALANCE_CHURN_QUOTIENT` | `2**5` (= 32) | - | | `BEACON_CHAIN_SHARD_NUMBER` | `2**64 - 1` | - | -| `MAX_CASPER_VOTES` | `2**10` (= 1,024) | votes | +| `MAX_CASPER_VOTES` | `2**12` (= 4,096) | votes | | `LATEST_BLOCK_ROOTS_LENGTH` | `2**13` (= 8,192) | block roots | | `LATEST_RANDAO_MIXES_LENGTH` | `2**13` (= 8,192) | randao mixes | | `LATEST_PENALIZED_EXIT_LENGTH` | `2**13` (= 8,192) | epochs | ~36 days | @@ -232,7 +232,7 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | Name | Value | | - | - | | `MAX_PROPOSER_SLASHINGS` | `2**4` (= 16) | -| `MAX_CASPER_SLASHINGS` | `2**4` (= 16) | +| `MAX_CASPER_SLASHINGS` | `2**0` (= 1) | | `MAX_ATTESTATIONS` | `2**7` (= 128) | | `MAX_DEPOSITS` | `2**4` (= 16) | | `MAX_EXITS` | `2**4` (= 16) | @@ -1029,6 +1029,8 @@ def get_attestation_participants(state: BeaconState, assert attestation_data.shard in [shard for _, shard in crosslink_committees] crosslink_committee = [committee for committee, shard in crosslink_committees if shard == attestation_data.shard][0] + assert verify_bitfield(bitfield, len(crosslink_committee)) + # Find the participating attesters in the committee participants = [] for i, validator_index in enumerate(crosslink_committee): @@ -1088,14 +1090,14 @@ def get_bitfield_bit(bitfield: bytes, i: int) -> int: #### `verify_bitfield` ```python -def verify_bitfield(bitfield: bytes, size: int) -> bool: +def verify_bitfield(bitfield: bytes, committee_size: int) -> bool: """ - Verify ``bitfield`` against the ``size``. + Verify ``bitfield`` against the ``committee_size``. """ - if len(bitfield) != (size + 7) // 8: + if len(bitfield) != (committee_size + 7) // 8: return False - for i in range(size + 1, size - size % 8 + 8): + for i in range(committee_size + 1, committee_size - committee_size % 8 + 8): if get_bitfield_bit(bitfield, i) != 0: return False @@ -1109,7 +1111,7 @@ def verify_slashable_vote_data(state: BeaconState, slashable_vote_data: Slashabl """ Verify validity of ``slashable_vote_data`` fields. """ - if slashable_vote_data.custody_bitfield != 0: # [TO BE REMOVED IN PHASE 1] + if slashable_vote_data.custody_bitfield != b'\x00' * len(slashable_vote_data.custody_bitfield): # [TO BE REMOVED IN PHASE 1] return False if len(slashable_vote_data.validator_indices) == 0: @@ -1536,9 +1538,10 @@ For each `attestation` in `block.body.attestations`: * Verify bitfields: ```python - assert verify_bitfield(attestation.aggregation_bitfield) - assert verify_bitfield(attestation.custody_bitfield) - assert attestation.custody_bitfield & attestation.aggregation_bitfield == attestation.custody_bitfield + for i in range(len(crosslink_committee)): + if get_bitfield_bit(attestation.aggregation_bitfield) == 0: + assert get_bitfield_bit(attestation.custody_bitfield) == 0 + assert attestation.custody_bitfield == 0 # [TO BE REMOVED IN PHASE 1] ``` From c3aff31da862e0a585405597f8da85ade2a04ca2 Mon Sep 17 00:00:00 2001 From: Justin Date: Sat, 26 Jan 2019 19:06:46 +0000 Subject: [PATCH 35/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 898f9ae3d..906d3e1b5 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1551,19 +1551,15 @@ For each `attestation` in `block.body.attestations`: * Verify that `attestation.data.justified_slot` is equal to `state.justified_slot if attestation.data.slot >= state.slot - (state.slot % EPOCH_LENGTH) else state.previous_justified_slot`. * Verify that `attestation.data.justified_block_root` is equal to `get_block_root(state, attestation.data.justified_slot)`. * Verify that either `attestation.data.latest_crosslink_root` or `attestation.data.shard_block_root` equals `state.latest_crosslinks[shard].shard_block_root`. -* Verify bitfields: +* Verify bitfields and aggregate signature: ```python + assert attestation.custody_bitfield == 0 # [TO BE REMOVED IN PHASE 1] + for i in range(len(crosslink_committee)): if get_bitfield_bit(attestation.aggregation_bitfield) == 0: assert get_bitfield_bit(attestation.custody_bitfield) == 0 - assert attestation.custody_bitfield == 0 # [TO BE REMOVED IN PHASE 1] -``` - -* Verify aggregate signature: - -```python participants = get_attestation_participants(state, attestation.data, attestation.aggregation_bitfield) custody_bit_0_participants = get_attestation_participants(state, attestation.data, attestation.custody_bitfield) custody_bit_1_participants = [i in participants for i not in custody_bit_0_participants] From a81092627a4bfedc0427cd5b9ffa1e491d16f321 Mon Sep 17 00:00:00 2001 From: Justin Date: Sat, 26 Jan 2019 19:10:21 +0000 Subject: [PATCH 36/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 906d3e1b5..0648a351c 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -167,7 +167,7 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `EJECTION_BALANCE` | `2**4 * 1e9` (= 16,000,000,000) | Gwei | | `MAX_BALANCE_CHURN_QUOTIENT` | `2**5` (= 32) | - | | `BEACON_CHAIN_SHARD_NUMBER` | `2**64 - 1` | - | -| `MAX_CASPER_VOTES` | `2**12` (= 4,096) | votes | +| `MAX_INDICES_PER_SLASHABLE_VOTE` | `2**12` (= 4,096) | votes | | `LATEST_BLOCK_ROOTS_LENGTH` | `2**13` (= 8,192) | block roots | | `LATEST_RANDAO_MIXES_LENGTH` | `2**13` (= 8,192) | randao mixes | | `LATEST_INDEX_ROOTS_LENGTH` | `2**13` (= 8,192) | index roots | @@ -1147,7 +1147,7 @@ def verify_slashable_vote_data(state: BeaconState, slashable_vote_data: Slashabl if not verify_bitfield(slashable_vote_data.custody_bitfield, len(slashable_vote_data.validator_indices)): return False - if len(slashable_vote_data.validator_indices) > MAX_CASPER_VOTES: + if len(slashable_vote_data.validator_indices) > MAX_INDICES_PER_SLASHABLE_VOTE: return False custody_bit_0_indices = [] From 1a4107876823f4c6060f25ba79cff89c988a2a1c Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sat, 26 Jan 2019 12:13:12 -0700 Subject: [PATCH 37/70] randao reveal is signed epoch number (#498) --- specs/core/0_beacon-chain.md | 8 ++------ specs/validator/0_beacon-chain-validator.md | 6 +++--- 2 files changed, 5 insertions(+), 9 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index c7bef5c25..5a185f63f 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -514,8 +514,6 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git 'pubkey': 'bytes48', # Withdrawal credentials 'withdrawal_credentials': 'bytes32', - # Number of proposer slots since genesis - 'proposer_slots': 'uint64', # Slot when validator activated 'activation_slot': 'uint64', # Slot when validator exited @@ -1368,7 +1366,6 @@ def process_deposit(state: BeaconState, validator = Validator( pubkey=pubkey, withdrawal_credentials=withdrawal_credentials, - proposer_slots=0, activation_slot=FAR_FUTURE_SLOT, exit_slot=FAR_FUTURE_SLOT, withdrawal_slot=FAR_FUTURE_SLOT, @@ -1447,7 +1444,6 @@ Below are the processing steps that happen at every slot. ### Misc counters * Set `state.slot += 1`. -* Set `state.validator_registry[get_beacon_proposer_index(state, state.slot)].proposer_slots += 1`. * Set `state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH] = state.latest_randao_mixes[(state.slot - 1) % LATEST_RANDAO_MIXES_LENGTH]` ### Block roots @@ -1473,8 +1469,8 @@ Below are the processing steps that happen at every `block`. ### RANDAO * Let `proposer = state.validator_registry[get_beacon_proposer_index(state, state.slot)]`. -* Verify that `bls_verify(pubkey=proposer.pubkey, message=int_to_bytes32(proposer.proposer_slots), signature=block.randao_reveal, domain=get_domain(state.fork, state.slot, DOMAIN_RANDAO))`. -* Set `state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH] = hash(state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH] + block.randao_reveal)`. +* Verify that `bls_verify(pubkey=proposer.pubkey, message=int_to_bytes32(state.slot // EPOCH_LENGTH), signature=block.randao_reveal, domain=get_domain(state.fork, state.slot, DOMAIN_RANDAO))`. +* Set `state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH] = xor(state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH], hash(block.randao_reveal))`. ### Eth1 data diff --git a/specs/validator/0_beacon-chain-validator.md b/specs/validator/0_beacon-chain-validator.md index 29ec0c7e0..83ebb5751 100644 --- a/specs/validator/0_beacon-chain-validator.md +++ b/specs/validator/0_beacon-chain-validator.md @@ -158,12 +158,12 @@ _Note_: To calculate `state_root`, the validator should first run the state tran ##### Randao reveal -Set `block.randao_reveal = reveal_signature` where `reveal_signature` is defined as: +Set `block.randao_reveal = epoch_signature` where `epoch_signature` is defined as: ```python -reveal_signature = bls_sign( +epoch_signature = bls_sign( privkey=validator.privkey, # privkey store locally, not in state - message=int_to_bytes32(validator.proposer_slots + 1), + message=int_to_bytes32(block.slot // EPOCH_LENGTH), domain=get_domain( fork_data, # `fork_data` is the fork_data at the slot `block.slot` block.slot, From cfb1cb57b8bd7db23f8a7feaaf33b708036f4c11 Mon Sep 17 00:00:00 2001 From: Justin Date: Sat, 26 Jan 2019 19:25:18 +0000 Subject: [PATCH 38/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 54 ++++++++++++++++++------------------ 1 file changed, 27 insertions(+), 27 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 0648a351c..9d1fd14b7 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -25,7 +25,7 @@ - [`ProposerSlashing`](#proposerslashing) - [Casper slashings](#casper-slashings) - [`CasperSlashing`](#casperslashing) - - [`SlashableVoteData`](#slashablevotedata) + - [`SlashableVote`](#SlashableVote) - [Attestations](#attestations) - [`Attestation`](#attestation) - [`AttestationData`](#attestationdata) @@ -82,7 +82,7 @@ - [`get_domain`](#get_domain) - [`get_bitfield_bit`](#get_bitfield_bit) - [`verify_bitfield`](#verify_bitfield) - - [`verify_slashable_vote_data`](#verify_slashable_vote_data) + - [`verify_slashable_vote`](#verify_slashable_vote) - [`is_double_vote`](#is_double_vote) - [`is_surround_vote`](#is_surround_vote) - [`integer_squareroot`](#integer_squareroot) @@ -280,13 +280,13 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git ```python { # First batch of votes - 'slashable_vote_data_1': SlashableVoteData, + 'slashable_vote_1': SlashableVote, # Second batch of votes - 'slashable_vote_data_2': SlashableVoteData, + 'slashable_vote_2': SlashableVote, } ``` -##### `SlashableVoteData` +##### `SlashableVote` ```python { @@ -1127,33 +1127,33 @@ def verify_bitfield(bitfield: bytes, committee_size: int) -> bool: return True ``` -#### `verify_slashable_vote_data` +#### `verify_slashable_vote` ```python -def verify_slashable_vote_data(state: BeaconState, slashable_vote_data: SlashableVoteData) -> bool: +def verify_slashable_vote(state: BeaconState, slashable_vote: SlashableVote) -> bool: """ - Verify validity of ``slashable_vote_data`` fields. + Verify validity of ``slashable_vote`` fields. """ - if slashable_vote_data.custody_bitfield != b'\x00' * len(slashable_vote_data.custody_bitfield): # [TO BE REMOVED IN PHASE 1] + if slashable_vote.custody_bitfield != b'\x00' * len(slashable_vote.custody_bitfield): # [TO BE REMOVED IN PHASE 1] return False - if len(slashable_vote_data.validator_indices) == 0: + if len(slashable_vote.validator_indices) == 0: return False - for i in range(len(slashable_vote_data.validator_indices) - 1): - if slashable_vote_data.validator_indices[i] >= slashable_vote_data.validator_indices[i + 1]: + for i in range(len(slashable_vote.validator_indices) - 1): + if slashable_vote.validator_indices[i] >= slashable_vote.validator_indices[i + 1]: return False - if not verify_bitfield(slashable_vote_data.custody_bitfield, len(slashable_vote_data.validator_indices)): + if not verify_bitfield(slashable_vote.custody_bitfield, len(slashable_vote.validator_indices)): return False - if len(slashable_vote_data.validator_indices) > MAX_INDICES_PER_SLASHABLE_VOTE: + if len(slashable_vote.validator_indices) > MAX_INDICES_PER_SLASHABLE_VOTE: return False custody_bit_0_indices = [] custody_bit_1_indices = [] - for i, validator_index in enumerate(slashable_vote_data.validator_indices): - if get_bitfield_bit(slashable_vote_data.custody_bitfield, i) == 0: + for i, validator_index in enumerate(slashable_vote.validator_indices): + if get_bitfield_bit(slashable_vote.custody_bitfield, i) == 0: custody_bit_0_indices.append(validator_index) else: custody_bit_1_indices.append(validator_index) @@ -1164,11 +1164,11 @@ def verify_slashable_vote_data(state: BeaconState, slashable_vote_data: Slashabl bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in custody_bit_1_indices]), ], messages=[ - hash_tree_root(AttestationDataAndCustodyBit(slashable_vote_data.data, 0)), - hash_tree_root(AttestationDataAndCustodyBit(slashable_vote_data.data, 1)), + hash_tree_root(AttestationDataAndCustodyBit(slashable_vote.data, 0)), + hash_tree_root(AttestationDataAndCustodyBit(slashable_vote.data, 1)), ], - signature=slashable_vote_data.aggregate_signature, - domain=get_domain(state.fork, slashable_vote_data.data.slot, DOMAIN_ATTESTATION), + signature=slashable_vote.aggregate_signature, + domain=get_domain(state.fork, slashable_vote.data.slot, DOMAIN_ATTESTATION), ) ``` @@ -1530,14 +1530,14 @@ Verify that `len(block.body.casper_slashings) <= MAX_CASPER_SLASHINGS`. For each `casper_slashing` in `block.body.casper_slashings`: -* Let `slashable_vote_data_1 = casper_slashing.slashable_vote_data_1`. -* Let `slashable_vote_data_2 = casper_slashing.slashable_vote_data_2`. -* Let `intersection = [x for x in slashable_vote_data_1.validator_indices if x in slashable_vote_data_2.validator_indices]`. +* Let `slashable_vote_1 = casper_slashing.slashable_vote_1`. +* Let `slashable_vote_2 = casper_slashing.slashable_vote_2`. +* Let `intersection = [x for x in slashable_vote_1.validator_indices if x in slashable_vote_2.validator_indices]`. * Verify that `len(intersection) >= 1`. -* Verify that `slashable_vote_data_1.data != slashable_vote_data_2.data`. -* Verify that `is_double_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)` or `is_surround_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)`. -* Verify that `verify_slashable_vote_data(state, slashable_vote_data_1)`. -* Verify that `verify_slashable_vote_data(state, slashable_vote_data_2)`. +* Verify that `slashable_vote_1.data != slashable_vote_2.data`. +* Verify that `is_double_vote(slashable_vote_1.data, slashable_vote_2.data)` or `is_surround_vote(slashable_vote_1.data, slashable_vote_2.data)`. +* Verify that `verify_slashable_vote(state, slashable_vote_1)`. +* Verify that `verify_slashable_vote(state, slashable_vote_2)`. * For each [validator](#dfn-validator) index `i` in `intersection` run `penalize_validator(state, i)` if `state.validator_registry[i].penalized_slot > state.slot`. #### Attestations From aa909bddf3f32115ecfbd2bb5ddbeb0efab6f976 Mon Sep 17 00:00:00 2001 From: Justin Date: Sat, 26 Jan 2019 19:25:58 +0000 Subject: [PATCH 39/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 9d1fd14b7..9a3590d9a 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -25,7 +25,7 @@ - [`ProposerSlashing`](#proposerslashing) - [Casper slashings](#casper-slashings) - [`CasperSlashing`](#casperslashing) - - [`SlashableVote`](#SlashableVote) + - [`SlashableVote`](#slashablevote) - [Attestations](#attestations) - [`Attestation`](#attestation) - [`AttestationData`](#attestationdata) From d282a36c63d51b1db2fe65dc98e75be173858c1f Mon Sep 17 00:00:00 2001 From: Justin Date: Sat, 26 Jan 2019 19:27:22 +0000 Subject: [PATCH 40/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 9a3590d9a..33226aeee 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1554,7 +1554,7 @@ For each `attestation` in `block.body.attestations`: * Verify bitfields and aggregate signature: ```python - assert attestation.custody_bitfield == 0 # [TO BE REMOVED IN PHASE 1] + assert attestation.custody_bitfield == 0 # [TO BE REMOVED IN PHASE 1] for i in range(len(crosslink_committee)): if get_bitfield_bit(attestation.aggregation_bitfield) == 0: From b1ea3b26674d352861544099dc56d0feabf76790 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sat, 26 Jan 2019 15:27:50 -0700 Subject: [PATCH 41/70] address pr feedback --- specs/core/0_beacon-chain.md | 155 ++++++++++++++++++----------------- 1 file changed, 79 insertions(+), 76 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 57158fdd4..d919ff824 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -61,7 +61,7 @@ - [`hash`](#hash) - [`hash_tree_root`](#hash_tree_root) - [`slot_to_epoch`](#slot_to_epoch) - - [`current_epoch`](#current_epoch) + - [`get_current_epoch`](#get_current_epoch) - [`is_active_validator`](#is_active_validator) - [`get_active_validator_indices`](#get_active_validator_indices) - [`shuffle`](#shuffle) @@ -86,7 +86,7 @@ - [`is_double_vote`](#is_double_vote) - [`is_surround_vote`](#is_surround_vote) - [`integer_squareroot`](#integer_squareroot) - - [`entry_exit_effect_epoch`](#entry_exit_effect_epoch) + - [`get_entry_exit_effect_epoch`](#get_entry_exit_effect_epoch) - [`bls_verify`](#bls_verify) - [`bls_verify_multiple`](#bls_verify_multiple) - [`bls_aggregate_pubkeys`](#bls_aggregate_pubkeys) @@ -192,6 +192,7 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | - | - | | `GENESIS_FORK_VERSION` | `0` | | `GENESIS_SLOT` | `0` | +| `GENESIS_EPOCH` | `slot_to_epoch(GENESIS_SLOT)` | | `GENESIS_START_SHARD` | `0` | | `FAR_FUTURE_EPOCH` | `2**64 - 1` | | `ZERO_HASH` | `int_to_bytes32(0)` | @@ -398,8 +399,8 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be ```python { - # Minimum slot for processing exit - 'slot': 'uint64', + # Minimum epoch for processing exit + 'epoch': 'uint64', # Index of the exiting validator 'validator_index': 'uint24', # Validator signature @@ -569,8 +570,8 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be 'previous_version': 'uint64', # Current fork version 'current_version': 'uint64', - # Fork slot number - 'slot': 'uint64', + # Fork epoch number + 'epoch': 'uint64', } ``` @@ -715,8 +716,8 @@ Beacon block production is significantly different because of the proof of stake The beacon chain fork choice rule is a hybrid that combines justification and finality with Latest Message Driven (LMD) Greediest Heaviest Observed SubTree (GHOST). At any point in time a [validator](#dfn-validator) `v` subjectively calculates the beacon chain head as follows. * Let `store` be the set of attestations and blocks that the [validator](#dfn-validator) `v` has observed and verified (in particular, block ancestors must be recursively verified). Attestations not part of any chain are still included in `store`. -* Let `finalized_head` be the finalized block with the highest slot number. (A block `B` is finalized if there is a descendant of `B` in `store` the processing of which sets `B` as finalized.) -* Let `justified_head` be the descendant of `finalized_head` with the highest slot number that has been justified for at least `EPOCH_LENGTH` slots. (A block `B` is justified if there is a descendant of `B` in `store` the processing of which sets `B` as justified.) If no such descendant exists set `justified_head` to `finalized_head`. +* Let `finalized_head` be the finalized block with the highest epoch. (A block `B` is finalized if there is a descendant of `B` in `store` the processing of which sets `B` as finalized.) +* Let `justified_head` be the descendant of `finalized_head` with the highest epoch that has been justified for at least 1 epoch. (A block `B` is justified if there is a descendant of `B` in `store` the processing of which sets `B` as justified.) If no such descendant exists set `justified_head` to `finalized_head`. * Let `get_ancestor(store, block, slot)` be the ancestor of `block` with slot number `slot`. The `get_ancestor` function can be defined recursively as `def get_ancestor(store, block, slot): return block if block.slot == slot else get_ancestor(store, store.get_parent(block), slot)`. * Let `get_latest_attestation(store, validator)` be the attestation with the highest slot number in `store` from `validator`. If several such attestations exist, use the one the [validator](#dfn-validator) `v` observed first. * Let `get_latest_attestation_target(store, validator)` be the target block in the attestation `get_latest_attestation(store, validator)`. @@ -726,7 +727,7 @@ The beacon chain fork choice rule is a hybrid that combines justification and fi def lmd_ghost(store, start): validators = start.state.validator_registry active_validators = [validators[i] for i in - get_active_validator_indices(validators, current_epoch(start.state))] + get_active_validator_indices(validators, get_current_epoch(start.state))] attestation_targets = [get_latest_attestation_target(store, validator) for validator in active_validators] def get_vote_count(block): @@ -771,10 +772,10 @@ def slot_to_epoch(slot: int) -> int: return slot // EPOCH_LENGTH ``` -#### `current_epoch` +#### `get_current_epoch` ```python -def current_epoch(state: BeaconState) -> int: +def get_current_epoch(state: BeaconState) -> int: return slot_to_epoch(state.slot) ``` @@ -902,7 +903,7 @@ def get_shuffling(seed: Bytes32, return split(shuffled_active_validator_indices, committees_per_slot * EPOCH_LENGTH) ``` -**Invariant**: if `get_shuffling(seed, validators, epoch)` returns some value `x` for some `epoch <= current_epoch(state) + ENTRY_EXIT_DELAY`, it should return the same value `x` for the same `seed` and `epoch` and possible future modifications of `validators` forever in phase 0, and until the ~1 year deletion delay in phase 2 and in the future. +**Invariant**: if `get_shuffling(seed, validators, epoch)` returns some value `x` for some `epoch <= get_current_epoch(state) + ENTRY_EXIT_DELAY`, it should return the same value `x` for the same `seed` and `epoch` and possible future modifications of `validators` forever in phase 0, and until the ~1 year deletion delay in phase 2 and in the future. **Note**: this definition and the next few definitions make heavy use of repetitive computing. Production implementations are expected to appropriately use caching/memoization to avoid redoing work. @@ -936,7 +937,7 @@ def get_crosslink_committees_at_slot(state: BeaconState, """ Returns the list of ``(committee, shard)`` tuples for the ``slot``. """ - current_epoch_slot = current_epoch(state) * EPOCH_LENGTH + current_epoch_slot = get_current_epoch(state) * EPOCH_LENGTH assert current_epoch_slot <= slot + EPOCH_LENGTH assert slot < current_epoch_slot + EPOCH_LENGTH @@ -1004,10 +1005,10 @@ def get_randao_mix(state: BeaconState, def get_active_index_root(state: BeaconState, epoch: int) -> Bytes32: """ - Returns the index root at a recent ``slot``. + Returns the index root at a recent ``epoch``. """ - assert current_epoch(state) < epoch + LATEST_INDEX_ROOTS_LENGTH - assert epoch <= current_epoch(state) + assert get_current_epoch(state) < epoch + LATEST_INDEX_ROOTS_LENGTH + assert epoch <= get_current_epoch(state) return state.latest_index_roots[epoch % LATEST_INDEX_ROOTS_LENGTH] ``` @@ -1100,8 +1101,8 @@ def get_effective_balance(state: State, index: int) -> int: ```python def get_fork_version(fork: Fork, - slot: int) -> int: - if slot < fork.slot: + epoch: int) -> int: + if epoch < fork.epoch: return fork.previous_version else: return fork.current_version @@ -1111,11 +1112,11 @@ def get_fork_version(fork: Fork, ```python def get_domain(fork: Fork, - slot: int, + epoch: int, domain_type: int) -> int: return get_fork_version( fork, - slot + epoch, ) * 2**32 + domain_type ``` @@ -1138,7 +1139,7 @@ def verify_slashable_vote_data(state: BeaconState, vote_data: SlashableVoteData) signature=vote_data.aggregate_signature, domain=get_domain( state.fork, - vote_data.data.slot, + slot_to_epoch(vote_data.data.slot), DOMAIN_ATTESTATION, ), ) @@ -1198,10 +1199,10 @@ def integer_squareroot(n: int) -> int: return x ``` -#### `entry_exit_effect_epoch` +#### `get_entry_exit_effect_epoch` ```python -def entry_exit_effect_epoch(epoch: int) -> int: +def get_entry_exit_effect_epoch(epoch: int) -> int: """ An entry or exit triggered in the ``epoch`` given by the input takes effect at the epoch given by the output. @@ -1255,7 +1256,6 @@ A valid block with slot `GENESIS_SLOT` (a "genesis block") has the following val def get_initial_beacon_state(initial_validator_deposits: List[Deposit], genesis_time: int, latest_eth1_data: Eth1Data) -> BeaconState: - genesis_epoch = slot_to_epoch(GENESIS_SLOT) state = BeaconState( # Misc slot=GENESIS_SLOT, @@ -1263,13 +1263,13 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], fork=Fork( previous_version=GENESIS_FORK_VERSION, current_version=GENESIS_FORK_VERSION, - slot=GENESIS_SLOT, + epoch=GENESIS_EPOCH, ), # Validator registry validator_registry=[], validator_balances=[], - validator_registry_update_epoch=genesis_epoch, + validator_registry_update_epoch=GENESIS_EPOCH, validator_registry_exit_count=0, # Randomness and committees @@ -1277,8 +1277,8 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], latest_vdf_outputs=[ZERO_HASH for _ in range(LATEST_RANDAO_MIXES_LENGTH // EPOCH_LENGTH)], previous_epoch_start_shard=GENESIS_START_SHARD, current_epoch_start_shard=GENESIS_START_SHARD, - previous_calculation_epoch=genesis_epoch, - current_calculation_epoch=genesis_epoch, + previous_calculation_epoch=GENESIS_EPOCH, + current_calculation_epoch=GENESIS_EPOCH, previous_epoch_seed=ZERO_HASH, current_epoch_seed=ZERO_HASH, @@ -1286,13 +1286,13 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], custody_challenges=[], # Finality - previous_justified_epoch=genesis_epoch, - justified_epoch=genesis_epoch, + previous_justified_epoch=GENESIS_EPOCH, + justified_epoch=GENESIS_EPOCH, justification_bitfield=0, - finalized_epoch=genesis_epoch, + finalized_epoch=GENESIS_EPOCH, # Recent state - latest_crosslinks=[Crosslink(epoch=genesis_epoch, shard_block_root=ZERO_HASH) for _ in range(SHARD_COUNT)], + latest_crosslinks=[Crosslink(epoch=GENESIS_EPOCH, shard_block_root=ZERO_HASH) for _ in range(SHARD_COUNT)], latest_block_roots=[ZERO_HASH for _ in range(LATEST_BLOCK_ROOTS_LENGTH)], latest_index_roots=[ZERO_HASH for _ in range(LATEST_INDEX_ROOTS_LENGTH)], latest_penalized_balances=[0 for _ in range(LATEST_PENALIZED_EXIT_LENGTH)], @@ -1319,8 +1319,8 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], if get_effective_balance(state, validator_index) >= MAX_DEPOSIT_AMOUNT: activate_validator(state, validator_index, True) - state.latest_index_roots[genesis_epoch % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, genesis_epoch)) - state.current_epoch_seed = generate_seed(state, genesis_epoch) + state.latest_index_roots[GENESIS_EPOCH % LATEST_INDEX_ROOTS_LENGTH] = hash_tree_root(get_active_validator_indices(state, GENESIS_EPOCH)) + state.current_epoch_seed = generate_seed(state, GENESIS_EPOCH) return state ``` @@ -1346,7 +1346,7 @@ def validate_proof_of_possession(state: BeaconState, signature=proof_of_possession, domain=get_domain( state.fork, - state.slot, + get_current_epoch(state), DOMAIN_DEPOSIT, ) ) @@ -1381,7 +1381,7 @@ def process_deposit(state: BeaconState, withdrawal_credentials=withdrawal_credentials, proposer_slots=0, activation_epoch=FAR_FUTURE_EPOCH, - exit_epch=FAR_FUTURE_EPOCH, + exit_epoch=FAR_FUTURE_EPOCH, withdrawal_epoch=FAR_FUTURE_EPOCH, penalized_epoch=FAR_FUTURE_EPOCH, exit_count=0, @@ -1409,7 +1409,7 @@ Note: All functions in this section mutate `state`. def activate_validator(state: BeaconState, index: int, genesis: bool) -> None: validator = state.validator_registry[index] - validator.activation_epoch = slot_to_epoch(GENESIS_SLOT) if genesis else entry_exit_effect_epoch(current_epoch(state)) + validator.activation_epoch = slot_to_epoch(GENESIS_SLOT) if genesis else get_entry_exit_effect_epoch(get_current_epoch(state)) ``` ```python @@ -1423,10 +1423,10 @@ def exit_validator(state: BeaconState, index: int) -> None: validator = state.validator_registry[index] # The following updates only occur if not previous exited - if validator.exit_epoch <= entry_exit_effect_epoch(current_epoch(state)): + if validator.exit_epoch <= get_entry_exit_effect_epoch(get_current_epoch(state)): return - validator.exit_epoch = entry_exit_effect_epoch(current_epoch(state)) + validator.exit_epoch = get_entry_exit_effect_epoch(get_current_epoch(state)) state.validator_registry_exit_count += 1 validator.exit_count = state.validator_registry_exit_count @@ -1436,13 +1436,13 @@ def exit_validator(state: BeaconState, index: int) -> None: def penalize_validator(state: BeaconState, index: int) -> None: exit_validator(state, index) validator = state.validator_registry[index] - state.latest_penalized_balances[current_epoch(state) % LATEST_PENALIZED_EXIT_LENGTH] += get_effective_balance(state, index) + state.latest_penalized_balances[get_current_epoch(state) % LATEST_PENALIZED_EXIT_LENGTH] += get_effective_balance(state, index) whistleblower_index = get_beacon_proposer_index(state, state.slot) whistleblower_reward = get_effective_balance(state, index) // WHISTLEBLOWER_REWARD_QUOTIENT state.validator_balances[whistleblower_index] += whistleblower_reward state.validator_balances[index] -= whistleblower_reward - validator.penalized_epoch = current_epoch(state) + validator.penalized_epoch = get_current_epoch(state) ``` ```python @@ -1459,7 +1459,7 @@ Below are the processing steps that happen at every slot. * Set `state.slot += 1`. * Set `state.validator_registry[get_beacon_proposer_index(state, state.slot)].proposer_slots += 1`. -* Set `state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH] = state.latest_randao_mixes[(state.slot - 1) % LATEST_RANDAO_MIXES_LENGTH]` +* Set `state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH] = get_randao_mix(state, state.slot - 1)`. ### Block roots @@ -1479,13 +1479,13 @@ Below are the processing steps that happen at every `block`. * Let `block_without_signature_root` be the `hash_tree_root` of `block` where `block.signature` is set to `EMPTY_SIGNATURE`. * Let `proposal_root = hash_tree_root(ProposalSignedData(state.slot, BEACON_CHAIN_SHARD_NUMBER, block_without_signature_root))`. -* Verify that `bls_verify(pubkey=state.validator_registry[get_beacon_proposer_index(state, state.slot)].pubkey, message=proposal_root, signature=block.signature, domain=get_domain(state.fork, state.slot, DOMAIN_PROPOSAL))`. +* Verify that `bls_verify(pubkey=state.validator_registry[get_beacon_proposer_index(state, state.slot)].pubkey, message=proposal_root, signature=block.signature, domain=get_domain(state.fork, get_current_epoch(state), DOMAIN_PROPOSAL))`. ### RANDAO * Let `proposer = state.validator_registry[get_beacon_proposer_index(state, state.slot)]`. -* Verify that `bls_verify(pubkey=proposer.pubkey, message=int_to_bytes32(proposer.proposer_slots), signature=block.randao_reveal, domain=get_domain(state.fork, state.slot, DOMAIN_RANDAO))`. -* Set `state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH] = hash(state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH] + block.randao_reveal)`. +* Verify that `bls_verify(pubkey=proposer.pubkey, message=int_to_bytes32(proposer.proposer_slots), signature=block.randao_reveal, domain=get_domain(state.fork, get_current_epoch(state), DOMAIN_RANDAO))`. +* Set `state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH] = hash(get_randao_mix(state, state.slot) + block.randao_reveal)`. ### Eth1 data @@ -1504,9 +1504,9 @@ For each `proposer_slashing` in `block.body.proposer_slashings`: * Verify that `proposer_slashing.proposal_data_1.slot == proposer_slashing.proposal_data_2.slot`. * Verify that `proposer_slashing.proposal_data_1.shard == proposer_slashing.proposal_data_2.shard`. * Verify that `proposer_slashing.proposal_data_1.block_root != proposer_slashing.proposal_data_2.block_root`. -* Verify that `proposer.penalized_epoch > current_epoch(state)`. -* Verify that `bls_verify(pubkey=proposer.pubkey, message=hash_tree_root(proposer_slashing.proposal_data_1), signature=proposer_slashing.proposal_signature_1, domain=get_domain(state.fork, proposer_slashing.proposal_data_1.slot, DOMAIN_PROPOSAL))`. -* Verify that `bls_verify(pubkey=proposer.pubkey, message=hash_tree_root(proposer_slashing.proposal_data_2), signature=proposer_slashing.proposal_signature_2, domain=get_domain(state.fork, proposer_slashing.proposal_data_2.slot, DOMAIN_PROPOSAL))`. +* Verify that `proposer.penalized_epoch > get_current_epoch(state)`. +* Verify that `bls_verify(pubkey=proposer.pubkey, message=hash_tree_root(proposer_slashing.proposal_data_1), signature=proposer_slashing.proposal_signature_1, domain=get_domain(state.fork, slot_to_epoch(proposer_slashing.proposal_data_1.slot), DOMAIN_PROPOSAL))`. +* Verify that `bls_verify(pubkey=proposer.pubkey, message=hash_tree_root(proposer_slashing.proposal_data_2), signature=proposer_slashing.proposal_signature_2, domain=get_domain(state.fork, slot_to_epoch(proposer_slashing.proposal_data_2.slot), DOMAIN_PROPOSAL))`. * Run `penalize_validator(state, proposer_slashing.proposer_index)`. #### Casper slashings @@ -1524,7 +1524,7 @@ For each `casper_slashing` in `block.body.casper_slashings`: * Verify that `is_double_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)` or `is_surround_vote(slashable_vote_data_1.data, slashable_vote_data_2.data)`. * Verify that `verify_slashable_vote_data(state, slashable_vote_data_1)`. * Verify that `verify_slashable_vote_data(state, slashable_vote_data_2)`. -* For each [validator](#dfn-validator) index `i` in `intersection` run `penalize_validator(state, i)` if `state.validator_registry[i].penalized_epoch > current_epoch(state)`. +* For each [validator](#dfn-validator) index `i` in `intersection` run `penalize_validator(state, i)` if `state.validator_registry[i].penalized_epoch > get_current_epoch(state)`. #### Attestations @@ -1540,7 +1540,7 @@ For each `attestation` in `block.body.attestations`: * `aggregate_signature` verification: * Let `participants = get_attestation_participants(state, attestation.data, attestation.aggregation_bitfield)`. * Let `group_public_key = bls_aggregate_pubkeys([state.validator_registry[v].pubkey for v in participants])`. - * Verify that `bls_verify(pubkey=group_public_key, message=hash_tree_root(AttestationDataAndCustodyBit(attestation.data, False)), signature=attestation.aggregate_signature, domain=get_domain(state.fork, attestation.data.slot, DOMAIN_ATTESTATION))`. + * Verify that `bls_verify(pubkey=group_public_key, message=hash_tree_root(AttestationDataAndCustodyBit(attestation.data, False)), signature=attestation.aggregate_signature, domain=get_domain(state.fork, slot_to_epoch(attestation.data.slot), DOMAIN_ATTESTATION))`. * [TO BE REMOVED IN PHASE 1] Verify that `attestation.data.shard_block_root == ZERO_HASH`. * Append `PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, custody_bitfield=attestation.custody_bitfield, slot_included=state.slot)` to `state.latest_attestations`. @@ -1586,10 +1586,10 @@ Verify that `len(block.body.exits) <= MAX_EXITS`. For each `exit` in `block.body.exits`: * Let `validator = state.validator_registry[exit.validator_index]`. -* Verify that `validator.exit_epoch > entry_exit_effect_epoch(current_epoch(state))`. -* Verify that `state.slot >= exit.slot`. -* Let `exit_message = hash_tree_root(Exit(slot=exit.slot, validator_index=exit.validator_index, signature=EMPTY_SIGNATURE))`. -* Verify that `bls_verify(pubkey=validator.pubkey, message=exit_message, signature=exit.signature, domain=get_domain(state.fork, exit.slot, DOMAIN_EXIT))`. +* Verify that `validator.exit_epoch > get_entry_exit_effect_epoch(get_current_epoch(state))`. +* Verify that `get_current_epoch(state) >= exit.epoch`. +* Let `exit_message = hash_tree_root(Exit(epoch=exit.epoch, validator_index=exit.validator_index, signature=EMPTY_SIGNATURE))`. +* Verify that `bls_verify(pubkey=validator.pubkey, message=exit_message, signature=exit.signature, domain=get_domain(state.fork, exit.epoch, DOMAIN_EXIT))`. * Run `initiate_validator_exit(state, exit.validator_index)`. #### Custody @@ -1602,15 +1602,16 @@ The steps below happen when `(state.slot + 1) % EPOCH_LENGTH == 0`. ### Helpers -* Let `current_epoch_start_slot = current_epoch(state) * EPOCH_LENGTH`. -* Let `next_epoch = current_epoch(state) + 1`. -* Let `next_epoch_start_slot = next_epoch * EPOCH_LENGTH`. -* Let `previous_epoch = current_epoch(state) - 1 if current_epoch(state) > slot_to_epoch(GENESIS_SLOT) else current_epoch(state)`. +* Let `current_epoch = get_current_epoch(state)`. +* Let `current_epoch_start_slot = current_epoch * EPOCH_LENGTH`. +* Let `previous_epoch = current_epoch - 1 if current_epoch > slot_to_epoch(GENESIS_SLOT) else current_epoch`. * Let `previous_epoch_start_slot = previous_epoch * EPOCH_LENGTH`. +* Let `next_epoch = current_epoch + 1`. +* Let `next_epoch_start_slot = next_epoch * EPOCH_LENGTH`. All [validators](#dfn-validator): -* Let `active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch(state))`. +* Let `active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch)`. * Let `total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices])`. [Validators](#dfn-Validator) attesting during the current epoch: @@ -1657,7 +1658,7 @@ Define the following helpers to process attestation inclusion rewards and inclus ### Eth1 data -If `current_epoch(state) % ETH1_DATA_VOTING_PERIOD == 0`: +If `current_epoch % ETH1_DATA_VOTING_PERIOD == 0`: * Set `state.latest_eth1_data = eth1_data_vote.data` if `eth1_data_vote.vote_count * 2 > ETH1_DATA_VOTING_PERIOD * EPOCH_LENGTH` for some `eth1_data_vote` in `state.eth1_data_votes`. * Set `state.eth1_data_votes = []`. @@ -1669,7 +1670,7 @@ First, update the justification bitfield: * Let `new_justified_epoch = state.justified_epoch`. * Set `state.justification_bitfield = (state.justification_bitfield * 2) % 2**64`. * Set `state.justification_bitfield |= 2` and `new_justified_epoch = previous_epoch` if `3 * previous_epoch_boundary_attesting_balance >= 2 * total_balance`. -* Set `state.justification_bitfield |= 1` and `new_justified_epoch = current_epoch(state)` if `3 * current_epoch_boundary_attesting_balance >= 2 * total_balance`. +* Set `state.justification_bitfield |= 1` and `new_justified_epoch = current_epoch` if `3 * current_epoch_boundary_attesting_balance >= 2 * total_balance`. Next, update last finalized slot if possible: @@ -1687,7 +1688,7 @@ Finally, update the following: For every `slot in range(previous_epoch_start_slot, next_epoch_start_slot)`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: -* Set `state.latest_crosslinks[shard] = Crosslink(epoch=current_epoch(state), shard_block_root=winning_root(crosslink_committee))` if `3 * total_attesting_balance(crosslink_committee) >= 2 * total_balance(crosslink_committee)`. +* Set `state.latest_crosslinks[shard] = Crosslink(epoch=current_epoch, shard_block_root=winning_root(crosslink_committee))` if `3 * total_attesting_balance(crosslink_committee) >= 2 * total_balance(crosslink_committee)`. ### Rewards and penalties @@ -1722,7 +1723,7 @@ Case 2: `epochs_since_finality > 4`: * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_justified_attester_indices`, loses `inactivity_penalty(state, index, epochs_since_finality)`. * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_boundary_attester_indices`, loses `inactivity_penalty(state, index, epochs_since_finality)`. * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_head_attester_indices`, loses `base_reward(state, index)`. -* Any [active_validator](#dfn-active-validator) `index` with `validator.penalized_epoch <= current_epoch(state)`, loses `2 * inactivity_penalty(state, index, epochs_since_finality) + base_reward(state, index)`. +* Any [active_validator](#dfn-active-validator) `index` with `validator.penalized_epoch <= current_epoch`, loses `2 * inactivity_penalty(state, index, epochs_since_finality) + base_reward(state, index)`. * Any [validator](#dfn-validator) `index` in `previous_epoch_attester_indices` loses `base_reward(state, index) - base_reward(state, index) * MIN_ATTESTATION_INCLUSION_DELAY // inclusion_distance(state, index)` #### Attestation inclusion @@ -1773,8 +1774,9 @@ def update_validator_registry(state: BeaconState) -> None: Update validator registry. Note that this function mutates ``state``. """ + current_epoch = get_current_epoch(state) # The active validators - active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch(state)) + active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch) # The total effective balance of active validators total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices]) @@ -1787,7 +1789,7 @@ def update_validator_registry(state: BeaconState) -> None: # Activate validators within the allowable balance churn balance_churn = 0 for index, validator in enumerate(state.validator_registry): - if validator.activation_epoch > entry_exit_effect_epoch(current_epoch(state)) and state.validator_balances[index] >= MAX_DEPOSIT_AMOUNT: + if validator.activation_epoch > get_entry_exit_effect_epoch(current_epoch) and state.validator_balances[index] >= MAX_DEPOSIT_AMOUNT: # Check the balance churn would be within the allowance balance_churn += get_effective_balance(state, index) if balance_churn > max_balance_churn: @@ -1799,7 +1801,7 @@ def update_validator_registry(state: BeaconState) -> None: # Exit validators within the allowable balance churn balance_churn = 0 for index, validator in enumerate(state.validator_registry): - if validator.exit_epoch > entry_exit_effect_epoch(current_epoch(state)) and validator.status_flags & INITIATED_EXIT: + if validator.exit_epoch > get_entry_exit_effect_epoch(current_epoch) and validator.status_flags & INITIATED_EXIT: # Check the balance churn would be within the allowance balance_churn += get_effective_balance(state, index) if balance_churn > max_balance_churn: @@ -1808,7 +1810,7 @@ def update_validator_registry(state: BeaconState) -> None: # Exit validator exit_validator(state, index) - state.validator_registry_update_epoch = current_epoch(state) + state.validator_registry_update_epoch = current_epoch ``` and perform the following updates: @@ -1819,7 +1821,7 @@ and perform the following updates: If a validator registry update does _not_ happen do the following: -* Let `epochs_since_last_registry_change = current_epoch(state) - state.validator_registry_update_epoch`. +* Let `epochs_since_last_registry_change = current_epoch - state.validator_registry_update_epoch`. * If `epochs_since_last_registry_change` is an exact power of 2: * Set `state.current_calculation_epoch = next_epoch`. * Set `state.current_epoch_seed = generate_seed(state, state.current_calculation_epoch)` @@ -1831,14 +1833,15 @@ Regardless of whether or not a validator set change happens, run the following: ```python def process_penalties_and_exits(state: BeaconState) -> None: + current_epoch = get_current_epoch(state) # The active validators - active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch(state)) + active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch) # The total effective balance of active validators total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices]) for index, validator in enumerate(state.validator_registry): - if current_epoch(state) == validator.penalized_epoch + LATEST_PENALIZED_EXIT_LENGTH // 2: - e = current_epoch(state) % LATEST_PENALIZED_EXIT_LENGTH + if current_epoch == validator.penalized_epoch + LATEST_PENALIZED_EXIT_LENGTH // 2: + e = current_epoch % LATEST_PENALIZED_EXIT_LENGTH total_at_start = state.latest_penalized_balances[(e + 1) % LATEST_PENALIZED_EXIT_LENGTH] total_at_end = state.latest_penalized_balances[e] total_penalties = total_at_end - total_at_start @@ -1847,11 +1850,11 @@ def process_penalties_and_exits(state: BeaconState) -> None: def eligible(index): validator = state.validator_registry[index] - if validator.penalized_epoch <= current_epoch(state): + if validator.penalized_epoch <= current_epoch: PENALIZED_WITHDRAWAL_EPOCHS = LATEST_PENALIZED_EXIT_LENGTH // 2 - return current_epoch(state) >= validator.penalized_epoch + PENALIZED_WITHDRAWAL_EPOCHS + return current_epoch >= validator.penalized_epoch + PENALIZED_WITHDRAWAL_EPOCHS else: - return current_epoch(state) >= validator.exit_epoch + MIN_VALIDATOR_WITHDRAWAL_EPOCHS + return current_epoch >= validator.exit_epoch + MIN_VALIDATOR_WITHDRAWAL_EPOCHS all_indices = list(range(len(state.validator_registry))) eligible_indices = filter(eligible, all_indices) @@ -1866,8 +1869,8 @@ def process_penalties_and_exits(state: BeaconState) -> None: ### Final updates -* Set `state.latest_penalized_balances[(next_epoch) % LATEST_PENALIZED_EXIT_LENGTH] = state.latest_penalized_balances[current_epoch(state) % LATEST_PENALIZED_EXIT_LENGTH]`. -* Remove any `attestation` in `state.latest_attestations` such that `slot_to_epoch(attestation.data.slot) < current_epoch(state)`. +* Set `state.latest_penalized_balances[(next_epoch) % LATEST_PENALIZED_EXIT_LENGTH] = state.latest_penalized_balances[current_epoch % LATEST_PENALIZED_EXIT_LENGTH]`. +* Remove any `attestation` in `state.latest_attestations` such that `slot_to_epoch(attestation.data.slot) < current_epoch`. ## State root processing From 8da467df7ca72aef010f3130d3bf2f03e2b5ae01 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sat, 26 Jan 2019 15:39:57 -0700 Subject: [PATCH 42/70] pr feedback --- specs/core/0_beacon-chain.md | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index d919ff824..3344d295d 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -937,11 +937,14 @@ def get_crosslink_committees_at_slot(state: BeaconState, """ Returns the list of ``(committee, shard)`` tuples for the ``slot``. """ - current_epoch_slot = get_current_epoch(state) * EPOCH_LENGTH - assert current_epoch_slot <= slot + EPOCH_LENGTH - assert slot < current_epoch_slot + EPOCH_LENGTH + epoch = slot_to_epoch(slot) + current_epoch = get_current_epoch(state) + previous_epoch = current_epoch - 1 if epoch > GENESIS_EPOCH else current_epoch + next_epoch = current_epoch + 1 - if slot < current_epoch_slot: + assert previous_epoch <= epoch < next_epoch + + if epoch < current_epoch: committees_per_slot = get_previous_epoch_committee_count_per_slot(state) seed = state.previous_epoch_seed shuffling_epoch = state.previous_calculation_epoch From 82ecc8c86856fc504db96504aa93488f6218510d Mon Sep 17 00:00:00 2001 From: Justin Date: Sun, 27 Jan 2019 09:01:11 +0000 Subject: [PATCH 43/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 48 ++++++++++++++++++------------------ 1 file changed, 24 insertions(+), 24 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 33226aeee..8ac9fb47c 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -261,7 +261,7 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git ```python { # Proposer index - 'proposer_index': 'uint24', + 'proposer_index': 'uint64', # First proposal data 'proposal_data_1': ProposalSignedData, # First proposal signature @@ -291,7 +291,7 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git ```python { # Validator indices - 'validator_indices': '[uint24]', + 'validator_indices': '[uint64]', # Custody bitfield 'custody_bitfield': 'bytes', # Attestation data @@ -402,7 +402,7 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git # Minimum slot for processing exit 'slot': 'uint64', # Index of the exiting validator - 'validator_index': 'uint24', + 'validator_index': 'uint64', # Validator signature 'signature': 'bytes96', } @@ -588,15 +588,15 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git We define the following Python custom types for type hinting and readability: -| Name | Type | Description | +| Name | SSZ equivalent | Description | | - | - | - | -| `SlotNumber` | unsigned 64-bit integer | the number of a slot | -| `ShardNumber` | unsigned 64-bit integer | the number of a shard | -| `ValidatorIndex` | unsigned 24-bit integer | the index number of a validator in the registry | -| `Gwei` | unsigned 64-bit integer | an amount in Gwei | -| `Bytes32` | 32-byte data | binary data with 32-byte length | -| `BLSPubkey` | 48-byte data | a public key in BLS signature scheme | -| `BLSSignature` | 96-byte data | a signature in BLS signature scheme | +| `SlotNumber` | `uint64` | a slot number | +| `ShardNumber` | `uint64` | a shard number | +| `ValidatorIndex` | `uint64` | an index in the validator registry | +| `Gwei` | `uint64` | an amount in Gwei | +| `Bytes32` | `bytes32` | 32 bytes of binary data | +| `BLSPubkey` | `bytes48` | a BLS public key | +| `BLSSignature` | `bytes96` | a BLS signature | ## Ethereum 1.0 deposit contract @@ -1058,7 +1058,7 @@ def get_attestation_participants(state: BeaconState, participants = [] for i, validator_index in enumerate(crosslink_committee): aggregation_bit = get_bitfield_bit(bitfield, i) - if aggregation_bit == 1: + if aggregation_bit == 0b1: participants.append(validator_index) return participants ``` @@ -1121,7 +1121,7 @@ def verify_bitfield(bitfield: bytes, committee_size: int) -> bool: return False for i in range(committee_size + 1, committee_size - committee_size % 8 + 8): - if get_bitfield_bit(bitfield, i) != 0: + if get_bitfield_bit(bitfield, i) == 0b1: return False return True @@ -1142,7 +1142,7 @@ def verify_slashable_vote(state: BeaconState, slashable_vote: SlashableVote) -> for i in range(len(slashable_vote.validator_indices) - 1): if slashable_vote.validator_indices[i] >= slashable_vote.validator_indices[i + 1]: - return False + return False if not verify_bitfield(slashable_vote.custody_bitfield, len(slashable_vote.validator_indices)): return False @@ -1153,7 +1153,7 @@ def verify_slashable_vote(state: BeaconState, slashable_vote: SlashableVote) -> custody_bit_0_indices = [] custody_bit_1_indices = [] for i, validator_index in enumerate(slashable_vote.validator_indices): - if get_bitfield_bit(slashable_vote.custody_bitfield, i) == 0: + if get_bitfield_bit(slashable_vote.custody_bitfield, i) == 0b0: custody_bit_0_indices.append(validator_index) else: custody_bit_1_indices.append(validator_index) @@ -1164,8 +1164,8 @@ def verify_slashable_vote(state: BeaconState, slashable_vote: SlashableVote) -> bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in custody_bit_1_indices]), ], messages=[ - hash_tree_root(AttestationDataAndCustodyBit(slashable_vote.data, 0)), - hash_tree_root(AttestationDataAndCustodyBit(slashable_vote.data, 1)), + hash_tree_root(AttestationDataAndCustodyBit(attestation_data=slashable_vote.data, custody_bit=0b0)), + hash_tree_root(AttestationDataAndCustodyBit(attestation_data=slashable_vote.data, custody_bit=0b1)), ], signature=slashable_vote.aggregate_signature, domain=get_domain(state.fork, slashable_vote.data.slot, DOMAIN_ATTESTATION), @@ -1554,15 +1554,15 @@ For each `attestation` in `block.body.attestations`: * Verify bitfields and aggregate signature: ```python - assert attestation.custody_bitfield == 0 # [TO BE REMOVED IN PHASE 1] + assert attestation.custody_bitfield == b'\x00' * len(attestation.custody_bitfield) # [TO BE REMOVED IN PHASE 1] for i in range(len(crosslink_committee)): - if get_bitfield_bit(attestation.aggregation_bitfield) == 0: - assert get_bitfield_bit(attestation.custody_bitfield) == 0 + if get_bitfield_bit(attestation.aggregation_bitfield) == 0b0: + assert get_bitfield_bit(attestation.custody_bitfield) == 0b0 participants = get_attestation_participants(state, attestation.data, attestation.aggregation_bitfield) - custody_bit_0_participants = get_attestation_participants(state, attestation.data, attestation.custody_bitfield) - custody_bit_1_participants = [i in participants for i not in custody_bit_0_participants] + custody_bit_1_participants = get_attestation_participants(state, attestation.data, attestation.custody_bitfield) + custody_bit_0_participants = [i in participants for i not in custody_bit_1_participants] assert bls_verify_multiple( pubkeys=[ @@ -1570,8 +1570,8 @@ For each `attestation` in `block.body.attestations`: bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in custody_bit_1_participants]), ], messages=[ - hash_tree_root(AttestationDataAndCustodyBit(data=attestation.data, custody_bit=0)), - hash_tree_root(AttestationDataAndCustodyBit(data=attestation.data, custody_bit=1)), + hash_tree_root(AttestationDataAndCustodyBit(data=attestation.data, custody_bit=0b0)), + hash_tree_root(AttestationDataAndCustodyBit(data=attestation.data, custody_bit=0b1)), ], signature=attestation.aggregate_signature, domain=get_domain(state.fork, attestation.data.slot, DOMAIN_ATTESTATION), From e1e1e2359a46e46c19ab7f68c92f70e94704ff49 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sun, 27 Jan 2019 07:54:46 -0700 Subject: [PATCH 44/70] pr feedback --- specs/core/0_beacon-chain.md | 40 ++++++++++++++++++++---------------- 1 file changed, 22 insertions(+), 18 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 225c7addc..97e7a7dd1 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -63,6 +63,7 @@ - [`hash_tree_root`](#hash_tree_root) - [`slot_to_epoch`](#slot_to_epoch) - [`get_current_epoch`](#get_current_epoch) + - [`get_epoch_start_slot`](#get_epoch_start_slot) - [`is_active_validator`](#is_active_validator) - [`get_active_validator_indices`](#get_active_validator_indices) - [`shuffle`](#shuffle) @@ -794,17 +795,23 @@ Note: We aim to migrate to a S[T/N]ARK-friendly hash function in a future Ethere #### `slot_to_epoch` ```python -def slot_to_epoch(slot: int) -> int: +def slot_to_epoch(slot: SlotNumber) -> EpochNumber: return slot // EPOCH_LENGTH ``` #### `get_current_epoch` ```python -def get_current_epoch(state: BeaconState) -> int: +def get_current_epoch(state: BeaconState) -> EpochNumber: return slot_to_epoch(state.slot) ``` +#### `get_epoch_start_slot` + +```python +def get_epoch_start_slot(epoch: EpochNumber) -> SlotNumber: + return slot_to_epoch(state.slot) +``` #### `is_active_validator` ```python @@ -1050,12 +1057,12 @@ def generate_seed(state: BeaconState, Generate a seed for the given ``epoch``. """ if epoch < SEED_LOOKAHEAD: - randao_mix_epoch = slot_to_epoch(GENESIS_SLOT) + randao_mix_epoch = GENESIS_EPOCH else: randao_mix_epoch = epoch - SEED_LOOKAHEAD return hash( - get_randao_mix(state, randao_mix_epoch * EPOCH_LENGTH) + + get_randao_mix(state, get_epoch_start_slot(randao_mix_epoch)) + get_active_index_root(state, epoch) ) @@ -1437,7 +1444,7 @@ Note: All functions in this section mutate `state`. def activate_validator(state: BeaconState, index: ValidatorIndex, genesis: bool) -> None: validator = state.validator_registry[index] - validator.activation_epoch = slot_to_epoch(GENESIS_SLOT) if genesis else get_entry_exit_effect_epoch(get_current_epoch(state)) + validator.activation_epoch = GENESIS_EPOCH if genesis else get_entry_exit_effect_epoch(get_current_epoch(state)) ``` ```python @@ -1562,7 +1569,7 @@ For each `attestation` in `block.body.attestations`: * Verify that `attestation.data.slot + MIN_ATTESTATION_INCLUSION_DELAY <= state.slot`. * Verify that `attestation.data.slot + EPOCH_LENGTH >= state.slot`. * Verify that `attestation.data.justified_epoch` is equal to `state.justified_epoch if attestation.data.slot >= state.slot - (state.slot % EPOCH_LENGTH) else state.previous_justified_epoch`. -* Verify that `attestation.data.justified_block_root` is equal to `get_block_root(state, attestation.data.justified_epoch * EPOCH_LENGTH)`. +* Verify that `attestation.data.justified_block_root` is equal to `get_block_root(state, get_epoch_start_slot(attestation.data.justified_epoch))`. * Verify that either `attestation.data.latest_crosslink_root` or `attestation.data.shard_block_root` equals `state.latest_crosslinks[shard].shard_block_root`. * `aggregate_signature` verification: * Let `participants = get_attestation_participants(state, attestation.data, attestation.aggregation_bitfield)`. @@ -1630,11 +1637,8 @@ The steps below happen when `(state.slot + 1) % EPOCH_LENGTH == 0`. ### Helpers * Let `current_epoch = get_current_epoch(state)`. -* Let `current_epoch_start_slot = current_epoch * EPOCH_LENGTH`. -* Let `previous_epoch = current_epoch - 1 if current_epoch > slot_to_epoch(GENESIS_SLOT) else current_epoch`. -* Let `previous_epoch_start_slot = previous_epoch * EPOCH_LENGTH`. +* Let `previous_epoch = current_epoch - 1 if current_epoch > GENESIS_EPOCH else current_epoch`. * Let `next_epoch = current_epoch + 1`. -* Let `next_epoch_start_slot = next_epoch * EPOCH_LENGTH`. All [validators](#dfn-validator): @@ -1643,23 +1647,23 @@ All [validators](#dfn-validator): [Validators](#dfn-Validator) attesting during the current epoch: -* Let `current_epoch_attestations = [a for a in state.latest_attestations if current_epoch_start_slot <= a.data.slot < next_epoch_start_slot]`. (Note: this is the set of attestations of slots in the epoch `current_epoch_start_slot...next_epoch_start_slot`, _not_ attestations that got included in the chain during the epoch `current_epoch_start_slot...next_epoch_start_slot`.) +* Let `current_epoch_attestations = [a for a in state.latest_attestations if current_epoch == slot_to_epoch(a.data.slot)]`. (Note: this is the set of attestations of slots in the epoch `current_epoch`, _not_ attestations that got included in the chain during the epoch `current_epoch`.) * Validators justifying the epoch boundary block at the start of the current epoch: - * Let `current_epoch_boundary_attestations = [a for a in current_epoch_attestations if a.data.epoch_boundary_root == get_block_root(state, current_epoch_start_slot) and a.data.justified_epoch == state.justified_epoch]`. + * Let `current_epoch_boundary_attestations = [a for a in current_epoch_attestations if a.data.epoch_boundary_root == get_block_root(state, get_epoch_start_slot(current_epoch)) and a.data.justified_epoch == state.justified_epoch]`. * Let `current_epoch_boundary_attester_indices` be the union of the [validator](#dfn-validator) index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in current_epoch_boundary_attestations]`. * Let `current_epoch_boundary_attesting_balance = sum([get_effective_balance(state, i) for i in current_epoch_boundary_attester_indices])`. [Validators](#dfn-Validator) attesting during the previous epoch: * Validators that made an attestation during the previous epoch: - * Let `previous_epoch_attestations = [a for a in state.latest_attestations if previous_epoch_start_slot <= a.data.slot < current_epoch_start_slot]`. + * Let `previous_epoch_attestations = [a for a in state.latest_attestations if previous_epoch == slot_to_epoch(a.data.slot)]`. * Let `previous_epoch_attester_indices` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in previous_epoch_attestations]`. * Validators targeting the previous justified slot: * Let `previous_epoch_justified_attestations = [a for a in current_epoch_attestations + previous_epoch_attestations if a.data.justified_epoch == state.previous_justified_epoch]`. * Let `previous_epoch_justified_attester_indices` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in previous_epoch_justified_attestations]`. * Let `previous_epoch_justified_attesting_balance = sum([get_effective_balance(state, i) for i in previous_epoch_justified_attester_indices])`. * Validators justifying the epoch boundary block at the start of the previous epoch: - * Let `previous_epoch_boundary_attestations = [a for a in previous_epoch_justified_attestations if a.data.epoch_boundary_root == get_block_root(state, previous_epoch_start_slot)]`. + * Let `previous_epoch_boundary_attestations = [a for a in previous_epoch_justified_attestations if a.data.epoch_boundary_root == get_block_root(state, get_epoch_start_slot(previous_epoch))]`. * Let `previous_epoch_boundary_attester_indices` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in previous_epoch_boundary_attestations]`. * Let `previous_epoch_boundary_attesting_balance = sum([get_effective_balance(state, i) for i in previous_epoch_boundary_attester_indices])`. * Validators attesting to the expected beacon chain head during the previous epoch: @@ -1669,7 +1673,7 @@ All [validators](#dfn-validator): **Note**: `previous_epoch_boundary_attesting_balance` balance might be marginally different than `current_epoch_boundary_attesting_balance` during the previous epoch transition. Due to the tight bound on validator churn each epoch and small per-epoch rewards/penalties, the potential balance difference is very low and only marginally affects consensus safety. -For every `slot in range(previous_epoch_start_slot, next_epoch_start_slot)`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: +For every `slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_slot(next_epoch))`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: * Let `shard_block_root` be `state.latest_crosslinks[shard].shard_block_root` * Let `attesting_validator_indices(crosslink_committee, shard_block_root)` be the union of the [validator](#dfn-validator) index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in current_epoch_attestations + previous_epoch_attestations if a.data.shard == shard and a.data.shard_block_root == shard_block_root]`. @@ -1699,7 +1703,7 @@ First, update the justification bitfield: * Set `state.justification_bitfield |= 2` and `new_justified_epoch = previous_epoch` if `3 * previous_epoch_boundary_attesting_balance >= 2 * total_balance`. * Set `state.justification_bitfield |= 1` and `new_justified_epoch = current_epoch` if `3 * current_epoch_boundary_attesting_balance >= 2 * total_balance`. -Next, update last finalized slot if possible: +Next, update last finalized epoch if possible: * Set `state.finalized_epoch = state.previous_justified_epoch` if `(state.justification_bitfield >> 1) % 8 == 0b111 and state.previous_justified_epoch == previous_epoch - 2`. * Set `state.finalized_epoch = state.previous_justified_epoch` if `(state.justification_bitfield >> 1) % 4 == 0b11 and state.previous_justified_epoch == previous_epoch - 1`. @@ -1713,7 +1717,7 @@ Finally, update the following: ### Crosslinks -For every `slot in range(previous_epoch_start_slot, next_epoch_start_slot)`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: +For every `slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_slot(next_epoch))`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: * Set `state.latest_crosslinks[shard] = Crosslink(epoch=current_epoch, shard_block_root=winning_root(crosslink_committee))` if `3 * total_attesting_balance(crosslink_committee) >= 2 * total_balance(crosslink_committee)`. @@ -1759,7 +1763,7 @@ For each `index` in `previous_epoch_attester_indices`, we determine the proposer #### Crosslinks -For every `slot in range(previous_epoch_start_slot, current_epoch_start_slot)`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: +For every `slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_slot(current_epoch))`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: * If `index in attesting_validators(crosslink_committee)`, `state.validator_balances[index] += base_reward(state, index) * total_attesting_balance(crosslink_committee) // total_balance(crosslink_committee))`. * If `index not in attesting_validators(crosslink_committee)`, `state.validator_balances[index] -= base_reward(state, index)`. From 9d18760521ae05c1edfd0ca6a1fb104c02506af9 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sun, 27 Jan 2019 09:56:26 -0700 Subject: [PATCH 45/70] convert some functions to be per epoch --- specs/core/0_beacon-chain.md | 39 ++++++++++++++++++------------------ 1 file changed, 20 insertions(+), 19 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 97e7a7dd1..2ead71784 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -68,10 +68,10 @@ - [`get_active_validator_indices`](#get_active_validator_indices) - [`shuffle`](#shuffle) - [`split`](#split) - - [`get_committee_count_per_slot`](#get_committee_count_per_slot) + - [`get_epoch_committee_count`](#get_epoch_committee_count) - [`get_shuffling`](#get_shuffling) - - [`get_previous_epoch_committee_count_per_slot`](#get_previous_epoch_committee_count_per_slot) - - [`get_current_epoch_committee_count_per_slot`](#get_current_epoch_committee_count_per_slot) + - [`get_previous_epoch_committee_count`](#get_previous_epoch_committee_count) + - [`get_current_epoch_committee_count`](#get_current_epoch_committee_count) - [`get_crosslink_committees_at_slot`](#get_crosslink_committees_at_slot) - [`get_block_root`](#get_block_root) - [`get_randao_mix`](#get_randao_mix) @@ -899,17 +899,17 @@ def split(values: List[Any], split_count: int) -> List[List[Any]]: ] ``` -#### `get_committee_count_per_slot` +#### `get_epoch_committee_count` ```python -def get_committee_count_per_slot(active_validator_count: int) -> int: +def get_epoch_committee_count(active_validator_count: int) -> int: return max( 1, min( SHARD_COUNT // EPOCH_LENGTH, active_validator_count // EPOCH_LENGTH // TARGET_COMMITTEE_SIZE, ) - ) + ) * EPOCH_LENGTH ``` #### `get_shuffling` @@ -926,40 +926,40 @@ def get_shuffling(seed: Bytes32, active_validator_indices = get_active_validator_indices(validators, epoch) - committees_per_slot = get_committee_count_per_slot(len(active_validator_indices)) + committees_per_epoch = get_epoch_committee_count(len(active_validator_indices)) # Shuffle seed = xor(seed, int_to_bytes32(epoch)) shuffled_active_validator_indices = shuffle(active_validator_indices, seed) - # Split the shuffled list into epoch_length * committees_per_slot pieces - return split(shuffled_active_validator_indices, committees_per_slot * EPOCH_LENGTH) + # Split the shuffled list into committees_per_epoch pieces + return split(shuffled_active_validator_indices, committees_per_epoch) ``` **Invariant**: if `get_shuffling(seed, validators, epoch)` returns some value `x` for some `epoch <= get_current_epoch(state) + ENTRY_EXIT_DELAY`, it should return the same value `x` for the same `seed` and `epoch` and possible future modifications of `validators` forever in phase 0, and until the ~1 year deletion delay in phase 2 and in the future. **Note**: this definition and the next few definitions make heavy use of repetitive computing. Production implementations are expected to appropriately use caching/memoization to avoid redoing work. -#### `get_previous_epoch_committee_count_per_slot` +#### `get_previous_epoch_committee_count` ```python -def get_previous_epoch_committee_count_per_slot(state: BeaconState) -> int: +def get_previous_epoch_committee_count(state: BeaconState) -> int: previous_active_validators = get_active_validator_indices( state.validator_registry, state.previous_calculation_epoch, ) - return get_committee_count_per_slot(len(previous_active_validators)) + return get_epoch_committee_count(len(previous_active_validators)) ``` -#### `get_current_epoch_committee_count_per_slot` +#### `get_current_epoch_committee_count` ```python -def get_current_epoch_committee_count_per_slot(state: BeaconState) -> int: +def get_current_epoch_committee_count(state: BeaconState) -> int: current_active_validators = get_active_validator_indices( state.validator_registry, state.current_calculation_epoch, ) - return get_committee_count_per_slot(len(current_active_validators)) + return get_epoch_committee_count(len(current_active_validators)) ``` #### `get_crosslink_committees_at_slot` @@ -978,12 +978,12 @@ def get_crosslink_committees_at_slot(state: BeaconState, assert previous_epoch <= epoch < next_epoch if epoch < current_epoch: - committees_per_slot = get_previous_epoch_committee_count_per_slot(state) + committees_per_epoch = get_previous_epoch_committee_count(state) seed = state.previous_epoch_seed shuffling_epoch = state.previous_calculation_epoch shuffling_start_shard = state.previous_epoch_start_shard else: - committees_per_slot = get_current_epoch_committee_count_per_slot(state) + committees_per_epoch = get_current_epoch_committee_count(state) seed = state.current_epoch_seed shuffling_epoch = state.current_calculation_epoch shuffling_start_shard = state.current_epoch_start_shard @@ -994,6 +994,7 @@ def get_crosslink_committees_at_slot(state: BeaconState, shuffling_epoch, ) offset = slot % EPOCH_LENGTH + committees_per_slot = committees_per_epoch // EPOCH_LENGTH slot_start_shard = (shuffling_start_shard + committees_per_slot * offset) % SHARD_COUNT return [ @@ -1795,7 +1796,7 @@ First, update the following: If the following are satisfied: * `state.finalized_epoch > state.validator_registry_update_epoch` -* `state.latest_crosslinks[shard].epoch > state.validator_registry_update_epoch` for every shard number `shard` in `[(state.current_epoch_start_shard + i) % SHARD_COUNT for i in range(get_current_epoch_committee_count_per_slot(state) * EPOCH_LENGTH)]` (that is, for every shard in the current committees) +* `state.latest_crosslinks[shard].epoch > state.validator_registry_update_epoch` for every shard number `shard` in `[(state.current_epoch_start_shard + i) % SHARD_COUNT for i in range(get_current_epoch_committee_count(state))]` (that is, for every shard in the current committees) update the validator registry and associated fields by running @@ -1847,7 +1848,7 @@ def update_validator_registry(state: BeaconState) -> None: and perform the following updates: * Set `state.current_calculation_epoch = next_epoch` -* Set `state.current_epoch_start_shard = (state.current_epoch_start_shard + get_current_epoch_committee_count_per_slot(state) * EPOCH_LENGTH) % SHARD_COUNT` +* Set `state.current_epoch_start_shard = (state.current_epoch_start_shard + get_current_epoch_committee_count(state)) % SHARD_COUNT` * Set `state.current_epoch_seed = generate_seed(state, state.current_calculation_epoch)` If a validator registry update does _not_ happen do the following: From 12619995bbe05fde92e1be5f239a9fae583dfe23 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sun, 27 Jan 2019 10:00:03 -0700 Subject: [PATCH 46/70] pr feedback --- specs/core/0_beacon-chain.md | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 2ead71784..44ca758b4 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -810,7 +810,7 @@ def get_current_epoch(state: BeaconState) -> EpochNumber: ```python def get_epoch_start_slot(epoch: EpochNumber) -> SlotNumber: - return slot_to_epoch(state.slot) + return epoch * EPOCH_LENGTH ``` #### `is_active_validator` @@ -920,7 +920,7 @@ def get_shuffling(seed: Bytes32, epoch: EpochNumber) -> List[List[ValidatorIndex]] """ Shuffles ``validators`` into crosslink committees seeded by ``seed`` and ``epoch``. - Returns a list of ``EPOCH_LENGTH * committees_per_slot`` committees where each + Returns a list of ``committees_per_epoch`` committees where each committee is itself a list of validator indices. """ @@ -1053,7 +1053,7 @@ def get_active_index_root(state: BeaconState, ```python def generate_seed(state: BeaconState, - epoch: int) -> Bytes32: + epoch: EpochNumber) -> Bytes32: """ Generate a seed for the given ``epoch``. """ From 8fbaa255963b03236b665d4b5d65379862ec2c6e Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sun, 27 Jan 2019 10:01:04 -0700 Subject: [PATCH 47/70] pr feedback --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 44ca758b4..95289793d 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1239,7 +1239,7 @@ def integer_squareroot(n: int) -> int: #### `get_entry_exit_effect_epoch` ```python -def get_entry_exit_effect_epoch(epoch: int) -> int: +def get_entry_exit_effect_epoch(epoch: EpochNumber) -> EpochNumber: """ An entry or exit triggered in the ``epoch`` given by the input takes effect at the epoch given by the output. From e41eeeedb61e45a154c0559949dc7308e7f93d93 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sun, 27 Jan 2019 10:22:27 -0700 Subject: [PATCH 48/70] make randao_mixes per epoch --- specs/core/0_beacon-chain.md | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 95289793d..068584fa5 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -171,9 +171,9 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `MAX_BALANCE_CHURN_QUOTIENT` | `2**5` (= 32) | - | | `BEACON_CHAIN_SHARD_NUMBER` | `2**64 - 1` | - | | `MAX_CASPER_VOTES` | `2**10` (= 1,024) | votes | -| `LATEST_BLOCK_ROOTS_LENGTH` | `2**13` (= 8,192) | block roots | -| `LATEST_RANDAO_MIXES_LENGTH` | `2**13` (= 8,192) | randao mixes | -| `LATEST_INDEX_ROOTS_LENGTH` | `2**13` (= 8,192) | index roots | +| `LATEST_BLOCK_ROOTS_LENGTH` | `2**13` (= 8,192) | slots | +| `LATEST_RANDAO_MIXES_LENGTH` | `2**13` (= 8,192) | epochs | +| `LATEST_INDEX_ROOTS_LENGTH` | `2**13` (= 8,192) | epochs | | `LATEST_PENALIZED_EXIT_LENGTH` | `2**13` (= 8,192) | epochs | ~36 days | | `MAX_WITHDRAWALS_PER_EPOCH` | `2**2` (= 4) | withdrawals | @@ -1027,13 +1027,13 @@ def get_block_root(state: BeaconState, ```python def get_randao_mix(state: BeaconState, - slot: SlotNumber) -> Bytes32: + epoch: EpochNumber) -> Bytes32: """ Returns the randao mix at a recent ``slot``. """ - assert state.slot < slot + LATEST_RANDAO_MIXES_LENGTH - assert slot <= state.slot - return state.latest_randao_mixes[slot % LATEST_RANDAO_MIXES_LENGTH] + assert get_current_epoch(state) < epoch + LATEST_RANDAO_MIXES_LENGTH + assert epoch <= get_current_epoch(state) + return state.latest_randao_mixes[epoch % LATEST_RANDAO_MIXES_LENGTH] ``` #### `get_active_index_root` @@ -1494,7 +1494,6 @@ Below are the processing steps that happen at every slot. ### Misc counters * Set `state.slot += 1`. -* Set `state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH] = get_randao_mix(state, state.slot - 1)`. ### Block roots @@ -1520,7 +1519,7 @@ Below are the processing steps that happen at every `block`. * Let `proposer = state.validator_registry[get_beacon_proposer_index(state, state.slot)]`. * Verify that `bls_verify(pubkey=proposer.pubkey, message=int_to_bytes32(get_current_epoch(state)), signature=block.randao_reveal, domain=get_domain(state.fork, get_current_epoch(state), DOMAIN_RANDAO))`. -* Set `state.latest_randao_mixes[state.slot % LATEST_RANDAO_MIXES_LENGTH] = xor(get_randao_mix(state, state.slot), hash(block.randao_reveal))`. +* Set `state.latest_randao_mixes[get_current_epoch(state) % LATEST_RANDAO_MIXES_LENGTH] = xor(get_randao_mix(state, get_current_epoch(state)), hash(block.randao_reveal))`. ### Eth1 data @@ -1902,6 +1901,7 @@ def process_penalties_and_exits(state: BeaconState) -> None: ### Final updates * Set `state.latest_penalized_balances[(next_epoch) % LATEST_PENALIZED_EXIT_LENGTH] = state.latest_penalized_balances[current_epoch % LATEST_PENALIZED_EXIT_LENGTH]`. +* Set `state.latest_randao_mixes[next_epoch % LATEST_RANDAO_MIXES_LENGTH] = get_randao_mix(state, current_epoch)`. * Remove any `attestation` in `state.latest_attestations` such that `slot_to_epoch(attestation.data.slot) < current_epoch`. ## State root processing From b0e71f4c80e0d3a82d6c5a62220c6ccbaa002b90 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sun, 27 Jan 2019 10:23:28 -0700 Subject: [PATCH 49/70] pr feedback --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 068584fa5..6659ee3f4 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1689,7 +1689,7 @@ Define the following helpers to process attestation inclusion rewards and inclus ### Eth1 data -If `current_epoch % ETH1_DATA_VOTING_PERIOD == 0`: +If `next_epoch % ETH1_DATA_VOTING_PERIOD == 0`: * Set `state.latest_eth1_data = eth1_data_vote.data` if `eth1_data_vote.vote_count * 2 > ETH1_DATA_VOTING_PERIOD * EPOCH_LENGTH` for some `eth1_data_vote` in `state.eth1_data_votes`. * Set `state.eth1_data_votes = []`. From ad46b9cb1248f2d1023899b4a2fe4fd033e53389 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sun, 27 Jan 2019 10:31:01 -0700 Subject: [PATCH 50/70] pr feedback --- specs/core/0_beacon-chain.md | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 6659ee3f4..35435ed7f 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -774,7 +774,7 @@ def lmd_ghost(store: Store, start_state: BeaconState, start_block: BeaconBlock) We now define the state transition function. At a high level the state transition is made up of two parts: 1. The per-slot transitions, which happens every slot, and only affects a parts of the `state`. -2. The per-epoch transitions, which happens at every epoch boundary (i.e. `state.slot % EPOCH_LENGTH == 0`), and affects the entire `state`. +2. The per-epoch transitions, which happens in the last slot of every epoch (i.e. `(state.slot + 1) % EPOCH_LENGTH == 0`), and affects the entire `state`. The per-slot transitions generally focus on verifying aggregate signatures and saving temporary records relating to the per-slot activity in the `BeaconState`. The per-epoch transitions focus on the [validator](#dfn-validator) registry, including adjusting balances and activating and exiting [validators](#dfn-validator), as well as processing crosslinks and managing block justification/finalization. @@ -1057,13 +1057,10 @@ def generate_seed(state: BeaconState, """ Generate a seed for the given ``epoch``. """ - if epoch < SEED_LOOKAHEAD: - randao_mix_epoch = GENESIS_EPOCH - else: - randao_mix_epoch = epoch - SEED_LOOKAHEAD + randao_mix_epoch = epoch + LATEST_RANDAO_MIXES_LENGTH - SEED_LOOKAHEAD return hash( - get_randao_mix(state, get_epoch_start_slot(randao_mix_epoch)) + + get_randao_mix(state, randao_mix_epoch) + get_active_index_root(state, epoch) ) @@ -1568,7 +1565,7 @@ For each `attestation` in `block.body.attestations`: * Verify that `attestation.data.slot + MIN_ATTESTATION_INCLUSION_DELAY <= state.slot`. * Verify that `attestation.data.slot + EPOCH_LENGTH >= state.slot`. -* Verify that `attestation.data.justified_epoch` is equal to `state.justified_epoch if attestation.data.slot >= state.slot - (state.slot % EPOCH_LENGTH) else state.previous_justified_epoch`. +* Verify that `attestation.data.justified_epoch` is equal to `state.justified_epoch if attestation.data.slot >= get_epoch_start_slot(get_current_epoch(state)) else state.previous_justified_epoch`. * Verify that `attestation.data.justified_block_root` is equal to `get_block_root(state, get_epoch_start_slot(attestation.data.justified_epoch))`. * Verify that either `attestation.data.latest_crosslink_root` or `attestation.data.shard_block_root` equals `state.latest_crosslinks[shard].shard_block_root`. * `aggregate_signature` verification: From 41827d26ecf50d4b02a0e1cb944414a3e399eea6 Mon Sep 17 00:00:00 2001 From: Hsiao-Wei Wang Date: Mon, 28 Jan 2019 01:49:15 +0800 Subject: [PATCH 51/70] Add the brief of `per_block` processing, and nudge some wording --- specs/core/0_beacon-chain.md | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 5a185f63f..fd5cd7d35 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -765,12 +765,13 @@ def lmd_ghost(store: Store, start_state: BeaconState, start_block: BeaconBlock) ## Beacon chain state transition function -We now define the state transition function. At a high level the state transition is made up of two parts: +We now define the state transition function. At a high level the state transition is made up of three parts: -1. The per-slot transitions, which happens every slot, and only affects a parts of the `state`. -2. The per-epoch transitions, which happens at every epoch boundary (i.e. `state.slot % EPOCH_LENGTH == 0`), and affects the entire `state`. +1. The per-slot transitions, which happens every slot. +2. The per-block transitions, which happens at every block. +3. The per-epoch transitions, which happens at every epoch boundary (i.e. `state.slot % EPOCH_LENGTH == 0`). -The per-slot transitions generally focus on verifying aggregate signatures and saving temporary records relating to the per-slot activity in the `BeaconState`. The per-epoch transitions focus on the [validator](#dfn-validator) registry, including adjusting balances and activating and exiting [validators](#dfn-validator), as well as processing crosslinks and managing block justification/finalization. +The per-slot transitions focus on the slot counter and block roots records updates; the per-block transitions generally focus on verifying aggregate signatures and saving temporary records relating to the per-block activity in the `BeaconState`; the per-epoch transitions focus on the [validator](#dfn-validator) registry, including adjusting balances and activating and exiting [validators](#dfn-validator), as well as processing crosslinks and managing block justification/finalization. ### Helper functions From f9b53e858369f6c889f3a99f4850a02b34f51e0f Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sun, 27 Jan 2019 17:20:15 -0700 Subject: [PATCH 52/70] pr feedback --- specs/core/0_beacon-chain.md | 29 +++++++++++++---------------- 1 file changed, 13 insertions(+), 16 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 35435ed7f..21744ecbc 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -96,10 +96,10 @@ - [Routine for processing deposits](#routine-for-processing-deposits) - [Routines for updating validator status](#routines-for-updating-validator-status) - [Per-slot processing](#per-slot-processing) - - [Misc counters](#misc-counters) + - [Slot](#slot) - [Block roots](#block-roots) - [Per-block processing](#per-block-processing) - - [Slot](#slot) + - [Slot](#slot-1) - [Proposer signature](#proposer-signature) - [RANDAO](#randao) - [Eth1 data](#eth1-data) @@ -1488,7 +1488,7 @@ def prepare_validator_for_withdrawal(state: BeaconState, index: ValidatorIndex) Below are the processing steps that happen at every slot. -### Misc counters +### Slot * Set `state.slot += 1`. @@ -1637,13 +1637,9 @@ The steps below happen when `(state.slot + 1) % EPOCH_LENGTH == 0`. * Let `previous_epoch = current_epoch - 1 if current_epoch > GENESIS_EPOCH else current_epoch`. * Let `next_epoch = current_epoch + 1`. -All [validators](#dfn-validator): - -* Let `active_validator_indices = get_active_validator_indices(state.validator_registry, current_epoch)`. -* Let `total_balance = sum([get_effective_balance(state, i) for i in active_validator_indices])`. - [Validators](#dfn-Validator) attesting during the current epoch: +* Let `current_total_balance = sum([get_effective_balance(state, i) for i in get_active_validator_indices(state.validator_registry, current_epoch)])`. * Let `current_epoch_attestations = [a for a in state.latest_attestations if current_epoch == slot_to_epoch(a.data.slot)]`. (Note: this is the set of attestations of slots in the epoch `current_epoch`, _not_ attestations that got included in the chain during the epoch `current_epoch`.) * Validators justifying the epoch boundary block at the start of the current epoch: * Let `current_epoch_boundary_attestations = [a for a in current_epoch_attestations if a.data.epoch_boundary_root == get_block_root(state, get_epoch_start_slot(current_epoch)) and a.data.justified_epoch == state.justified_epoch]`. @@ -1652,6 +1648,7 @@ All [validators](#dfn-validator): [Validators](#dfn-Validator) attesting during the previous epoch: +* Let `previous_total_balance = sum([get_effective_balance(state, i) for i in get_active_validator_indices(state.validator_registry, previous_epoch)])`. * Validators that made an attestation during the previous epoch: * Let `previous_epoch_attestations = [a for a in state.latest_attestations if previous_epoch == slot_to_epoch(a.data.slot)]`. * Let `previous_epoch_attester_indices` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in previous_epoch_attestations]`. @@ -1668,7 +1665,7 @@ All [validators](#dfn-validator): * Let `previous_epoch_head_attester_indices` be the union of the validator index sets given by `[get_attestation_participants(state, a.data, a.aggregation_bitfield) for a in previous_epoch_head_attestations]`. * Let `previous_epoch_head_attesting_balance = sum([get_effective_balance(state, i) for i in previous_epoch_head_attester_indices])`. -**Note**: `previous_epoch_boundary_attesting_balance` balance might be marginally different than `current_epoch_boundary_attesting_balance` during the previous epoch transition. Due to the tight bound on validator churn each epoch and small per-epoch rewards/penalties, the potential balance difference is very low and only marginally affects consensus safety. +**Note**: `previous_total_balance` and `previous_epoch_boundary_attesting_balance` balance might be marginally different than the actual balances during previous epoch transition. Due to the tight bound on validator churn each epoch and small per-epoch rewards/penalties, the potential balance difference is very low and only marginally affects consensus safety. For every `slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_slot(next_epoch))`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: @@ -1696,9 +1693,9 @@ If `next_epoch % ETH1_DATA_VOTING_PERIOD == 0`: First, update the justification bitfield: * Let `new_justified_epoch = state.justified_epoch`. -* Set `state.justification_bitfield = (state.justification_bitfield * 2) % 2**64`. -* Set `state.justification_bitfield |= 2` and `new_justified_epoch = previous_epoch` if `3 * previous_epoch_boundary_attesting_balance >= 2 * total_balance`. -* Set `state.justification_bitfield |= 1` and `new_justified_epoch = current_epoch` if `3 * current_epoch_boundary_attesting_balance >= 2 * total_balance`. +* Set `state.justification_bitfield = state.justification_bitfield << 1`. +* Set `state.justification_bitfield |= 2` and `new_justified_epoch = previous_epoch` if `3 * previous_epoch_boundary_attesting_balance >= 2 * previous_total_balance`. +* Set `state.justification_bitfield |= 1` and `new_justified_epoch = current_epoch` if `3 * current_epoch_boundary_attesting_balance >= 2 * current_total_balance`. Next, update last finalized epoch if possible: @@ -1722,7 +1719,7 @@ For every `slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_s First, we define some additional helpers: -* Let `base_reward_quotient = integer_squareroot(total_balance) // BASE_REWARD_QUOTIENT`. +* Let `base_reward_quotient = integer_squareroot(previous_total_balance) // BASE_REWARD_QUOTIENT`. * Let `base_reward(state, index) = get_effective_balance(state, index) // base_reward_quotient // 5` for any validator with the given `index`. * Let `inactivity_penalty(state, index, epochs_since_finality) = base_reward(state, index) + get_effective_balance(state, index) * epochs_since_finality // INACTIVITY_PENALTY_QUOTIENT // 2` for any validator with the given `index`. @@ -1735,13 +1732,13 @@ Note: When applying penalties in the following balance recalculations implemente Case 1: `epochs_since_finality <= 4`: * Expected FFG source: - * Any [validator](#dfn-validator) `index` in `previous_epoch_justified_attester_indices` gains `base_reward(state, index) * previous_epoch_justified_attesting_balance // total_balance`. + * Any [validator](#dfn-validator) `index` in `previous_epoch_justified_attester_indices` gains `base_reward(state, index) * previous_epoch_justified_attesting_balance // previous_total_balance`. * Any [active validator](#dfn-active-validator) `v` not in `previous_epoch_justified_attester_indices` loses `base_reward(state, index)`. * Expected FFG target: - * Any [validator](#dfn-validator) `index` in `previous_epoch_boundary_attester_indices` gains `base_reward(state, index) * previous_epoch_boundary_attesting_balance // total_balance`. + * Any [validator](#dfn-validator) `index` in `previous_epoch_boundary_attester_indices` gains `base_reward(state, index) * previous_epoch_boundary_attesting_balance // previous_total_balance`. * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_boundary_attester_indices` loses `base_reward(state, index)`. * Expected beacon chain head: - * Any [validator](#dfn-validator) `index` in `previous_epoch_head_attester_indices` gains `base_reward(state, index) * previous_epoch_head_attesting_balance // total_balance)`. + * Any [validator](#dfn-validator) `index` in `previous_epoch_head_attester_indices` gains `base_reward(state, index) * previous_epoch_head_attesting_balance // previous_total_balance)`. * Any [active validator](#dfn-active-validator) `index` not in `previous_epoch_head_attester_indices` loses `base_reward(state, index)`. * Inclusion distance: * Any [validator](#dfn-validator) `index` in `previous_epoch_attester_indices` gains `base_reward(state, index) * MIN_ATTESTATION_INCLUSION_DELAY // inclusion_distance(state, index)` From 1947fc0ff32b522f1c0d8bff9159a9f90848bc71 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sun, 27 Jan 2019 17:25:29 -0700 Subject: [PATCH 53/70] pr feedback --- specs/core/0_beacon-chain.md | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 21744ecbc..10a41506f 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -15,6 +15,7 @@ - [Deposit contract](#deposit-contract) - [Initial values](#initial-values) - [Time parameters](#time-parameters) + - [State list lengths](#state-list-lengths) - [Reward and penalty quotients](#reward-and-penalty-quotients) - [Status flags](#status-flags) - [Max operations per block](#max-operations-per-block) @@ -171,10 +172,6 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `MAX_BALANCE_CHURN_QUOTIENT` | `2**5` (= 32) | - | | `BEACON_CHAIN_SHARD_NUMBER` | `2**64 - 1` | - | | `MAX_CASPER_VOTES` | `2**10` (= 1,024) | votes | -| `LATEST_BLOCK_ROOTS_LENGTH` | `2**13` (= 8,192) | slots | -| `LATEST_RANDAO_MIXES_LENGTH` | `2**13` (= 8,192) | epochs | -| `LATEST_INDEX_ROOTS_LENGTH` | `2**13` (= 8,192) | epochs | -| `LATEST_PENALIZED_EXIT_LENGTH` | `2**13` (= 8,192) | epochs | ~36 days | | `MAX_WITHDRAWALS_PER_EPOCH` | `2**2` (= 4) | withdrawals | * For the safety of crosslinks `TARGET_COMMITTEE_SIZE` exceeds [the recommended minimum committee size of 111](https://vitalik.ca/files/Ithaca201807_Sharding.pdf); with sufficient active validators (at least `EPOCH_LENGTH * TARGET_COMMITTEE_SIZE`), the shuffling algorithm ensures committee sizes at least `TARGET_COMMITTEE_SIZE`. (Unbiasable randomness with a Verifiable Delay Function (VDF) will improve committee robustness and lower the safe minimum committee size.) @@ -213,6 +210,14 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `ETH1_DATA_VOTING_PERIOD` | `2**4` (= 16) | epochs | ~1.7 hours | | `MIN_VALIDATOR_WITHDRAWAL_EPOCHS` | `2**8` (= 256) | epochs | ~27 hours | +### State list lengths + +| Name | Value | Unit | +| `LATEST_BLOCK_ROOTS_LENGTH` | `2**13` (= 8,192) | slots | +| `LATEST_RANDAO_MIXES_LENGTH` | `2**13` (= 8,192) | epochs | +| `LATEST_INDEX_ROOTS_LENGTH` | `2**13` (= 8,192) | epochs | +| `LATEST_PENALIZED_EXIT_LENGTH` | `2**13` (= 8,192) | epochs | + ### Reward and penalty quotients | Name | Value | @@ -1757,10 +1762,12 @@ For each `index` in `previous_epoch_attester_indices`, we determine the proposer #### Crosslinks -For every `slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_slot(current_epoch))`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: +For every `slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_slot(current_epoch))`: -* If `index in attesting_validators(crosslink_committee)`, `state.validator_balances[index] += base_reward(state, index) * total_attesting_balance(crosslink_committee) // total_balance(crosslink_committee))`. -* If `index not in attesting_validators(crosslink_committee)`, `state.validator_balances[index] -= base_reward(state, index)`. +* Let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. +* For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`: + * If `index in attesting_validators(crosslink_committee)`, `state.validator_balances[index] += base_reward(state, index) * total_attesting_balance(crosslink_committee) // total_balance(crosslink_committee))`. + * If `index not in attesting_validators(crosslink_committee)`, `state.validator_balances[index] -= base_reward(state, index)`. ### Ejections From 7b9c033578eeca3d2e55275c681d25ab7dd44d51 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sun, 27 Jan 2019 20:40:30 -0700 Subject: [PATCH 54/70] remove extra line --- specs/core/0_beacon-chain.md | 1 - 1 file changed, 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 10a41506f..3ce31da06 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1068,7 +1068,6 @@ def generate_seed(state: BeaconState, get_randao_mix(state, randao_mix_epoch) + get_active_index_root(state, epoch) ) - ``` #### `get_beacon_proposer_index` From c9a2f9258e792c24bdc02d39038984b14367a1c8 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Sun, 27 Jan 2019 21:29:47 -0700 Subject: [PATCH 55/70] pr feedback --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 3ce31da06..4d021bc3d 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1689,7 +1689,7 @@ Define the following helpers to process attestation inclusion rewards and inclus If `next_epoch % ETH1_DATA_VOTING_PERIOD == 0`: -* Set `state.latest_eth1_data = eth1_data_vote.data` if `eth1_data_vote.vote_count * 2 > ETH1_DATA_VOTING_PERIOD * EPOCH_LENGTH` for some `eth1_data_vote` in `state.eth1_data_votes`. +* If `eth1_data_vote.vote_count * 2 > ETH1_DATA_VOTING_PERIOD * EPOCH_LENGTH` for some `eth1_data_vote` in `state.eth1_data_votes` (ie. more than half the votes in this voting period were for that value), set `state.latest_eth1_data = eth1_data_vote.data`. * Set `state.eth1_data_votes = []`. ### Justification From 656eae6f6ad85de5f4b9493ca0a4f8ca16d2e261 Mon Sep 17 00:00:00 2001 From: vbuterin Date: Sun, 27 Jan 2019 23:12:37 -0600 Subject: [PATCH 56/70] Minimum slot number, simplify excessive anti-underflow logic Adds a minimum slot number large enough that integer underflows involving epochs and slots will not happen; simplifies some logic that was more complex to handle them. --- specs/core/0_beacon-chain.md | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 4d021bc3d..6e07c3857 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -190,7 +190,7 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | Name | Value | | - | - | | `GENESIS_FORK_VERSION` | `0` | -| `GENESIS_SLOT` | `0` | +| `GENESIS_SLOT` | `2**19` | | `GENESIS_EPOCH` | `slot_to_epoch(GENESIS_SLOT)` | | `GENESIS_START_SHARD` | `0` | | `FAR_FUTURE_EPOCH` | `2**64 - 1` | @@ -198,6 +198,8 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `EMPTY_SIGNATURE` | `int_to_bytes96(0)` | | `BLS_WITHDRAWAL_PREFIX_BYTE` | `int_to_bytes1(0)` | +* `GENESIS_SLOT` should be at least as large in terms of time as the largest of the time parameters or state list lengths below (ie. it should be at least as large as any value measured in slots, and at least `EPOCH_LENGTH` times as large as any value measured in epochs). + ### Time parameters | Name | Value | Unit | Duration | @@ -212,11 +214,12 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be ### State list lengths -| Name | Value | Unit | -| `LATEST_BLOCK_ROOTS_LENGTH` | `2**13` (= 8,192) | slots | -| `LATEST_RANDAO_MIXES_LENGTH` | `2**13` (= 8,192) | epochs | -| `LATEST_INDEX_ROOTS_LENGTH` | `2**13` (= 8,192) | epochs | -| `LATEST_PENALIZED_EXIT_LENGTH` | `2**13` (= 8,192) | epochs | +| Name | Value | Unit | Duration | +| - | - | :-: | :-: | +| `LATEST_BLOCK_ROOTS_LENGTH` | `2**13` (= 8,192) | slots | ~13 hours | +| `LATEST_RANDAO_MIXES_LENGTH` | `2**13` (= 8,192) | epochs | ~36 days | +| `LATEST_INDEX_ROOTS_LENGTH` | `2**13` (= 8,192) | epochs | ~36 days | +| `LATEST_PENALIZED_EXIT_LENGTH` | `2**13` (= 8,192) | epochs | ~36 days | ### Reward and penalty quotients @@ -1036,8 +1039,7 @@ def get_randao_mix(state: BeaconState, """ Returns the randao mix at a recent ``slot``. """ - assert get_current_epoch(state) < epoch + LATEST_RANDAO_MIXES_LENGTH - assert epoch <= get_current_epoch(state) + assert get_current_epoch(state) - LATEST_RANDAO_MIXES_LENGTH < epoch <= get_current_epoch(state) return state.latest_randao_mixes[epoch % LATEST_RANDAO_MIXES_LENGTH] ``` @@ -1049,8 +1051,7 @@ def get_active_index_root(state: BeaconState, """ Returns the index root at a recent ``epoch``. """ - assert get_current_epoch(state) < epoch + LATEST_INDEX_ROOTS_LENGTH - assert epoch <= get_current_epoch(state) + assert get_current_epoch(state) - LATEST_INDEX_ROOTS_LENGTH < epoch <= get_current_epoch(state) return state.latest_index_roots[epoch % LATEST_INDEX_ROOTS_LENGTH] ``` @@ -1062,10 +1063,9 @@ def generate_seed(state: BeaconState, """ Generate a seed for the given ``epoch``. """ - randao_mix_epoch = epoch + LATEST_RANDAO_MIXES_LENGTH - SEED_LOOKAHEAD return hash( - get_randao_mix(state, randao_mix_epoch) + + get_randao_mix(state, epoch - SEED_LOOKAHEAD) + get_active_index_root(state, epoch) ) ``` From ca3d0b8b534b19646fa9936dc8a25c6686c9972e Mon Sep 17 00:00:00 2001 From: vbuterin Date: Sun, 27 Jan 2019 23:36:38 -0600 Subject: [PATCH 57/70] slot -> epoch --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 6e07c3857..2606389e2 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1037,7 +1037,7 @@ def get_block_root(state: BeaconState, def get_randao_mix(state: BeaconState, epoch: EpochNumber) -> Bytes32: """ - Returns the randao mix at a recent ``slot``. + Returns the randao mix at a recent ``epoch``. """ assert get_current_epoch(state) - LATEST_RANDAO_MIXES_LENGTH < epoch <= get_current_epoch(state) return state.latest_randao_mixes[epoch % LATEST_RANDAO_MIXES_LENGTH] From ce73a8327f40fcec81f7582bfed43815c1b417fd Mon Sep 17 00:00:00 2001 From: Hsiao-Wei Wang Date: Mon, 28 Jan 2019 08:26:48 -0700 Subject: [PATCH 58/70] Update specs/core/0_beacon-chain.md Co-Authored-By: djrtwo --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 2606389e2..a2634c11a 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -980,7 +980,7 @@ def get_crosslink_committees_at_slot(state: BeaconState, """ epoch = slot_to_epoch(slot) current_epoch = get_current_epoch(state) - previous_epoch = current_epoch - 1 if epoch > GENESIS_EPOCH else current_epoch + previous_epoch = current_epoch - 1 if current_epoch > GENESIS_EPOCH else current_epoch next_epoch = current_epoch + 1 assert previous_epoch <= epoch < next_epoch From 7b7cf7cf758b5c09640052fccb37f07b1aecb0f8 Mon Sep 17 00:00:00 2001 From: vbuterin Date: Mon, 28 Jan 2019 12:01:51 -0600 Subject: [PATCH 59/70] Add link to honest validator implementation doc to main readme --- README.md | 1 + 1 file changed, 1 insertion(+) diff --git a/README.md b/README.md index f3aba3f64..c5c88daf9 100644 --- a/README.md +++ b/README.md @@ -16,6 +16,7 @@ Accompanying documents can be found in [specs](specs) and include * [SimpleSerialize (SSZ) spec](specs/simple-serialize.md) * [BLS signature verification](specs/bls_signature.md) * [General test format](specs/test-format.md) +* [Honest validator implementation doc](specs/validator/0_beacon-chain-validator.md) ## Design goals The following are the broad design goals for Ethereum 2.0: From a14600e3a47fddf60910b7693d1b5cc635602dd2 Mon Sep 17 00:00:00 2001 From: vbuterin Date: Mon, 28 Jan 2019 12:24:09 -0600 Subject: [PATCH 60/70] Edits * Removed comment beside `latest_block_roots` "Needed to process attestations, older to newer" because it is no longer accurate * Clarified per-slot processing * Casper slashing -> attester slashing --- specs/core/0_beacon-chain.md | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 50351106d..c0e247108 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -24,8 +24,8 @@ - [Beacon chain operations](#beacon-chain-operations) - [Proposer slashings](#proposer-slashings) - [`ProposerSlashing`](#proposerslashing) - - [Casper slashings](#casper-slashings) - - [`CasperSlashing`](#casperslashing) + - [Attester slashings](#attester-slashings) + - [`AttesterSlashing`](#attesterslashing) - [`SlashableVoteData`](#slashablevotedata) - [Attestations](#attestations) - [`Attestation`](#attestation) @@ -106,7 +106,7 @@ - [Eth1 data](#eth1-data) - [Operations](#operations) - [Proposer slashings](#proposer-slashings-1) - - [Casper slashings](#casper-slashings-1) + - [Attester slashings](#attester-slashings-1) - [Attestations](#attestations-1) - [Deposits](#deposits-1) - [Exits](#exits-1) @@ -245,7 +245,7 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | Name | Value | | - | - | | `MAX_PROPOSER_SLASHINGS` | `2**4` (= 16) | -| `MAX_CASPER_SLASHINGS` | `2**4` (= 16) | +| `MAX_ATTESTER_SLASHINGS` | `2**4` (= 16) | | `MAX_ATTESTATIONS` | `2**7` (= 128) | | `MAX_DEPOSITS` | `2**4` (= 16) | | `MAX_EXITS` | `2**4` (= 16) | @@ -285,9 +285,9 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git } ``` -#### Casper slashings +#### Attester slashings -##### `CasperSlashing` +##### `AttesterSlashing` ```python { @@ -444,7 +444,7 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git ```python { 'proposer_slashings': [ProposerSlashing], - 'casper_slashings': [CasperSlashing], + 'attester_slashings': [AttesterSlashing], 'attestations': [Attestation], 'custody_reseeds': [CustodyReseed], 'custody_challenges': [CustodyChallenge], @@ -507,7 +507,7 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git # Recent state 'latest_crosslinks': [Crosslink], - 'latest_block_roots': ['bytes32'], # Needed to process attestations, older to newer + 'latest_block_roots': ['bytes32'], 'latest_index_roots': ['bytes32'], 'latest_penalized_balances': ['uint64'], # Balances penalized at every withdrawal period 'latest_attestations': [PendingAttestation], @@ -1278,7 +1278,7 @@ A valid block with slot `GENESIS_SLOT` (a "genesis block") has the following val signature=EMPTY_SIGNATURE, body=BeaconBlockBody( proposer_slashings=[], - casper_slashings=[], + attester_slashings=[], attestations=[], custody_reseeds=[], custody_challenges=[], @@ -1491,7 +1491,7 @@ def prepare_validator_for_withdrawal(state: BeaconState, index: ValidatorIndex) ## Per-slot processing -Below are the processing steps that happen at every slot. +Below are the processing steps that happen at every slot. If there are skipped slots between a block and its parent block, run the steps in this section once for each skipped slot and then once for the slot containing the new block. ### Slot @@ -1545,14 +1545,14 @@ For each `proposer_slashing` in `block.body.proposer_slashings`: * Verify that `bls_verify(pubkey=proposer.pubkey, message=hash_tree_root(proposer_slashing.proposal_data_2), signature=proposer_slashing.proposal_signature_2, domain=get_domain(state.fork, slot_to_epoch(proposer_slashing.proposal_data_2.slot), DOMAIN_PROPOSAL))`. * Run `penalize_validator(state, proposer_slashing.proposer_index)`. -#### Casper slashings +#### Attester slashings -Verify that `len(block.body.casper_slashings) <= MAX_CASPER_SLASHINGS`. +Verify that `len(block.body.attester_slashings) <= MAX_ATTESTER_SLASHINGS`. -For each `casper_slashing` in `block.body.casper_slashings`: +For each `attester_slashing` in `block.body.attester_slashings`: -* Let `slashable_vote_data_1 = casper_slashing.slashable_vote_data_1`. -* Let `slashable_vote_data_2 = casper_slashing.slashable_vote_data_2`. +* Let `slashable_vote_data_1 = attester_slashing.slashable_vote_data_1`. +* Let `slashable_vote_data_2 = attester_slashing.slashable_vote_data_2`. * Let `indices(slashable_vote_data) = slashable_vote_data.custody_bit_0_indices + slashable_vote_data.custody_bit_1_indices`. * Let `intersection = [x for x in indices(slashable_vote_data_1) if x in indices(slashable_vote_data_2)]`. * Verify that `len(intersection) >= 1`. From 9b7d94f07babca4bbd1359e4b9276759af0704d0 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Mon, 28 Jan 2019 18:31:13 +0000 Subject: [PATCH 61/70] Apply suggestions from code review Co-Authored-By: JustinDrake --- specs/core/0_beacon-chain.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 6a04eb2fb..bb5a0b850 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -361,7 +361,7 @@ The following data structures are defined as [SimpleSerialize (SSZ)](https://git # Attestation data 'data': AttestationData, # Custody bit - 'custody_bit': bool, + 'custody_bit': 'bool', } ``` @@ -1624,7 +1624,7 @@ For each `attestation` in `block.body.attestations`: hash_tree_root(AttestationDataAndCustodyBit(data=attestation.data, custody_bit=0b1)), ], signature=attestation.aggregate_signature, - domain=get_domain(state.fork, attestation.data.slot, DOMAIN_ATTESTATION), + domain=get_domain(state.fork, slot_to_epoch(attestation.data.slot), DOMAIN_ATTESTATION), ) ``` From 053b8ec2a54e65471d8a8801c8ee25fd64341af6 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Mon, 28 Jan 2019 12:15:43 -0700 Subject: [PATCH 62/70] cleanup state transition organization and notes --- specs/core/0_beacon-chain.md | 1528 +++++++++++++++++----------------- 1 file changed, 773 insertions(+), 755 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index c0e247108..f57ad9a6f 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -50,80 +50,86 @@ - [`Eth1Data`](#eth1data) - [`Eth1DataVote`](#eth1datavote) - [Custom Types](#custom-types) + - [Helper functions](#helper-functions) + - [`hash`](#hash) + - [`hash_tree_root`](#hash_tree_root) + - [`slot_to_epoch`](#slot_to_epoch) + - [`get_current_epoch`](#get_current_epoch) + - [`get_epoch_start_slot`](#get_epoch_start_slot) + - [`is_active_validator`](#is_active_validator) + - [`get_active_validator_indices`](#get_active_validator_indices) + - [`shuffle`](#shuffle) + - [`split`](#split) + - [`get_epoch_committee_count`](#get_epoch_committee_count) + - [`get_shuffling`](#get_shuffling) + - [`get_previous_epoch_committee_count`](#get_previous_epoch_committee_count) + - [`get_current_epoch_committee_count`](#get_current_epoch_committee_count) + - [`get_crosslink_committees_at_slot`](#get_crosslink_committees_at_slot) + - [`get_block_root`](#get_block_root) + - [`get_randao_mix`](#get_randao_mix) + - [`get_active_index_root`](#get_active_index_root) + - [`generate_seed`](#generate_seed) + - [`get_beacon_proposer_index`](#get_beacon_proposer_index) + - [`merkle_root`](#merkle_root) + - [`get_attestation_participants`](#get_attestation_participants) + - [`int_to_bytes1`, `int_to_bytes2`, ...](#int_to_bytes1-int_to_bytes2-) + - [`get_effective_balance`](#get_effective_balance) + - [`get_fork_version`](#get_fork_version) + - [`get_domain`](#get_domain) + - [`verify_slashable_vote_data`](#verify_slashable_vote_data) + - [`is_double_vote`](#is_double_vote) + - [`is_surround_vote`](#is_surround_vote) + - [`integer_squareroot`](#integer_squareroot) + - [`get_entry_exit_effect_epoch`](#get_entry_exit_effect_epoch) + - [`bls_verify`](#bls_verify) + - [`bls_verify_multiple`](#bls_verify_multiple) + - [`bls_aggregate_pubkeys`](#bls_aggregate_pubkeys) + - [`validate_proof_of_possession`](#validate_proof_of_possession) + - [`process_deposit`](#process_deposit) + - [`Routines for updating validator status`](#routines-for-updating-validator-status) + - [`activate_validator`](#activate_validator) + - [`initiate_validator_exit`](#initiate_validator_exit) + - [`exit_validator`](#exit_validator) + - [`penalize_validator`](#penalize_validator) + - [`prepare_validator_for_withdrawal`](#prepare_validator_for_withdrawal) - [Ethereum 1.0 deposit contract](#ethereum-10-deposit-contract) - [Deposit arguments](#deposit-arguments) - [Withdrawal credentials](#withdrawal-credentials) - [`Deposit` logs](#deposit-logs) - [`ChainStart` log](#chainstart-log) - [Vyper code](#vyper-code) + - [On startup](#on-startup) - [Beacon chain processing](#beacon-chain-processing) - [Beacon chain fork choice rule](#beacon-chain-fork-choice-rule) - [Beacon chain state transition function](#beacon-chain-state-transition-function) - - [Helper functions](#helper-functions) - - [`hash`](#hash) - - [`hash_tree_root`](#hash_tree_root) - - [`slot_to_epoch`](#slot_to_epoch) - - [`get_current_epoch`](#get_current_epoch) - - [`get_epoch_start_slot`](#get_epoch_start_slot) - - [`is_active_validator`](#is_active_validator) - - [`get_active_validator_indices`](#get_active_validator_indices) - - [`shuffle`](#shuffle) - - [`split`](#split) - - [`get_epoch_committee_count`](#get_epoch_committee_count) - - [`get_shuffling`](#get_shuffling) - - [`get_previous_epoch_committee_count`](#get_previous_epoch_committee_count) - - [`get_current_epoch_committee_count`](#get_current_epoch_committee_count) - - [`get_crosslink_committees_at_slot`](#get_crosslink_committees_at_slot) - - [`get_block_root`](#get_block_root) - - [`get_randao_mix`](#get_randao_mix) - - [`get_active_index_root`](#get_active_index_root) - - [`generate_seed`](#generate_seed) - - [`get_beacon_proposer_index`](#get_beacon_proposer_index) - - [`merkle_root`](#merkle_root) - - [`get_attestation_participants`](#get_attestation_participants) - - [`int_to_bytes1`, `int_to_bytes2`, ...](#int_to_bytes1-int_to_bytes2-) - - [`get_effective_balance`](#get_effective_balance) - - [`get_fork_version`](#get_fork_version) - - [`get_domain`](#get_domain) - - [`verify_slashable_vote_data`](#verify_slashable_vote_data) - - [`is_double_vote`](#is_double_vote) - - [`is_surround_vote`](#is_surround_vote) - - [`integer_squareroot`](#integer_squareroot) - - [`get_entry_exit_effect_epoch`](#get_entry_exit_effect_epoch) - - [`bls_verify`](#bls_verify) - - [`bls_verify_multiple`](#bls_verify_multiple) - - [`bls_aggregate_pubkeys`](#bls_aggregate_pubkeys) - - [On startup](#on-startup) - - [Routine for processing deposits](#routine-for-processing-deposits) - - [Routines for updating validator status](#routines-for-updating-validator-status) - - [Per-slot processing](#per-slot-processing) - - [Slot](#slot) - - [Block roots](#block-roots) - - [Per-block processing](#per-block-processing) - - [Slot](#slot-1) - - [Proposer signature](#proposer-signature) - - [RANDAO](#randao) - - [Eth1 data](#eth1-data) - - [Operations](#operations) - - [Proposer slashings](#proposer-slashings-1) - - [Attester slashings](#attester-slashings-1) - - [Attestations](#attestations-1) - - [Deposits](#deposits-1) - - [Exits](#exits-1) - - [Custody](#custody) - - [Per-epoch processing](#per-epoch-processing) - - [Helpers](#helpers) - - [Eth1 data](#eth1-data-1) - - [Justification](#justification) - - [Crosslinks](#crosslinks) - - [Rewards and penalties](#rewards-and-penalties) - - [Justification and finalization](#justification-and-finalization) - - [Attestation inclusion](#attestation-inclusion) - - [Crosslinks](#crosslinks-1) - - [Ejections](#ejections) - - [Validator registry and shuffling seed data](#validator-registry-and-shuffling-seed-data) - - [Final updates](#final-updates) - - [State root processing](#state-root-processing) + - [Per-slot processing](#per-slot-processing) + - [Slot](#slot) + - [Block roots](#block-roots) + - [Per-block processing](#per-block-processing) + - [Slot](#slot-1) + - [Proposer signature](#proposer-signature) + - [RANDAO](#randao) + - [Eth1 data](#eth1-data) + - [Operations](#operations) + - [Proposer slashings](#proposer-slashings-1) + - [Attester slashings](#attester-slashings-1) + - [Attestations](#attestations-1) + - [Deposits](#deposits-1) + - [Exits](#exits-1) + - [Custody](#custody) + - [Per-epoch processing](#per-epoch-processing) + - [Helpers](#helpers) + - [Eth1 data](#eth1-data-1) + - [Justification](#justification) + - [Crosslinks](#crosslinks) + - [Rewards and penalties](#rewards-and-penalties) + - [Justification and finalization](#justification-and-finalization) + - [Attestation inclusion](#attestation-inclusion) + - [Crosslinks](#crosslinks-1) + - [Ejections](#ejections) + - [Validator registry and shuffling seed data](#validator-registry-and-shuffling-seed-data) + - [Final updates](#final-updates) + - [State root verification](#state-root-verification) - [References](#references) - [Normative](#normative) - [Informative](#informative) @@ -622,6 +628,616 @@ We define the following Python custom types for type hinting and readability: | `BLSPubkey` | 48-byte data | a public key in BLS signature scheme | | `BLSSignature` | 96-byte data | a signature in BLS signature scheme | +## Helper functions + +Note: The definitions below are for specification purposes and are not necessarily optimal implementations. + +### `hash` + +The hash function is denoted by `hash`. In Phase 0 the beacon chain is deployed with the same hash function as Ethereum 1.0, i.e. Keccak-256 (also incorrectly known as SHA3). + +Note: We aim to migrate to a S[T/N]ARK-friendly hash function in a future Ethereum 2.0 deployment phase. + +### `hash_tree_root` + +`def hash_tree_root(object: SSZSerializable) -> Bytes32` is a function for hashing objects into a single root utilizing a hash tree structure. `hash_tree_root` is defined in the [SimpleSerialize spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/simple-serialize.md#tree-hash). + +### `slot_to_epoch` + +```python +def slot_to_epoch(slot: SlotNumber) -> EpochNumber: + return slot // EPOCH_LENGTH +``` + +### `get_current_epoch` + +```python +def get_current_epoch(state: BeaconState) -> EpochNumber: + return slot_to_epoch(state.slot) +``` + +### `get_epoch_start_slot` + +```python +def get_epoch_start_slot(epoch: EpochNumber) -> SlotNumber: + return epoch * EPOCH_LENGTH +``` + +### `is_active_validator` +```python +def is_active_validator(validator: Validator, epoch: EpochNumber) -> bool: + """ + Checks if ``validator`` is active. + """ + return validator.activation_epoch <= epoch < validator.exit_epoch +``` + +### `get_active_validator_indices` + +```python +def get_active_validator_indices(validators: List[Validator], epoch: EpochNumber) -> List[ValidatorIndex]: + """ + Gets indices of active validators from ``validators``. + """ + return [i for i, v in enumerate(validators) if is_active_validator(v, epoch)] +``` + +### `shuffle` + +```python +def shuffle(values: List[Any], seed: Bytes32) -> List[Any]: + """ + Returns the shuffled ``values`` with ``seed`` as entropy. + """ + values_count = len(values) + + # Entropy is consumed from the seed in 3-byte (24 bit) chunks. + rand_bytes = 3 + # The highest possible result of the RNG. + rand_max = 2 ** (rand_bytes * 8) - 1 + + # The range of the RNG places an upper-bound on the size of the list that + # may be shuffled. It is a logic error to supply an oversized list. + assert values_count < rand_max + + output = [x for x in values] + source = seed + index = 0 + while index < values_count - 1: + # Re-hash the `source` to obtain a new pattern of bytes. + source = hash(source) + # Iterate through the `source` bytes in 3-byte chunks. + for position in range(0, 32 - (32 % rand_bytes), rand_bytes): + # Determine the number of indices remaining in `values` and exit + # once the last index is reached. + remaining = values_count - index + if remaining == 1: + break + + # Read 3-bytes of `source` as a 24-bit big-endian integer. + sample_from_source = int.from_bytes(source[position:position + rand_bytes], 'big') + + # Sample values greater than or equal to `sample_max` will cause + # modulo bias when mapped into the `remaining` range. + sample_max = rand_max - rand_max % remaining + + # Perform a swap if the consumed entropy will not cause modulo bias. + if sample_from_source < sample_max: + # Select a replacement index for the current index. + replacement_position = (sample_from_source % remaining) + index + # Swap the current index with the replacement index. + output[index], output[replacement_position] = output[replacement_position], output[index] + index += 1 + else: + # The sample causes modulo bias. A new sample should be read. + pass + + return output +``` + +### `split` + +```python +def split(values: List[Any], split_count: int) -> List[List[Any]]: + """ + Splits ``values`` into ``split_count`` pieces. + """ + list_length = len(values) + return [ + values[(list_length * i // split_count): (list_length * (i + 1) // split_count)] + for i in range(split_count) + ] +``` + +### `get_epoch_committee_count` + +```python +def get_epoch_committee_count(active_validator_count: int) -> int: + return max( + 1, + min( + SHARD_COUNT // EPOCH_LENGTH, + active_validator_count // EPOCH_LENGTH // TARGET_COMMITTEE_SIZE, + ) + ) * EPOCH_LENGTH +``` + +### `get_shuffling` + +```python +def get_shuffling(seed: Bytes32, + validators: List[Validator], + epoch: EpochNumber) -> List[List[ValidatorIndex]] + """ + Shuffles ``validators`` into crosslink committees seeded by ``seed`` and ``epoch``. + Returns a list of ``committees_per_epoch`` committees where each + committee is itself a list of validator indices. + """ + + active_validator_indices = get_active_validator_indices(validators, epoch) + + committees_per_epoch = get_epoch_committee_count(len(active_validator_indices)) + + # Shuffle + seed = xor(seed, int_to_bytes32(epoch)) + shuffled_active_validator_indices = shuffle(active_validator_indices, seed) + + # Split the shuffled list into committees_per_epoch pieces + return split(shuffled_active_validator_indices, committees_per_epoch) +``` + +**Invariant**: if `get_shuffling(seed, validators, epoch)` returns some value `x` for some `epoch <= get_current_epoch(state) + ENTRY_EXIT_DELAY`, it should return the same value `x` for the same `seed` and `epoch` and possible future modifications of `validators` forever in phase 0, and until the ~1 year deletion delay in phase 2 and in the future. + +**Note**: this definition and the next few definitions make heavy use of repetitive computing. Production implementations are expected to appropriately use caching/memoization to avoid redoing work. + +#### `get_previous_epoch_committee_count` + +```python +def get_previous_epoch_committee_count(state: BeaconState) -> int: + previous_active_validators = get_active_validator_indices( + state.validator_registry, + state.previous_calculation_epoch, + ) + return get_epoch_committee_count(len(previous_active_validators)) +``` + +### `get_current_epoch_committee_count` + +```python +def get_current_epoch_committee_count(state: BeaconState) -> int: + current_active_validators = get_active_validator_indices( + state.validator_registry, + state.current_calculation_epoch, + ) + return get_epoch_committee_count(len(current_active_validators)) +``` + +### `get_crosslink_committees_at_slot` + +```python +def get_crosslink_committees_at_slot(state: BeaconState, + slot: SlotNumber) -> List[Tuple[List[ValidatorIndex], ShardNumber]]: + """ + Returns the list of ``(committee, shard)`` tuples for the ``slot``. + """ + epoch = slot_to_epoch(slot) + current_epoch = get_current_epoch(state) + previous_epoch = current_epoch - 1 if current_epoch > GENESIS_EPOCH else current_epoch + next_epoch = current_epoch + 1 + + assert previous_epoch <= epoch < next_epoch + + if epoch < current_epoch: + committees_per_epoch = get_previous_epoch_committee_count(state) + seed = state.previous_epoch_seed + shuffling_epoch = state.previous_calculation_epoch + shuffling_start_shard = state.previous_epoch_start_shard + else: + committees_per_epoch = get_current_epoch_committee_count(state) + seed = state.current_epoch_seed + shuffling_epoch = state.current_calculation_epoch + shuffling_start_shard = state.current_epoch_start_shard + + shuffling = get_shuffling( + seed, + state.validator_registry, + shuffling_epoch, + ) + offset = slot % EPOCH_LENGTH + committees_per_slot = committees_per_epoch // EPOCH_LENGTH + slot_start_shard = (shuffling_start_shard + committees_per_slot * offset) % SHARD_COUNT + + return [ + ( + shuffling[committees_per_slot * offset + i], + (slot_start_shard + i) % SHARD_COUNT, + ) + for i in range(committees_per_slot) + ] +``` + +**Note**: we plan to replace the shuffling algorithm with a pointwise-evaluable shuffle (see https://github.com/ethereum/eth2.0-specs/issues/323), which will allow calculation of the committees for each slot individually. + +### `get_block_root` + +```python +def get_block_root(state: BeaconState, + slot: SlotNumber) -> Bytes32: + """ + Returns the block root at a recent ``slot``. + """ + assert state.slot <= slot + LATEST_BLOCK_ROOTS_LENGTH + assert slot < state.slot + return state.latest_block_roots[slot % LATEST_BLOCK_ROOTS_LENGTH] +``` + +`get_block_root(_, s)` should always return `hash_tree_root` of the block in the beacon chain at slot `s`, and `get_crosslink_committees_at_slot(_, s)` should not change unless the [validator](#dfn-validator) registry changes. + +### `get_randao_mix` + +```python +def get_randao_mix(state: BeaconState, + epoch: EpochNumber) -> Bytes32: + """ + Returns the randao mix at a recent ``epoch``. + """ + assert get_current_epoch(state) - LATEST_RANDAO_MIXES_LENGTH < epoch <= get_current_epoch(state) + return state.latest_randao_mixes[epoch % LATEST_RANDAO_MIXES_LENGTH] +``` + +### `get_active_index_root` + +```python +def get_active_index_root(state: BeaconState, + epoch: EpochNumber) -> Bytes32: + """ + Returns the index root at a recent ``epoch``. + """ + assert get_current_epoch(state) - LATEST_INDEX_ROOTS_LENGTH < epoch <= get_current_epoch(state) + return state.latest_index_roots[epoch % LATEST_INDEX_ROOTS_LENGTH] +``` + +### `generate_seed` + +```python +def generate_seed(state: BeaconState, + epoch: EpochNumber) -> Bytes32: + """ + Generate a seed for the given ``epoch``. + """ + + return hash( + get_randao_mix(state, epoch - SEED_LOOKAHEAD) + + get_active_index_root(state, epoch) + ) +``` + +### `get_beacon_proposer_index` + +```python +def get_beacon_proposer_index(state: BeaconState, + slot: SlotNumber) -> ValidatorIndex: + """ + Returns the beacon proposer index for the ``slot``. + """ + first_committee, _ = get_crosslink_committees_at_slot(state, slot)[0] + return first_committee[slot % len(first_committee)] +``` + +### `merkle_root` + +```python +def merkle_root(values: List[Bytes32]) -> Bytes32: + """ + Merkleize ``values`` (where ``len(values)`` is a power of two) and return the Merkle root. + """ + o = [0] * len(values) + values + for i in range(len(values) - 1, 0, -1): + o[i] = hash(o[i * 2] + o[i * 2 + 1]) + return o[1] +``` + +### `get_attestation_participants` + +```python +def get_attestation_participants(state: BeaconState, + attestation_data: AttestationData, + aggregation_bitfield: bytes) -> List[ValidatorIndex]: + """ + Returns the participant indices at for the ``attestation_data`` and ``aggregation_bitfield``. + """ + + # Find the committee in the list with the desired shard + crosslink_committees = get_crosslink_committees_at_slot(state, attestation_data.slot) + + assert attestation_data.shard in [shard for _, shard in crosslink_committees] + crosslink_committee = [committee for committee, shard in crosslink_committees if shard == attestation_data.shard][0] + assert len(aggregation_bitfield) == (len(crosslink_committee) + 7) // 8 + + # Find the participating attesters in the committee + participants = [] + for i, validator_index in enumerate(crosslink_committee): + aggregation_bit = (aggregation_bitfield[i // 8] >> (7 - (i % 8))) % 2 + if aggregation_bit == 1: + participants.append(validator_index) + return participants +``` + +### `int_to_bytes1`, `int_to_bytes2`, ... + +`int_to_bytes1(x): return x.to_bytes(1, 'big')`, `int_to_bytes2(x): return x.to_bytes(2, 'big')`, and so on for all integers, particularly 1, 2, 3, 4, 8, 32, 48, 96. + +### `get_effective_balance` + +```python +def get_effective_balance(state: State, index: ValidatorIndex) -> Gwei: + """ + Returns the effective balance (also known as "balance at stake") for a ``validator`` with the given ``index``. + """ + return min(state.validator_balances[index], MAX_DEPOSIT_AMOUNT) +``` + +### `get_fork_version` + +```python +def get_fork_version(fork: Fork, + epoch: EpochNumber) -> int: + if epoch < fork.epoch: + return fork.previous_version + else: + return fork.current_version +``` + +### `get_domain` + +```python +def get_domain(fork: Fork, + epoch: EpochNumber, + domain_type: int) -> int: + return get_fork_version( + fork, + epoch, + ) * 2**32 + domain_type +``` + +### `verify_slashable_vote_data` + +```python +def verify_slashable_vote_data(state: BeaconState, vote_data: SlashableVoteData) -> bool: + if len(vote_data.custody_bit_0_indices) + len(vote_data.custody_bit_1_indices) > MAX_CASPER_VOTES: + return False + + return bls_verify_multiple( + pubkeys=[ + bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in vote_data.custody_bit_0_indices]), + bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in vote_data.custody_bit_1_indices]), + ], + messages=[ + hash_tree_root(AttestationDataAndCustodyBit(vote_data.data, False)), + hash_tree_root(AttestationDataAndCustodyBit(vote_data.data, True)), + ], + signature=vote_data.aggregate_signature, + domain=get_domain( + state.fork, + slot_to_epoch(vote_data.data.slot), + DOMAIN_ATTESTATION, + ), + ) +``` + +### `is_double_vote` + +```python +def is_double_vote(attestation_data_1: AttestationData, + attestation_data_2: AttestationData) -> bool + """ + Assumes ``attestation_data_1`` is distinct from ``attestation_data_2``. + Returns True if the provided ``AttestationData`` are slashable + due to a 'double vote'. + """ + target_epoch_1 = slot_to_epoch(attestation_data_1.slot) + target_epoch_2 = slot_to_epoch(attestation_data_2.slot) + return target_epoch_1 == target_epoch_2 +``` + +### `is_surround_vote` + +```python +def is_surround_vote(attestation_data_1: AttestationData, + attestation_data_2: AttestationData) -> bool: + """ + Assumes ``attestation_data_1`` is distinct from ``attestation_data_2``. + Returns True if the provided ``AttestationData`` are slashable + due to a 'surround vote'. + Note: parameter order matters as this function only checks + that ``attestation_data_1`` surrounds ``attestation_data_2``. + """ + source_epoch_1 = attestation_data_1.justified_epoch + source_epoch_2 = attestation_data_2.justified_epoch + target_epoch_1 = slot_to_epoch(attestation_data_1.slot) + target_epoch_2 = slot_to_epoch(attestation_data_2.slot) + return ( + (source_epoch_1 < source_epoch_2) and + (source_epoch_2 + 1 == target_epoch_2) and + (target_epoch_2 < target_epoch_1) + ) +``` + +### `integer_squareroot` + +```python +def integer_squareroot(n: int) -> int: + """ + The largest integer ``x`` such that ``x**2`` is less than or equal to ``n``. + """ + assert n >= 0 + x = n + y = (x + 1) // 2 + while y < x: + x = y + y = (x + n // x) // 2 + return x +``` + +### `get_entry_exit_effect_epoch` + +```python +def get_entry_exit_effect_epoch(epoch: EpochNumber) -> EpochNumber: + """ + An entry or exit triggered in the ``epoch`` given by the input takes effect at + the epoch given by the output. + """ + return epoch + 1 + ENTRY_EXIT_DELAY +``` + +### `bls_verify` + +`bls_verify` is a function for verifying a BLS signature, defined in the [BLS Signature spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/bls_signature.md#bls_verify). + +### `bls_verify_multiple` + +`bls_verify_multiple` is a function for verifying a BLS signature constructed from multiple messages, defined in the [BLS Signature spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/bls_signature.md#bls_verify_multiple). + +### `bls_aggregate_pubkeys` + +`bls_aggregate_pubkeys` is a function for aggregating multiple BLS public keys into a single aggregate key, defined in the [BLS Signature spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/bls_signature.md#bls_aggregate_pubkeys). + + +### `validate_proof_of_possession` + +```python +def validate_proof_of_possession(state: BeaconState, + pubkey: BLSPubkey, + proof_of_possession: BLSSignature, + withdrawal_credentials: Bytes32) -> bool: + proof_of_possession_data = DepositInput( + pubkey=pubkey, + withdrawal_credentials=withdrawal_credentials, + proof_of_possession=EMPTY_SIGNATURE, + ) + + return bls_verify( + pubkey=pubkey, + message=hash_tree_root(proof_of_possession_data), + signature=proof_of_possession, + domain=get_domain( + state.fork, + get_current_epoch(state), + DOMAIN_DEPOSIT, + ) + ) +``` + +### `process_deposit` + +Used to add a [validator](#dfn-validator) or top up an existing [validator](#dfn-validator)'s balance by some `deposit` amount: + +```python +def process_deposit(state: BeaconState, + pubkey: BLSPubkey, + amount: Gwei, + proof_of_possession: BLSSignature, + withdrawal_credentials: Bytes32) -> None: + """ + Process a deposit from Ethereum 1.0. + Note that this function mutates ``state``. + """ + # Validate the given `proof_of_possession` + assert validate_proof_of_possession( + state, + pubkey, + proof_of_possession, + withdrawal_credentials, + ) + + validator_pubkeys = [v.pubkey for v in state.validator_registry] + + if pubkey not in validator_pubkeys: + # Add new validator + validator = Validator( + pubkey=pubkey, + withdrawal_credentials=withdrawal_credentials, + activation_epoch=FAR_FUTURE_EPOCH, + exit_epoch=FAR_FUTURE_EPOCH, + withdrawal_epoch=FAR_FUTURE_EPOCH, + penalized_epoch=FAR_FUTURE_EPOCH, + exit_count=0, + status_flags=0, + latest_custody_reseed_slot=GENESIS_SLOT, + penultimate_custody_reseed_slot=GENESIS_SLOT, + ) + + # Note: In phase 2 registry indices that have been withdrawn for a long time will be recycled. + state.validator_registry.append(validator) + state.validator_balances.append(amount) + else: + # Increase balance by deposit amount + index = validator_pubkeys.index(pubkey) + assert state.validator_registry[index].withdrawal_credentials == withdrawal_credentials + + state.validator_balances[index] += amount +``` + +### Routines for updating validator status + +Note: All functions in this section mutate `state`. + +#### `activate_validator` + +```python +def activate_validator(state: BeaconState, index: ValidatorIndex, genesis: bool) -> None: + validator = state.validator_registry[index] + + validator.activation_epoch = GENESIS_EPOCH if genesis else get_entry_exit_effect_epoch(get_current_epoch(state)) +``` + +#### `initiate_validator_exit` + +```python +def initiate_validator_exit(state: BeaconState, index: ValidatorIndex) -> None: + validator = state.validator_registry[index] + validator.status_flags |= INITIATED_EXIT +``` + +#### `exit_validator` + +```python +def exit_validator(state: BeaconState, index: ValidatorIndex) -> None: + validator = state.validator_registry[index] + + # The following updates only occur if not previous exited + if validator.exit_epoch <= get_entry_exit_effect_epoch(get_current_epoch(state)): + return + + validator.exit_epoch = get_entry_exit_effect_epoch(get_current_epoch(state)) + + state.validator_registry_exit_count += 1 + validator.exit_count = state.validator_registry_exit_count +``` + +#### `penalize_validator` + +```python +def penalize_validator(state: BeaconState, index: ValidatorIndex) -> None: + exit_validator(state, index) + validator = state.validator_registry[index] + state.latest_penalized_balances[get_current_epoch(state) % LATEST_PENALIZED_EXIT_LENGTH] += get_effective_balance(state, index) + + whistleblower_index = get_beacon_proposer_index(state, state.slot) + whistleblower_reward = get_effective_balance(state, index) // WHISTLEBLOWER_REWARD_QUOTIENT + state.validator_balances[whistleblower_index] += whistleblower_reward + state.validator_balances[index] -= whistleblower_reward + validator.penalized_epoch = get_current_epoch(state) +``` + +#### `prepare_validator_for_withdrawal` + +```python +def prepare_validator_for_withdrawal(state: BeaconState, index: ValidatorIndex) -> None: + validator = state.validator_registry[index] + validator.status_flags |= WITHDRAWABLE +``` + ## Ethereum 1.0 deposit contract The initial deployment phases of Ethereum 2.0 are implemented without consensus changes to Ethereum 1.0. A deposit contract at address `DEPOSIT_CONTRACT_ADDRESS` is added to Ethereum 1.0 for deposits of ETH to the beacon chain. Validator balances will be withdrawable to the shards in phase 2, i.e. when the EVM2.0 is deployed and the shards have state. @@ -715,553 +1331,7 @@ def get_branch(leaf: uint256) -> bytes32[32]: # size is DEPOSIT_CONTRACT_TREE_DE return branch ``` -## Beacon chain processing - -The beacon chain is the system chain for Ethereum 2.0. The main responsibilities of the beacon chain are: - -* Store and maintain the registry of [validators](#dfn-validator) -* Process crosslinks (see above) -* Process its per-slot consensus, as well as the finality gadget - -Processing the beacon chain is similar to processing the Ethereum 1.0 chain. Clients download and process blocks, and maintain a view of what is the current "canonical chain", terminating at the current "head". However, because of the beacon chain's relationship with Ethereum 1.0, and because it is a proof-of-stake chain, there are differences. - -For a beacon chain block, `block`, to be processed by a node, the following conditions must be met: - -* The parent block with root `block.parent_root` has been processed and accepted. -* The node has processed its `state` up to slot, `block.slot - 1`. -* An Ethereum 1.0 block pointed to by the `state.latest_eth1_data.block_hash` has been processed and accepted. -* The node's local clock time is greater than or equal to `state.genesis_time + block.slot * SLOT_DURATION`. - -If these conditions are not met, the client should delay processing the beacon block until the conditions are all satisfied. - -Beacon block production is significantly different because of the proof of stake mechanism. A client simply checks what it thinks is the canonical chain when it should create a block, and looks up what its slot number is; when the slot arrives, it either proposes or attests to a block as required. Note that this requires each node to have a clock that is roughly (i.e. within `SLOT_DURATION` seconds) synchronized with the other nodes. - -### Beacon chain fork choice rule - -The beacon chain fork choice rule is a hybrid that combines justification and finality with Latest Message Driven (LMD) Greediest Heaviest Observed SubTree (GHOST). At any point in time a [validator](#dfn-validator) `v` subjectively calculates the beacon chain head as follows. - -* Abstractly define `Store` as the type of storage object for the chain data and `store` be the set of attestations and blocks that the [validator](#dfn-validator) `v` has observed and verified (in particular, block ancestors must be recursively verified). Attestations not yet included in any chain are still included in `store`. -* Let `finalized_head` be the finalized block with the highest epoch. (A block `B` is finalized if there is a descendant of `B` in `store` the processing of which sets `B` as finalized.) -* Let `justified_head` be the descendant of `finalized_head` with the highest epoch that has been justified for at least 1 epoch. (A block `B` is justified if there is a descendant of `B` in `store` the processing of which sets `B` as justified.) If no such descendant exists set `justified_head` to `finalized_head`. -* Let `get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBlock` be the ancestor of `block` with slot number `slot`. The `get_ancestor` function can be defined recursively as `def get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBlock: return block if block.slot == slot else get_ancestor(store, store.get_parent(block), slot)`. -* Let `get_latest_attestation(store: Store, validator: Validator) -> Attestation` be the attestation with the highest slot number in `store` from `validator`. If several such attestations exist, use the one the [validator](#dfn-validator) `v` observed first. -* Let `get_latest_attestation_target(store: Store, validator: Validator) -> BeaconBlock` be the target block in the attestation `get_latest_attestation(store, validator)`. -* Let `get_children(store: Store, block: BeaconBlock) -> List[BeaconBlock]` returns the child blocks of the given `block`. -* Let `justified_head_state` be the resulting `BeaconState` object from processing the chain up to the `justified_head`. -* The `head` is `lmd_ghost(store, justified_head_state, justified_head)` where the function `lmd_ghost` is defined below. Note that the implementation below is suboptimal; there are implementations that compute the head in time logarithmic in slot count. - -```python -def lmd_ghost(store: Store, start_state: BeaconState, start_block: BeaconBlock) -> BeaconBlock: - validators = start_state.validator_registry - active_validators = [ - validators[i] - for i in get_active_validator_indices(validators, start_state.slot) - ] - attestation_targets = [ - get_latest_attestation_target(store, validator) - for validator in active_validators - ] - - def get_vote_count(block: BeaconBlock) -> int: - return len([ - target - for target in attestation_targets - if get_ancestor(store, target, block.slot) == block - ]) - - head = start_block - while 1: - children = get_children(store, head) - if len(children) == 0: - return head - head = max(children, key=get_vote_count) -``` - -## Beacon chain state transition function - -We now define the state transition function. At a high level the state transition is made up of three parts: - -1. The per-slot transitions, which happens every slot. -2. The per-block transitions, which happens at every block. -3. The per-epoch transitions, which happens at every epoch boundary (i.e. `(state.slot + 1) % EPOCH_LENGTH == 0`). - -The per-slot transitions focus on the slot counter and block roots records updates; the per-block transitions generally focus on verifying aggregate signatures and saving temporary records relating to the per-block activity in the `BeaconState`; the per-epoch transitions focus on the [validator](#dfn-validator) registry, including adjusting balances and activating and exiting [validators](#dfn-validator), as well as processing crosslinks and managing block justification/finalization. - -### Helper functions - -Note: The definitions below are for specification purposes and are not necessarily optimal implementations. - -#### `hash` - -The hash function is denoted by `hash`. In Phase 0 the beacon chain is deployed with the same hash function as Ethereum 1.0, i.e. Keccak-256 (also incorrectly known as SHA3). - -Note: We aim to migrate to a S[T/N]ARK-friendly hash function in a future Ethereum 2.0 deployment phase. - -#### `hash_tree_root` - -`def hash_tree_root(object: SSZSerializable) -> Bytes32` is a function for hashing objects into a single root utilizing a hash tree structure. `hash_tree_root` is defined in the [SimpleSerialize spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/simple-serialize.md#tree-hash). - -#### `slot_to_epoch` - -```python -def slot_to_epoch(slot: SlotNumber) -> EpochNumber: - return slot // EPOCH_LENGTH -``` - -#### `get_current_epoch` - -```python -def get_current_epoch(state: BeaconState) -> EpochNumber: - return slot_to_epoch(state.slot) -``` - -#### `get_epoch_start_slot` - -```python -def get_epoch_start_slot(epoch: EpochNumber) -> SlotNumber: - return epoch * EPOCH_LENGTH -``` - -#### `is_active_validator` -```python -def is_active_validator(validator: Validator, epoch: EpochNumber) -> bool: - """ - Checks if ``validator`` is active. - """ - return validator.activation_epoch <= epoch < validator.exit_epoch -``` - -#### `get_active_validator_indices` - -```python -def get_active_validator_indices(validators: List[Validator], epoch: EpochNumber) -> List[ValidatorIndex]: - """ - Gets indices of active validators from ``validators``. - """ - return [i for i, v in enumerate(validators) if is_active_validator(v, epoch)] -``` - -#### `shuffle` - -```python -def shuffle(values: List[Any], seed: Bytes32) -> List[Any]: - """ - Returns the shuffled ``values`` with ``seed`` as entropy. - """ - values_count = len(values) - - # Entropy is consumed from the seed in 3-byte (24 bit) chunks. - rand_bytes = 3 - # The highest possible result of the RNG. - rand_max = 2 ** (rand_bytes * 8) - 1 - - # The range of the RNG places an upper-bound on the size of the list that - # may be shuffled. It is a logic error to supply an oversized list. - assert values_count < rand_max - - output = [x for x in values] - source = seed - index = 0 - while index < values_count - 1: - # Re-hash the `source` to obtain a new pattern of bytes. - source = hash(source) - # Iterate through the `source` bytes in 3-byte chunks. - for position in range(0, 32 - (32 % rand_bytes), rand_bytes): - # Determine the number of indices remaining in `values` and exit - # once the last index is reached. - remaining = values_count - index - if remaining == 1: - break - - # Read 3-bytes of `source` as a 24-bit big-endian integer. - sample_from_source = int.from_bytes(source[position:position + rand_bytes], 'big') - - # Sample values greater than or equal to `sample_max` will cause - # modulo bias when mapped into the `remaining` range. - sample_max = rand_max - rand_max % remaining - - # Perform a swap if the consumed entropy will not cause modulo bias. - if sample_from_source < sample_max: - # Select a replacement index for the current index. - replacement_position = (sample_from_source % remaining) + index - # Swap the current index with the replacement index. - output[index], output[replacement_position] = output[replacement_position], output[index] - index += 1 - else: - # The sample causes modulo bias. A new sample should be read. - pass - - return output -``` - -#### `split` - -```python -def split(values: List[Any], split_count: int) -> List[List[Any]]: - """ - Splits ``values`` into ``split_count`` pieces. - """ - list_length = len(values) - return [ - values[(list_length * i // split_count): (list_length * (i + 1) // split_count)] - for i in range(split_count) - ] -``` - -#### `get_epoch_committee_count` - -```python -def get_epoch_committee_count(active_validator_count: int) -> int: - return max( - 1, - min( - SHARD_COUNT // EPOCH_LENGTH, - active_validator_count // EPOCH_LENGTH // TARGET_COMMITTEE_SIZE, - ) - ) * EPOCH_LENGTH -``` - -#### `get_shuffling` - -```python -def get_shuffling(seed: Bytes32, - validators: List[Validator], - epoch: EpochNumber) -> List[List[ValidatorIndex]] - """ - Shuffles ``validators`` into crosslink committees seeded by ``seed`` and ``epoch``. - Returns a list of ``committees_per_epoch`` committees where each - committee is itself a list of validator indices. - """ - - active_validator_indices = get_active_validator_indices(validators, epoch) - - committees_per_epoch = get_epoch_committee_count(len(active_validator_indices)) - - # Shuffle - seed = xor(seed, int_to_bytes32(epoch)) - shuffled_active_validator_indices = shuffle(active_validator_indices, seed) - - # Split the shuffled list into committees_per_epoch pieces - return split(shuffled_active_validator_indices, committees_per_epoch) -``` - -**Invariant**: if `get_shuffling(seed, validators, epoch)` returns some value `x` for some `epoch <= get_current_epoch(state) + ENTRY_EXIT_DELAY`, it should return the same value `x` for the same `seed` and `epoch` and possible future modifications of `validators` forever in phase 0, and until the ~1 year deletion delay in phase 2 and in the future. - -**Note**: this definition and the next few definitions make heavy use of repetitive computing. Production implementations are expected to appropriately use caching/memoization to avoid redoing work. - -#### `get_previous_epoch_committee_count` - -```python -def get_previous_epoch_committee_count(state: BeaconState) -> int: - previous_active_validators = get_active_validator_indices( - state.validator_registry, - state.previous_calculation_epoch, - ) - return get_epoch_committee_count(len(previous_active_validators)) -``` - -#### `get_current_epoch_committee_count` - -```python -def get_current_epoch_committee_count(state: BeaconState) -> int: - current_active_validators = get_active_validator_indices( - state.validator_registry, - state.current_calculation_epoch, - ) - return get_epoch_committee_count(len(current_active_validators)) -``` - -#### `get_crosslink_committees_at_slot` - -```python -def get_crosslink_committees_at_slot(state: BeaconState, - slot: SlotNumber) -> List[Tuple[List[ValidatorIndex], ShardNumber]]: - """ - Returns the list of ``(committee, shard)`` tuples for the ``slot``. - """ - epoch = slot_to_epoch(slot) - current_epoch = get_current_epoch(state) - previous_epoch = current_epoch - 1 if current_epoch > GENESIS_EPOCH else current_epoch - next_epoch = current_epoch + 1 - - assert previous_epoch <= epoch < next_epoch - - if epoch < current_epoch: - committees_per_epoch = get_previous_epoch_committee_count(state) - seed = state.previous_epoch_seed - shuffling_epoch = state.previous_calculation_epoch - shuffling_start_shard = state.previous_epoch_start_shard - else: - committees_per_epoch = get_current_epoch_committee_count(state) - seed = state.current_epoch_seed - shuffling_epoch = state.current_calculation_epoch - shuffling_start_shard = state.current_epoch_start_shard - - shuffling = get_shuffling( - seed, - state.validator_registry, - shuffling_epoch, - ) - offset = slot % EPOCH_LENGTH - committees_per_slot = committees_per_epoch // EPOCH_LENGTH - slot_start_shard = (shuffling_start_shard + committees_per_slot * offset) % SHARD_COUNT - - return [ - ( - shuffling[committees_per_slot * offset + i], - (slot_start_shard + i) % SHARD_COUNT, - ) - for i in range(committees_per_slot) - ] -``` - -**Note**: we plan to replace the shuffling algorithm with a pointwise-evaluable shuffle (see https://github.com/ethereum/eth2.0-specs/issues/323), which will allow calculation of the committees for each slot individually. - -#### `get_block_root` - -```python -def get_block_root(state: BeaconState, - slot: SlotNumber) -> Bytes32: - """ - Returns the block root at a recent ``slot``. - """ - assert state.slot <= slot + LATEST_BLOCK_ROOTS_LENGTH - assert slot < state.slot - return state.latest_block_roots[slot % LATEST_BLOCK_ROOTS_LENGTH] -``` - -`get_block_root(_, s)` should always return `hash_tree_root` of the block in the beacon chain at slot `s`, and `get_crosslink_committees_at_slot(_, s)` should not change unless the [validator](#dfn-validator) registry changes. - -#### `get_randao_mix` - -```python -def get_randao_mix(state: BeaconState, - epoch: EpochNumber) -> Bytes32: - """ - Returns the randao mix at a recent ``epoch``. - """ - assert get_current_epoch(state) - LATEST_RANDAO_MIXES_LENGTH < epoch <= get_current_epoch(state) - return state.latest_randao_mixes[epoch % LATEST_RANDAO_MIXES_LENGTH] -``` - -#### `get_active_index_root` - -```python -def get_active_index_root(state: BeaconState, - epoch: EpochNumber) -> Bytes32: - """ - Returns the index root at a recent ``epoch``. - """ - assert get_current_epoch(state) - LATEST_INDEX_ROOTS_LENGTH < epoch <= get_current_epoch(state) - return state.latest_index_roots[epoch % LATEST_INDEX_ROOTS_LENGTH] -``` - -#### `generate_seed` - -```python -def generate_seed(state: BeaconState, - epoch: EpochNumber) -> Bytes32: - """ - Generate a seed for the given ``epoch``. - """ - - return hash( - get_randao_mix(state, epoch - SEED_LOOKAHEAD) + - get_active_index_root(state, epoch) - ) -``` - -#### `get_beacon_proposer_index` - -```python -def get_beacon_proposer_index(state: BeaconState, - slot: SlotNumber) -> ValidatorIndex: - """ - Returns the beacon proposer index for the ``slot``. - """ - first_committee, _ = get_crosslink_committees_at_slot(state, slot)[0] - return first_committee[slot % len(first_committee)] -``` - -#### `merkle_root` - -```python -def merkle_root(values: List[Bytes32]) -> Bytes32: - """ - Merkleize ``values`` (where ``len(values)`` is a power of two) and return the Merkle root. - """ - o = [0] * len(values) + values - for i in range(len(values) - 1, 0, -1): - o[i] = hash(o[i * 2] + o[i * 2 + 1]) - return o[1] -``` - -#### `get_attestation_participants` - -```python -def get_attestation_participants(state: BeaconState, - attestation_data: AttestationData, - aggregation_bitfield: bytes) -> List[ValidatorIndex]: - """ - Returns the participant indices at for the ``attestation_data`` and ``aggregation_bitfield``. - """ - - # Find the committee in the list with the desired shard - crosslink_committees = get_crosslink_committees_at_slot(state, attestation_data.slot) - - assert attestation_data.shard in [shard for _, shard in crosslink_committees] - crosslink_committee = [committee for committee, shard in crosslink_committees if shard == attestation_data.shard][0] - assert len(aggregation_bitfield) == (len(crosslink_committee) + 7) // 8 - - # Find the participating attesters in the committee - participants = [] - for i, validator_index in enumerate(crosslink_committee): - aggregation_bit = (aggregation_bitfield[i // 8] >> (7 - (i % 8))) % 2 - if aggregation_bit == 1: - participants.append(validator_index) - return participants -``` - -#### `int_to_bytes1`, `int_to_bytes2`, ... - -`int_to_bytes1(x): return x.to_bytes(1, 'big')`, `int_to_bytes2(x): return x.to_bytes(2, 'big')`, and so on for all integers, particularly 1, 2, 3, 4, 8, 32, 48, 96. - -#### `get_effective_balance` - -```python -def get_effective_balance(state: State, index: ValidatorIndex) -> Gwei: - """ - Returns the effective balance (also known as "balance at stake") for a ``validator`` with the given ``index``. - """ - return min(state.validator_balances[index], MAX_DEPOSIT_AMOUNT) -``` - -#### `get_fork_version` - -```python -def get_fork_version(fork: Fork, - epoch: EpochNumber) -> int: - if epoch < fork.epoch: - return fork.previous_version - else: - return fork.current_version -``` - -#### `get_domain` - -```python -def get_domain(fork: Fork, - epoch: EpochNumber, - domain_type: int) -> int: - return get_fork_version( - fork, - epoch, - ) * 2**32 + domain_type -``` - -#### `verify_slashable_vote_data` - -```python -def verify_slashable_vote_data(state: BeaconState, vote_data: SlashableVoteData) -> bool: - if len(vote_data.custody_bit_0_indices) + len(vote_data.custody_bit_1_indices) > MAX_CASPER_VOTES: - return False - - return bls_verify_multiple( - pubkeys=[ - bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in vote_data.custody_bit_0_indices]), - bls_aggregate_pubkeys([state.validator_registry[i].pubkey for i in vote_data.custody_bit_1_indices]), - ], - messages=[ - hash_tree_root(AttestationDataAndCustodyBit(vote_data.data, False)), - hash_tree_root(AttestationDataAndCustodyBit(vote_data.data, True)), - ], - signature=vote_data.aggregate_signature, - domain=get_domain( - state.fork, - slot_to_epoch(vote_data.data.slot), - DOMAIN_ATTESTATION, - ), - ) -``` - -#### `is_double_vote` - -```python -def is_double_vote(attestation_data_1: AttestationData, - attestation_data_2: AttestationData) -> bool - """ - Assumes ``attestation_data_1`` is distinct from ``attestation_data_2``. - Returns True if the provided ``AttestationData`` are slashable - due to a 'double vote'. - """ - target_epoch_1 = slot_to_epoch(attestation_data_1.slot) - target_epoch_2 = slot_to_epoch(attestation_data_2.slot) - return target_epoch_1 == target_epoch_2 -``` - -#### `is_surround_vote` - -```python -def is_surround_vote(attestation_data_1: AttestationData, - attestation_data_2: AttestationData) -> bool: - """ - Assumes ``attestation_data_1`` is distinct from ``attestation_data_2``. - Returns True if the provided ``AttestationData`` are slashable - due to a 'surround vote'. - Note: parameter order matters as this function only checks - that ``attestation_data_1`` surrounds ``attestation_data_2``. - """ - source_epoch_1 = attestation_data_1.justified_epoch - source_epoch_2 = attestation_data_2.justified_epoch - target_epoch_1 = slot_to_epoch(attestation_data_1.slot) - target_epoch_2 = slot_to_epoch(attestation_data_2.slot) - return ( - (source_epoch_1 < source_epoch_2) and - (source_epoch_2 + 1 == target_epoch_2) and - (target_epoch_2 < target_epoch_1) - ) -``` - -#### `integer_squareroot` - -```python -def integer_squareroot(n: int) -> int: - """ - The largest integer ``x`` such that ``x**2`` is less than or equal to ``n``. - """ - assert n >= 0 - x = n - y = (x + 1) // 2 - while y < x: - x = y - y = (x + n // x) // 2 - return x -``` - -#### `get_entry_exit_effect_epoch` - -```python -def get_entry_exit_effect_epoch(epoch: EpochNumber) -> EpochNumber: - """ - An entry or exit triggered in the ``epoch`` given by the input takes effect at - the epoch given by the output. - """ - return epoch + 1 + ENTRY_EXIT_DELAY -``` - -#### `bls_verify` - -`bls_verify` is a function for verifying a BLS signature, defined in the [BLS Signature spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/bls_signature.md#bls_verify). - -#### `bls_verify_multiple` - -`bls_verify_multiple` is a function for verifying a BLS signature constructed from multiple messages, defined in the [BLS Signature spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/bls_signature.md#bls_verify_multiple). - -#### `bls_aggregate_pubkeys` - -`bls_aggregate_pubkeys` is a function for aggregating multiple BLS public keys into a single aggregate key, defined in the [BLS Signature spec](https://github.com/ethereum/eth2.0-specs/blob/master/specs/bls_signature.md#bls_aggregate_pubkeys). - -### On startup +## On startup A valid block with slot `GENESIS_SLOT` (a "genesis block") has the following values. Other validity rules (e.g. requiring a signature) do not apply. @@ -1364,173 +1434,121 @@ def get_initial_beacon_state(initial_validator_deposits: List[Deposit], return state ``` -### Routine for processing deposits +## Beacon chain processing -First, a helper function: +The beacon chain is the system chain for Ethereum 2.0. The main responsibilities of the beacon chain are: + +* Store and maintain the registry of [validators](#dfn-validator) +* Process crosslinks (see above) +* Process its per-block consensus, as well as the finality gadget + +Processing the beacon chain is similar to processing the Ethereum 1.0 chain. Clients download and process blocks, and maintain a view of what is the current "canonical chain", terminating at the current "head". However, because of the beacon chain's relationship with Ethereum 1.0, and because it is a proof-of-stake chain, there are differences. + +For a beacon chain block, `block`, to be processed by a node, the following conditions must be met: + +* The parent block with root `block.parent_root` has been processed and accepted. +* An Ethereum 1.0 block pointed to by the `state.latest_eth1_data.block_hash` has been processed and accepted. +* The node's local clock time is greater than or equal to `state.genesis_time + block.slot * SLOT_DURATION`. + +If these conditions are not met, the client should delay processing the beacon block until the conditions are all satisfied. + +Beacon block production is significantly different because of the proof of stake mechanism. A client simply checks what it thinks is the canonical chain when it should create a block, and looks up what its slot number is; when the slot arrives, it either proposes or attests to a block as required. Note that this requires each node to have a clock that is roughly (i.e. within `SLOT_DURATION` seconds) synchronized with the other nodes. + +### Beacon chain fork choice rule + +The beacon chain fork choice rule is a hybrid that combines justification and finality with Latest Message Driven (LMD) Greediest Heaviest Observed SubTree (GHOST). At any point in time a [validator](#dfn-validator) `v` subjectively calculates the beacon chain head as follows. + +* Abstractly define `Store` as the type of storage object for the chain data and `store` be the set of attestations and blocks that the [validator](#dfn-validator) `v` has observed and verified (in particular, block ancestors must be recursively verified). Attestations not yet included in any chain are still included in `store`. +* Let `finalized_head` be the finalized block with the highest epoch. (A block `B` is finalized if there is a descendant of `B` in `store` the processing of which sets `B` as finalized.) +* Let `justified_head` be the descendant of `finalized_head` with the highest epoch that has been justified for at least 1 epoch. (A block `B` is justified if there is a descendant of `B` in `store` the processing of which sets `B` as justified.) If no such descendant exists set `justified_head` to `finalized_head`. +* Let `get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBlock` be the ancestor of `block` with slot number `slot`. The `get_ancestor` function can be defined recursively as `def get_ancestor(store: Store, block: BeaconBlock, slot: SlotNumber) -> BeaconBlock: return block if block.slot == slot else get_ancestor(store, store.get_parent(block), slot)`. +* Let `get_latest_attestation(store: Store, validator: Validator) -> Attestation` be the attestation with the highest slot number in `store` from `validator`. If several such attestations exist, use the one the [validator](#dfn-validator) `v` observed first. +* Let `get_latest_attestation_target(store: Store, validator: Validator) -> BeaconBlock` be the target block in the attestation `get_latest_attestation(store, validator)`. +* Let `get_children(store: Store, block: BeaconBlock) -> List[BeaconBlock]` returns the child blocks of the given `block`. +* Let `justified_head_state` be the resulting `BeaconState` object from processing the chain up to the `justified_head`. +* The `head` is `lmd_ghost(store, justified_head_state, justified_head)` where the function `lmd_ghost` is defined below. Note that the implementation below is suboptimal; there are implementations that compute the head in time logarithmic in slot count. ```python -def validate_proof_of_possession(state: BeaconState, - pubkey: BLSPubkey, - proof_of_possession: BLSSignature, - withdrawal_credentials: Bytes32) -> bool: - proof_of_possession_data = DepositInput( - pubkey=pubkey, - withdrawal_credentials=withdrawal_credentials, - proof_of_possession=EMPTY_SIGNATURE, - ) +def lmd_ghost(store: Store, start_state: BeaconState, start_block: BeaconBlock) -> BeaconBlock: + validators = start_state.validator_registry + active_validators = [ + validators[i] + for i in get_active_validator_indices(validators, start_state.slot) + ] + attestation_targets = [ + get_latest_attestation_target(store, validator) + for validator in active_validators + ] - return bls_verify( - pubkey=pubkey, - message=hash_tree_root(proof_of_possession_data), - signature=proof_of_possession, - domain=get_domain( - state.fork, - get_current_epoch(state), - DOMAIN_DEPOSIT, - ) - ) + def get_vote_count(block: BeaconBlock) -> int: + return len([ + target + for target in attestation_targets + if get_ancestor(store, target, block.slot) == block + ]) + + head = start_block + while 1: + children = get_children(store, head) + if len(children) == 0: + return head + head = max(children, key=get_vote_count) ``` -Now, to add a [validator](#dfn-validator) or top up an existing [validator](#dfn-validator)'s balance by some `deposit` amount: +## Beacon chain state transition function -```python -def process_deposit(state: BeaconState, - pubkey: BLSPubkey, - amount: Gwei, - proof_of_possession: BLSSignature, - withdrawal_credentials: Bytes32) -> None: - """ - Process a deposit from Ethereum 1.0. - Note that this function mutates ``state``. - """ - # Validate the given `proof_of_possession` - assert validate_proof_of_possession( - state, - pubkey, - proof_of_possession, - withdrawal_credentials, - ) +We now define the state transition function. This is a parent to child block transition. At a high level the state transition is made up of three parts: - validator_pubkeys = [v.pubkey for v in state.validator_registry] +1. The per-slot transitions, which happens every slot. +2. The per-block transitions, which happens at every block. +3. The per-epoch transitions, which happens at every epoch boundary (i.e. `(state.slot + 1) % EPOCH_LENGTH == 0`). - if pubkey not in validator_pubkeys: - # Add new validator - validator = Validator( - pubkey=pubkey, - withdrawal_credentials=withdrawal_credentials, - activation_epoch=FAR_FUTURE_EPOCH, - exit_epoch=FAR_FUTURE_EPOCH, - withdrawal_epoch=FAR_FUTURE_EPOCH, - penalized_epoch=FAR_FUTURE_EPOCH, - exit_count=0, - status_flags=0, - latest_custody_reseed_slot=GENESIS_SLOT, - penultimate_custody_reseed_slot=GENESIS_SLOT, - ) +The per-slot transitions focus on the slot counter and block roots records updates; the per-block transitions generally focus on verifying aggregate signatures and saving temporary records relating to the per-block activity in the `BeaconState`; the per-epoch transitions focus on the [validator](#dfn-validator) registry, including adjusting balances and activating and exiting [validators](#dfn-validator), as well as processing crosslinks and managing block justification/finalization. - # Note: In phase 2 registry indices that have been withdrawn for a long time will be recycled. - state.validator_registry.append(validator) - state.validator_balances.append(amount) - else: - # Increase balance by deposit amount - index = validator_pubkeys.index(pubkey) - assert state.validator_registry[index].withdrawal_credentials == withdrawal_credentials +_Note_: If there are skipped slots between a block and its parent block, run the steps in the [per-slot](#per-slot-processing) and [per-epoch](#per-epoch-processing) sections once for each skipped slot and then once for the slot containing the new block. - state.validator_balances[index] += amount -``` +### Per-slot processing -### Routines for updating validator status +Below are the processing steps that happen at every slot. -Note: All functions in this section mutate `state`. - -```python -def activate_validator(state: BeaconState, index: ValidatorIndex, genesis: bool) -> None: - validator = state.validator_registry[index] - - validator.activation_epoch = GENESIS_EPOCH if genesis else get_entry_exit_effect_epoch(get_current_epoch(state)) -``` - -```python -def initiate_validator_exit(state: BeaconState, index: ValidatorIndex) -> None: - validator = state.validator_registry[index] - validator.status_flags |= INITIATED_EXIT -``` - -```python -def exit_validator(state: BeaconState, index: ValidatorIndex) -> None: - validator = state.validator_registry[index] - - # The following updates only occur if not previous exited - if validator.exit_epoch <= get_entry_exit_effect_epoch(get_current_epoch(state)): - return - - validator.exit_epoch = get_entry_exit_effect_epoch(get_current_epoch(state)) - - state.validator_registry_exit_count += 1 - validator.exit_count = state.validator_registry_exit_count -``` - -```python -def penalize_validator(state: BeaconState, index: ValidatorIndex) -> None: - exit_validator(state, index) - validator = state.validator_registry[index] - state.latest_penalized_balances[get_current_epoch(state) % LATEST_PENALIZED_EXIT_LENGTH] += get_effective_balance(state, index) - - whistleblower_index = get_beacon_proposer_index(state, state.slot) - whistleblower_reward = get_effective_balance(state, index) // WHISTLEBLOWER_REWARD_QUOTIENT - state.validator_balances[whistleblower_index] += whistleblower_reward - state.validator_balances[index] -= whistleblower_reward - validator.penalized_epoch = get_current_epoch(state) -``` - -```python -def prepare_validator_for_withdrawal(state: BeaconState, index: ValidatorIndex) -> None: - validator = state.validator_registry[index] - validator.status_flags |= WITHDRAWABLE -``` - -## Per-slot processing - -Below are the processing steps that happen at every slot. If there are skipped slots between a block and its parent block, run the steps in this section once for each skipped slot and then once for the slot containing the new block. - -### Slot +#### Slot * Set `state.slot += 1`. -### Block roots +#### Block roots * Let `previous_block_root` be the `tree_hash_root` of the previous beacon block processed in the chain. * Set `state.latest_block_roots[(state.slot - 1) % LATEST_BLOCK_ROOTS_LENGTH] = previous_block_root`. * If `state.slot % LATEST_BLOCK_ROOTS_LENGTH == 0` append `merkle_root(state.latest_block_roots)` to `state.batched_block_roots`. -## Per-block processing +### Per-block processing Below are the processing steps that happen at every `block`. -### Slot +#### Slot * Verify that `block.slot == state.slot`. -### Proposer signature +#### Proposer signature * Let `block_without_signature_root` be the `hash_tree_root` of `block` where `block.signature` is set to `EMPTY_SIGNATURE`. * Let `proposal_root = hash_tree_root(ProposalSignedData(state.slot, BEACON_CHAIN_SHARD_NUMBER, block_without_signature_root))`. * Verify that `bls_verify(pubkey=state.validator_registry[get_beacon_proposer_index(state, state.slot)].pubkey, message=proposal_root, signature=block.signature, domain=get_domain(state.fork, get_current_epoch(state), DOMAIN_PROPOSAL))`. -### RANDAO +#### RANDAO * Let `proposer = state.validator_registry[get_beacon_proposer_index(state, state.slot)]`. * Verify that `bls_verify(pubkey=proposer.pubkey, message=int_to_bytes32(get_current_epoch(state)), signature=block.randao_reveal, domain=get_domain(state.fork, get_current_epoch(state), DOMAIN_RANDAO))`. * Set `state.latest_randao_mixes[get_current_epoch(state) % LATEST_RANDAO_MIXES_LENGTH] = xor(get_randao_mix(state, get_current_epoch(state)), hash(block.randao_reveal))`. -### Eth1 data +#### Eth1 data * If `block.eth1_data` equals `eth1_data_vote.eth1_data` for some `eth1_data_vote` in `state.eth1_data_votes`, set `eth1_data_vote.vote_count += 1`. * Otherwise, append to `state.eth1_data_votes` a new `Eth1DataVote(eth1_data=block.eth1_data, vote_count=1)`. -### Operations +#### Operations -#### Proposer slashings +##### Proposer slashings Verify that `len(block.body.proposer_slashings) <= MAX_PROPOSER_SLASHINGS`. @@ -1545,7 +1563,7 @@ For each `proposer_slashing` in `block.body.proposer_slashings`: * Verify that `bls_verify(pubkey=proposer.pubkey, message=hash_tree_root(proposer_slashing.proposal_data_2), signature=proposer_slashing.proposal_signature_2, domain=get_domain(state.fork, slot_to_epoch(proposer_slashing.proposal_data_2.slot), DOMAIN_PROPOSAL))`. * Run `penalize_validator(state, proposer_slashing.proposer_index)`. -#### Attester slashings +##### Attester slashings Verify that `len(block.body.attester_slashings) <= MAX_ATTESTER_SLASHINGS`. @@ -1562,7 +1580,7 @@ For each `attester_slashing` in `block.body.attester_slashings`: * Verify that `verify_slashable_vote_data(state, slashable_vote_data_2)`. * For each [validator](#dfn-validator) index `i` in `intersection` run `penalize_validator(state, i)` if `state.validator_registry[i].penalized_epoch > get_current_epoch(state)`. -#### Attestations +##### Attestations Verify that `len(block.body.attestations) <= MAX_ATTESTATIONS`. @@ -1580,7 +1598,7 @@ For each `attestation` in `block.body.attestations`: * [TO BE REMOVED IN PHASE 1] Verify that `attestation.data.shard_block_root == ZERO_HASH`. * Append `PendingAttestation(data=attestation.data, aggregation_bitfield=attestation.aggregation_bitfield, custody_bitfield=attestation.custody_bitfield, slot_included=state.slot)` to `state.latest_attestations`. -#### Deposits +##### Deposits Verify that `len(block.body.deposits) <= MAX_DEPOSITS`. @@ -1615,7 +1633,7 @@ process_deposit( ) ``` -#### Exits +##### Exits Verify that `len(block.body.exits) <= MAX_EXITS`. @@ -1628,15 +1646,15 @@ For each `exit` in `block.body.exits`: * Verify that `bls_verify(pubkey=validator.pubkey, message=exit_message, signature=exit.signature, domain=get_domain(state.fork, exit.epoch, DOMAIN_EXIT))`. * Run `initiate_validator_exit(state, exit.validator_index)`. -#### Custody +##### Custody [TO BE REMOVED IN PHASE 1] Verify that `len(block.body.custody_reseeds) == len(block.body.custody_challenges) == len(block.body.custody_responses) == 0`. -## Per-epoch processing +### Per-epoch processing The steps below happen when `(state.slot + 1) % EPOCH_LENGTH == 0`. -### Helpers +#### Helpers * Let `current_epoch = get_current_epoch(state)`. * Let `previous_epoch = current_epoch - 1 if current_epoch > GENESIS_EPOCH else current_epoch`. @@ -1686,14 +1704,14 @@ Define the following helpers to process attestation inclusion rewards and inclus * Let `inclusion_slot(state, index) = a.slot_included` for the attestation `a` where `index` is in `get_attestation_participants(state, a.data, a.aggregation_bitfield)`. If multiple attestations are applicable, the attestation with lowest `slot_included` is considered. * Let `inclusion_distance(state, index) = a.slot_included - a.data.slot` where `a` is the above attestation. -### Eth1 data +#### Eth1 data If `next_epoch % ETH1_DATA_VOTING_PERIOD == 0`: * If `eth1_data_vote.vote_count * 2 > ETH1_DATA_VOTING_PERIOD * EPOCH_LENGTH` for some `eth1_data_vote` in `state.eth1_data_votes` (ie. more than half the votes in this voting period were for that value), set `state.latest_eth1_data = eth1_data_vote.data`. * Set `state.eth1_data_votes = []`. -### Justification +#### Justification First, update the justification bitfield: @@ -1714,13 +1732,13 @@ Finally, update the following: * Set `state.previous_justified_epoch = state.justified_epoch`. * Set `state.justified_epoch = new_justified_epoch`. -### Crosslinks +#### Crosslinks For every `slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_slot(next_epoch))`, let `crosslink_committees_at_slot = get_crosslink_committees_at_slot(state, slot)`. For every `(crosslink_committee, shard)` in `crosslink_committees_at_slot`, compute: * Set `state.latest_crosslinks[shard] = Crosslink(epoch=current_epoch, shard_block_root=winning_root(crosslink_committee))` if `3 * total_attesting_balance(crosslink_committee) >= 2 * total_balance(crosslink_committee)`. -### Rewards and penalties +#### Rewards and penalties First, we define some additional helpers: @@ -1728,7 +1746,7 @@ First, we define some additional helpers: * Let `base_reward(state, index) = get_effective_balance(state, index) // base_reward_quotient // 5` for any validator with the given `index`. * Let `inactivity_penalty(state, index, epochs_since_finality) = base_reward(state, index) + get_effective_balance(state, index) * epochs_since_finality // INACTIVITY_PENALTY_QUOTIENT // 2` for any validator with the given `index`. -#### Justification and finalization +##### Justification and finalization Note: When applying penalties in the following balance recalculations implementers should make sure the `uint64` does not underflow. @@ -1756,11 +1774,11 @@ Case 2: `epochs_since_finality > 4`: * Any [active_validator](#dfn-active-validator) `index` with `validator.penalized_epoch <= current_epoch`, loses `2 * inactivity_penalty(state, index, epochs_since_finality) + base_reward(state, index)`. * Any [validator](#dfn-validator) `index` in `previous_epoch_attester_indices` loses `base_reward(state, index) - base_reward(state, index) * MIN_ATTESTATION_INCLUSION_DELAY // inclusion_distance(state, index)` -#### Attestation inclusion +##### Attestation inclusion For each `index` in `previous_epoch_attester_indices`, we determine the proposer `proposer_index = get_beacon_proposer_index(state, inclusion_slot(state, index))` and set `state.validator_balances[proposer_index] += base_reward(state, index) // INCLUDER_REWARD_QUOTIENT`. -#### Crosslinks +##### Crosslinks For every `slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_slot(current_epoch))`: @@ -1769,7 +1787,7 @@ For every `slot in range(get_epoch_start_slot(previous_epoch), get_epoch_start_s * If `index in attesting_validators(crosslink_committee)`, `state.validator_balances[index] += base_reward(state, index) * total_attesting_balance(crosslink_committee) // total_balance(crosslink_committee))`. * If `index not in attesting_validators(crosslink_committee)`, `state.validator_balances[index] -= base_reward(state, index)`. -### Ejections +#### Ejections * Run `process_ejections(state)`. @@ -1784,7 +1802,7 @@ def process_ejections(state: BeaconState) -> None: exit_validator(state, index) ``` -### Validator registry and shuffling seed data +#### Validator registry and shuffling seed data First, update the following: @@ -1899,13 +1917,13 @@ def process_penalties_and_exits(state: BeaconState) -> None: break ``` -### Final updates +#### Final updates * Set `state.latest_penalized_balances[(next_epoch) % LATEST_PENALIZED_EXIT_LENGTH] = state.latest_penalized_balances[current_epoch % LATEST_PENALIZED_EXIT_LENGTH]`. * Set `state.latest_randao_mixes[next_epoch % LATEST_RANDAO_MIXES_LENGTH] = get_randao_mix(state, current_epoch)`. * Remove any `attestation` in `state.latest_attestations` such that `slot_to_epoch(attestation.data.slot) < current_epoch`. -## State root processing +### State root verification Verify `block.state_root == hash_tree_root(state)` if there exists a `block` for the slot being processed. From f51ce8ff14d2a4bbb00b88d8cd7183f8334ba593 Mon Sep 17 00:00:00 2001 From: Justin Date: Mon, 28 Jan 2019 19:16:11 +0000 Subject: [PATCH 63/70] Further deemphasize "Casper" --- specs/core/0_beacon-chain.md | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index c0e247108..1f2b53090 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -145,8 +145,8 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be ## Terminology -* **Validator** - a participant in the Casper/sharding consensus system. You can become one by depositing 32 ETH into the Casper mechanism. -* **Active validator** - a [validator](#dfn-validator) currently participating in the protocol which the Casper mechanism looks to produce and attest to blocks, crosslinks and other consensus objects. +* **Validator** - a registered participant in the beacon chain. You can become one by sending Ether into the Ethereum 1.0 deposit contract. +* **Active validator** - an active participant in the Ethereum 2.0 consensus invited to, among other things, propose and attest to blocks and vote for crosslinks. * **Committee** - a (pseudo-) randomly sampled subset of [active validators](#dfn-active-validator). When a committee is referred to collectively, as in "this committee attests to X", this is assumed to mean "some subset of that committee that contains enough [validators](#dfn-validator) that the protocol recognizes it as representing the committee". * **Proposer** - the [validator](#dfn-validator) that creates a beacon chain block * **Attester** - a [validator](#dfn-validator) that is part of a committee that needs to sign off on a beacon chain block while simultaneously creating a link (crosslink) to a recent shard block on a particular shard chain. @@ -171,7 +171,7 @@ Code snippets appearing in `this style` are to be interpreted as Python code. Be | `EJECTION_BALANCE` | `2**4 * 1e9` (= 16,000,000,000) | Gwei | | `MAX_BALANCE_CHURN_QUOTIENT` | `2**5` (= 32) | - | | `BEACON_CHAIN_SHARD_NUMBER` | `2**64 - 1` | - | -| `MAX_CASPER_VOTES` | `2**10` (= 1,024) | votes | +| `MAX_INDICES_PER_SLASHABLE_VOTE` | `2**10` (= 1,024) | votes | | `MAX_WITHDRAWALS_PER_EPOCH` | `2**2` (= 4) | withdrawals | * For the safety of crosslinks `TARGET_COMMITTEE_SIZE` exceeds [the recommended minimum committee size of 111](https://vitalik.ca/files/Ithaca201807_Sharding.pdf); with sufficient active validators (at least `EPOCH_LENGTH * TARGET_COMMITTEE_SIZE`), the shuffling algorithm ensures committee sizes at least `TARGET_COMMITTEE_SIZE`. (Unbiasable randomness with a Verifiable Delay Function (VDF) will improve committee robustness and lower the safe minimum committee size.) @@ -1163,7 +1163,7 @@ def get_domain(fork: Fork, ```python def verify_slashable_vote_data(state: BeaconState, vote_data: SlashableVoteData) -> bool: - if len(vote_data.custody_bit_0_indices) + len(vote_data.custody_bit_1_indices) > MAX_CASPER_VOTES: + if len(vote_data.custody_bit_0_indices) + len(vote_data.custody_bit_1_indices) > MAX_INDICES_PER_SLASHABLE_VOTE: return False return bls_verify_multiple( From b2855f9be44fea6610ce0c708b1778b9dfb39c14 Mon Sep 17 00:00:00 2001 From: Justin Date: Mon, 28 Jan 2019 21:13:25 +0000 Subject: [PATCH 64/70] Stricter aggregation_bitfield validation Make sure that there's at least one vote in attestations (`bls_verify_multiple` can return `True` with zero votes) --- specs/core/0_beacon-chain.md | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 910ebd378..56b5813f4 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1604,8 +1604,9 @@ For each `attestation` in `block.body.attestations`: * Verify that either `attestation.data.latest_crosslink_root` or `attestation.data.shard_block_root` equals `state.latest_crosslinks[shard].shard_block_root`. * Verify bitfields and aggregate signature: -```python +```python assert attestation.custody_bitfield == b'\x00' * len(attestation.custody_bitfield) # [TO BE REMOVED IN PHASE 1] + assert attestation.aggregation_bitfield != b'\x00' * len(attestation.aggregation_bitfield) for i in range(len(crosslink_committee)): if get_bitfield_bit(attestation.aggregation_bitfield) == 0b0: From 3068e6483d0ffcc718c74d1dadb591c8564ae1a9 Mon Sep 17 00:00:00 2001 From: Justin Date: Mon, 28 Jan 2019 21:13:58 +0000 Subject: [PATCH 65/70] Update 0_beacon-chain.md --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 56b5813f4..9990c5d73 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1604,7 +1604,7 @@ For each `attestation` in `block.body.attestations`: * Verify that either `attestation.data.latest_crosslink_root` or `attestation.data.shard_block_root` equals `state.latest_crosslinks[shard].shard_block_root`. * Verify bitfields and aggregate signature: -```python +```python assert attestation.custody_bitfield == b'\x00' * len(attestation.custody_bitfield) # [TO BE REMOVED IN PHASE 1] assert attestation.aggregation_bitfield != b'\x00' * len(attestation.aggregation_bitfield) From bb0619986ccc8d0635dda445beed90b3315c4a29 Mon Sep 17 00:00:00 2001 From: vbuterin Date: Mon, 28 Jan 2019 16:20:04 -0600 Subject: [PATCH 66/70] Change -> update As per #358 --- specs/core/0_beacon-chain.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 8c9d8a846..a6e9f49ee 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1919,8 +1919,8 @@ and perform the following updates: If a validator registry update does _not_ happen do the following: -* Let `epochs_since_last_registry_change = current_epoch - state.validator_registry_update_epoch`. -* If `epochs_since_last_registry_change` is an exact power of 2: +* Let `epochs_since_last_registry_update = current_epoch - state.validator_registry_update_epoch`. +* If `epochs_since_last_registry_update` is an exact power of 2: * Set `state.current_calculation_epoch = next_epoch`. * Set `state.current_epoch_seed = generate_seed(state, state.current_calculation_epoch)` * _Note_ that `state.current_epoch_start_shard` is left unchanged. From 30ceb8f439151d5b5d63f163f66dc84c3e36b221 Mon Sep 17 00:00:00 2001 From: hukkinj1 Date: Mon, 28 Jan 2019 14:42:31 -0800 Subject: [PATCH 67/70] Removed a trailing space (#514) --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 9990c5d73..808a4082f 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1627,7 +1627,7 @@ For each `attestation` in `block.body.attestations`: ], signature=attestation.aggregate_signature, domain=get_domain(state.fork, slot_to_epoch(attestation.data.slot), DOMAIN_ATTESTATION), - ) + ) ``` * [TO BE REMOVED IN PHASE 1] Verify that `attestation.data.shard_block_root == ZERO_HASH`. From 7da716b0e9db2ecf54dc5fbb2536a8c9eb2d9630 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Mon, 28 Jan 2019 21:18:22 -0700 Subject: [PATCH 68/70] pr feedback --- specs/core/0_beacon-chain.md | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index a6e9f49ee..4adcacdcc 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1527,11 +1527,11 @@ def lmd_ghost(store: Store, start_state: BeaconState, start_block: BeaconBlock) ## Beacon chain state transition function -We now define the state transition function. This is a parent to child block transition. At a high level the state transition is made up of three parts: +We now define the state transition function. At a high level the state transition is made up of three parts: -1. The per-slot transitions, which happens every slot. +1. The per-slot transitions, which happens at the start of every slot. 2. The per-block transitions, which happens at every block. -3. The per-epoch transitions, which happens at every epoch boundary (i.e. `(state.slot + 1) % EPOCH_LENGTH == 0`). +3. The per-epoch transitions, which happens at the end of the last slot of every epoch (i.e. `(state.slot + 1) % EPOCH_LENGTH == 0`). The per-slot transitions focus on the slot counter and block roots records updates; the per-block transitions generally focus on verifying aggregate signatures and saving temporary records relating to the per-block activity in the `BeaconState`; the per-epoch transitions focus on the [validator](#dfn-validator) registry, including adjusting balances and activating and exiting [validators](#dfn-validator), as well as processing crosslinks and managing block justification/finalization. From cbb1571a90dce4244946f5eff5d99c7a08091532 Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Mon, 28 Jan 2019 21:25:59 -0700 Subject: [PATCH 69/70] remove last ref to casper --- specs/core/0_beacon-chain.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 4adcacdcc..a82985b37 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -1599,8 +1599,8 @@ Verify that `len(block.body.attester_slashings) <= MAX_ATTESTER_SLASHINGS`. For each `attester_slashing` in `block.body.attester_slashings`: -* Let `slashable_vote_1 = casper_slashing.slashable_vote_1`. -* Let `slashable_vote_2 = casper_slashing.slashable_vote_2`. +* Let `slashable_vote_1 = attester_slashing.slashable_vote_1`. +* Let `slashable_vote_2 = attester_slashing.slashable_vote_2`. * Let `intersection = [x for x in slashable_vote_1.validator_indices if x in slashable_vote_2.validator_indices]`. * Verify that `len(intersection) >= 1`. * Verify that `slashable_vote_1.data != slashable_vote_2.data`. From 6a3b229cb23cec8003e2b88177d9ec2c6cf19f0f Mon Sep 17 00:00:00 2001 From: Danny Ryan Date: Mon, 28 Jan 2019 21:32:36 -0700 Subject: [PATCH 70/70] minor formatting issue --- specs/core/0_beacon-chain.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index a82985b37..f166c0d7b 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -88,7 +88,7 @@ - [`bls_aggregate_pubkeys`](#bls_aggregate_pubkeys) - [`validate_proof_of_possession`](#validate_proof_of_possession) - [`process_deposit`](#process_deposit) - - [`Routines for updating validator status`](#routines-for-updating-validator-status) + - [Routines for updating validator status](#routines-for-updating-validator-status) - [`activate_validator`](#activate_validator) - [`initiate_validator_exit`](#initiate_validator_exit) - [`exit_validator`](#exit_validator)