status-im
/
eth2.0-specs
mirror of https://github.com/status-im/eth2.0-specs.git
2
0
Fork 0
Code Issues Projects Releases Wiki Activity

Remove placeholders 

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](a9328157a8 (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
This commit is contained in:
Justin 2019-01-22 20:45:30 +00:00 committed by GitHub
parent 5c2b595c2d
commit 6c824ffee4
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 10 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
specs/core/0_beacon-chain.md
View File

@ -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`.