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Added domain separation

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specs/core/0_beacon-chain.md
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@ -90,6 +90,15 @@ The primary source of load on the beacon chain are "attestations". Attestations
| `ENTRY` | `0` | | `ENTRY` | `0` |
| `EXIT` | `1` | | `EXIT` | `1` |
**Domains for BLS signatures**
| Name | Value |
| - | :-: |
| `DOMAIN_DEPOSIT` | `0` |
| `DOMAIN_ATTESTATION` | `1` |
| `DOMAIN_PROPOSAL` | `2` |
| `DOMAIN_LOGOUT` | `3` |
### PoW chain registration contract ### PoW chain registration contract
The initial deployment phases of Ethereum 2.0 are implemented without consensus changes to the PoW chain. A registration contract is added to the PoW chain to deposit ETH. This contract has a `registration` function which takes as arguments `pubkey`, `withdrawal_shard`, `withdrawal_address`, `randao_commitment` as defined in a `ValidatorRecord` below. A BLS `proof_of_possession` of types `bytes` is given as a final argument. The initial deployment phases of Ethereum 2.0 are implemented without consensus changes to the PoW chain. A registration contract is added to the PoW chain to deposit ETH. This contract has a `registration` function which takes as arguments `pubkey`, `withdrawal_shard`, `withdrawal_address`, `randao_commitment` as defined in a `ValidatorRecord` below. A BLS `proof_of_possession` of types `bytes` is given as a final argument.
@ -152,8 +161,6 @@ An `AttestationSignedData` has the following fields:
```python ```python
{ {
# Fork version
'fork_version': 'uint64',
# Slot number # Slot number
'slot': 'uint64', 'slot': 'uint64',
# Shard number # Shard number
@ -652,7 +659,7 @@ The `add_validator` routine is defined below.
This routine should be run for every validator that is inducted as part of a log created on the PoW chain [TODO: explain where to check for these logs]. The status of the validators added after genesis is `PENDING_ACTIVATION`. These logs should be processed in the order in which they are emitted by the PoW chain. This routine should be run for every validator that is inducted as part of a log created on the PoW chain [TODO: explain where to check for these logs]. The status of the validators added after genesis is `PENDING_ACTIVATION`. These logs should be processed in the order in which they are emitted by the PoW chain.
First, a helper function: First, some helper functions:
```python ```python
def min_empty_validator(validators: List[ValidatorRecord], current_slot: int): def min_empty_validator(validators: List[ValidatorRecord], current_slot: int):
@ -662,10 +669,15 @@ def min_empty_validator(validators: List[ValidatorRecord], current_slot: int):
return None return None
``` ```
```python
def get_fork_version(state: State, slot: uint64):
return state.pre_fork_version if slot < state.fork_slot_number else state.post_fork_version
```
Now, to add a validator: Now, to add a validator:
```python ```python
def add_validator(validators: List[ValidatorRecord], def add_validator(state: State,
pubkey: int, pubkey: int,
proof_of_possession: bytes, proof_of_possession: bytes,
withdrawal_shard: int, withdrawal_shard: int,
@ -678,7 +690,8 @@ def add_validator(validators: List[ValidatorRecord],
signed_message = as_bytes32(pubkey) + as_bytes2(withdrawal_shard) + withdrawal_address + randao_commitment signed_message = as_bytes32(pubkey) + as_bytes2(withdrawal_shard) + withdrawal_address + randao_commitment
assert BLSVerify(pub=pubkey, assert BLSVerify(pub=pubkey,
msg=hash(signed_message), msg=hash(signed_message),
sig=proof_of_possession) sig=proof_of_possession,
domain=get_fork_version(state, current_slot) * 2**32 + DOMAIN_DEPOSIT)
# Pubkey uniqueness # Pubkey uniqueness
assert pubkey not in [v.pubkey for v in validators] assert pubkey not in [v.pubkey for v in validators]
rec = ValidatorRecord( rec = ValidatorRecord(
@ -815,9 +828,9 @@ For each one of these attestations:
* Compute `parent_hashes` = `[get_block_hash(state, block, slot - CYCLE_LENGTH + i) for i in range(1, CYCLE_LENGTH - len(oblique_parent_hashes) + 1)] + oblique_parent_hashes` (eg, if `CYCLE_LENGTH = 4`, `slot = 5`, the actual block hashes starting from slot 0 are `Z A B C D E F G H I J`, and `oblique_parent_hashes = [D', E']` then `parent_hashes = [B, C, D' E']`). Note that when *creating* an attestation for a block, the hash of that block itself won't yet be in the `state`, so you would need to add it explicitly. * Compute `parent_hashes` = `[get_block_hash(state, block, slot - CYCLE_LENGTH + i) for i in range(1, CYCLE_LENGTH - len(oblique_parent_hashes) + 1)] + oblique_parent_hashes` (eg, if `CYCLE_LENGTH = 4`, `slot = 5`, the actual block hashes starting from slot 0 are `Z A B C D E F G H I J`, and `oblique_parent_hashes = [D', E']` then `parent_hashes = [B, C, D' E']`). Note that when *creating* an attestation for a block, the hash of that block itself won't yet be in the `state`, so you would need to add it explicitly.
* Let `attestation_indices` be `get_shards_and_committees_for_slot(state, slot)[x]`, choosing `x` so that `attestation_indices.shard` equals the `shard` value provided to find the set of validators that is creating this attestation record. * Let `attestation_indices` be `get_shards_and_committees_for_slot(state, slot)[x]`, choosing `x` so that `attestation_indices.shard` equals the `shard` value provided to find the set of validators that is creating this attestation record.
* Verify that `len(attester_bitfield) == ceil_div8(len(attestation_indices))`, where `ceil_div8 = (x + 7) // 8`. Verify that bits `len(attestation_indices)....` and higher, if present (i.e. `len(attestation_indices)` is not a multiple of 8), are all zero. * Verify that `len(attester_bitfield) == ceil_div8(len(attestation_indices))`, where `ceil_div8 = (x + 7) // 8`. Verify that bits `len(attestation_indices)....` and higher, if present (i.e. `len(attestation_indices)` is not a multiple of 8), are all zero.
* Derive a group public key by adding the public keys of all of the attesters in `attestation_indices` for whom the corresponding bit in `attester_bitfield` (the ith bit is `(attester_bitfield[i // 8] >> (7 - (i %8))) % 2`) equals 1. * Derive a `group_public_key` by adding the public keys of all of the attesters in `attestation_indices` for whom the corresponding bit in `attester_bitfield` (the ith bit is `(attester_bitfield[i // 8] >> (7 - (i %8))) % 2`) equals 1.
* Let `fork_version = pre_fork_version if slot < fork_slot_number else post_fork_version`. * Let `data = AttestationSignedData(slot, shard, parent_hashes, shard_block_hash, last_crosslinked_hash, shard_block_combined_data_root, justified_slot)`
* Verify that `aggregate_sig` verifies using the group pubkey generated and the serialized form of `AttestationSignedData(fork_version, slot, shard, parent_hashes, shard_block_hash, last_crosslinked_hash, shard_block_combined_data_root, justified_slot)` as the message. * Check `BLSVerify(pubkey=group_public_key, msg=data, sig=aggregate_sig, domain=get_fork_version(state, slot) * 2**32 + DOMAIN_ATTESTATION)`
Extend the list of `AttestationRecord` objects in the `state` with those included in the block, ordering the new additions in the same order as they came in the block. Extend the list of `AttestationRecord` objects in the `state` with those included in the block, ordering the new additions in the same order as they came in the block.
@ -843,12 +856,12 @@ For each `SpecialRecord` `obj` in `block.specials`, verify that its `kind` is on
```python ```python
{ {
'validator_index': 'uint64', 'validator_index': 'uint64',
'signature': '[uint256]' 'signature': '[uint384]'
} }
``` ```
Perform the following checks: Perform the following checks:
* Let `fork_version = pre_fork_version if block.slot < fork_slot_number else post_fork_version`. Verify that `BLSVerify(pubkey=validators[data.validator_index].pubkey, msg=hash(LOGOUT_MESSAGE + bytes8(fork_version)), sig=data.signature)` * Verify that `BLSVerify(pubkey=validators[data.validator_index].pubkey, msg=hash(LOGOUT_MESSAGE + bytes8(fork_version)), sig=data.signature, domain=get_fork_version(state, current_slot) * 2**32 + DOMAIN_LOGOUT)`
* Verify that `validators[validator_index].status == ACTIVE`. * Verify that `validators[validator_index].status == ACTIVE`.
Run `exit_validator(data.validator_index, state, penalize=False, current_slot=block.slot)`. Run `exit_validator(data.validator_index, state, penalize=False, current_slot=block.slot)`.
@ -859,16 +872,16 @@ Run `exit_validator(data.validator_index, state, penalize=False, current_slot=bl
{ {
'vote1_aggregate_sig_indices': '[uint24]', 'vote1_aggregate_sig_indices': '[uint24]',
'vote1_data': AttestationSignedData, 'vote1_data': AttestationSignedData,
'vote1_aggregate_sig': '[uint256]', 'vote1_aggregate_sig': '[uint384]',
'vote2_aggregate_sig_indices': '[uint24]', 'vote2_aggregate_sig_indices': '[uint24]',
'vote2_data': AttestationSignedData, 'vote2_data': AttestationSignedData,
'vote2_aggregate_sig': '[uint256]', 'vote2_aggregate_sig': '[uint384]',
} }
``` ```
Perform the following checks: Perform the following checks:
* For each `aggregate_sig`, verify that `BLSVerify(pubkey=aggregate_pubkey([validators[i].pubkey for i in aggregate_sig_indices]), msg=vote_data, sig=aggsig)` passes. * For each `aggregate_sig`, verify that `BLSVerify(pubkey=aggregate_pubkey([validators[i].pubkey for i in aggregate_sig_indices]), msg=vote_data, sig=aggsig, domain=get_fork_version(state, vote_data.slot) * 2**32 + DOMAIN_ATTESTATION)` passes.
* Verify that `vote1_data != vote2_data`. * Verify that `vote1_data != vote2_data`.
* Let `intersection = [x for x in vote1_aggregate_sig_indices if x in vote2_aggregate_sig_indices]`. Verify that `len(intersection) >= 1`. * Let `intersection = [x for x in vote1_aggregate_sig_indices if x in vote2_aggregate_sig_indices]`. Verify that `len(intersection) >= 1`.
* Verify that `vote1_data.justified_slot < vote2_data.justified_slot < vote2_data.slot <= vote1_data.slot`. * Verify that `vote1_data.justified_slot < vote2_data.justified_slot < vote2_data.slot <= vote1_data.slot`.