update shard blob and headers types, implement shard blob slashings, update shard gossip validation
This commit is contained in:
protolambda
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@ -18,6 +18,8 @@ MAX_SHARDS: 1024
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INITIAL_ACTIVE_SHARDS: 64
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# 2**3 (= 8)
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GASPRICE_ADJUSTMENT_COEFFICIENT: 8
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# 2**6 (= 64)
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MAX_SHARD_PROPOSER_SLASHINGS: 64
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# Shard block configs
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# ---------------------------------------------------------------
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@ -41,5 +43,5 @@ SHARD_COMMITTEE_PERIOD: 256
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# Signature domains
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# ---------------------------------------------------------------
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DOMAIN_SHARD_PROPOSAL: 0x80000000
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DOMAIN_SHARD_PROPOSER: 0x80000000
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DOMAIN_SHARD_COMMITTEE: 0x81000000
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@ -18,6 +18,8 @@ MAX_SHARDS: 8
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INITIAL_ACTIVE_SHARDS: 2
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# 2**3 (= 8)
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GASPRICE_ADJUSTMENT_COEFFICIENT: 8
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# [customized] reduced for testing
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MAX_SHARD_PROPOSER_SLASHINGS: 8
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# Shard block configs
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# ---------------------------------------------------------------
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@ -41,6 +43,5 @@ SHARD_COMMITTEE_PERIOD: 256
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# Signature domains
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# ---------------------------------------------------------------
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DOMAIN_SHARD_PROPOSAL: 0x80000000
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DOMAIN_SHARD_PROPOSER: 0x80000000
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DOMAIN_SHARD_COMMITTEE: 0x81000000
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DOMAIN_LIGHT_CLIENT: 0x82000000
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@ -24,9 +24,13 @@
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- [`BeaconState`](#beaconstate)
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- [New containers](#new-containers)
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- [`DataCommitment`](#datacommitment)
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- [`ShardHeader`](#shardheader)
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- [`SignedShardHeader`](#signedshardheader)
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- [`ShardBlobBodySummary`](#shardblobbodysummary)
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- [`ShardBlobHeader`](#shardblobheader)
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- [`SignedShardBlobHeader`](#signedshardblobheader)
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- [`PendingShardHeader`](#pendingshardheader)
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- [`ShardBlobReference`](#shardblobreference)
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- [`SignedShardBlobReference`](#signedshardblobreference)
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- [`ShardProposerSlashing`](#shardproposerslashing)
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- [Helper functions](#helper-functions)
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- [Misc](#misc-1)
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- [`next_power_of_two`](#next_power_of_two)
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@ -48,6 +52,7 @@
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- [Updated `process_attestation`](#updated-process_attestation)
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- [`update_pending_votes`](#update_pending_votes)
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- [`process_shard_header`](#process_shard_header)
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- [Shard Proposer slashings](#shard-proposer-slashings)
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- [Epoch transition](#epoch-transition)
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- [Pending headers](#pending-headers)
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- [Shard epoch increment](#shard-epoch-increment)
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@ -94,6 +99,7 @@ The following values are (non-configurable) constants used throughout the specif
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| `INITIAL_ACTIVE_SHARDS` | `uint64(2**6)` (= 64) | Initial shard count |
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| `GASPRICE_ADJUSTMENT_COEFFICIENT` | `uint64(2**3)` (= 8) | Gasprice may decrease/increase by at most exp(1 / this value) *per epoch* |
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| `MAX_SHARD_HEADERS_PER_SHARD` | `4` | |
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| `MAX_SHARD_PROPOSER_SLASHINGS` | `2**6` (= 64) | Maximum amount of shard proposer slashing operations per block |
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### Shard block configs
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@ -127,7 +133,7 @@ The following values are (non-configurable) constants used throughout the specif
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| Name | Value |
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| - | - |
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| `DOMAIN_SHARD_HEADER` | `DomainType('0x80000000')` |
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| `DOMAIN_SHARD_PROPOSER` | `DomainType('0x80000000')` |
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| `DOMAIN_SHARD_COMMITTEE` | `DomainType('0x81000000')` |
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## Updated containers
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@ -153,7 +159,8 @@ class AttestationData(Container):
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```python
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class BeaconBlockBody(merge.BeaconBlockBody): # [extends The Merge block body]
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shard_headers: List[SignedShardHeader, MAX_SHARDS * MAX_SHARD_HEADERS_PER_SHARD]
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shard_proposer_slashings: List[ShardProposerSlashing, MAX_SHARD_PROPOSER_SLASHINGS]
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shard_headers: List[SignedShardBlobHeader, MAX_SHARDS * MAX_SHARD_HEADERS_PER_SHARD]
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```
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### `BeaconState`
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@ -186,26 +193,35 @@ class DataCommitment(Container):
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length: uint64
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```
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### `ShardHeader`
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### `ShardBlobBodySummary`
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```python
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class ShardHeader(Container):
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# Slot and shard that this header is intended for
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slot: Slot
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shard: Shard
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class ShardBlobBodySummary(Container):
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# The actual data commitment
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commitment: DataCommitment
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# Proof that the degree < commitment.length
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degree_proof: BLSCommitment
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# Hash-tree-root as summary of the data field
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data_root: Root
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```
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TODO: add shard-proposer-index to shard headers, similar to optimization done with beacon-blocks.
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### `SignedShardHeader`
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### `ShardBlobHeader`
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```python
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class SignedShardHeader(Container):
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message: ShardHeader
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class ShardBlobHeader(Container):
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# Slot and shard that this header is intended for
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slot: Slot
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shard: Shard
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body_summary: ShardBlobBodySummary
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# Proposer of the shard-blob
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proposer_index: ValidatorIndex
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```
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### `SignedShardBlobHeader`
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```python
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class SignedShardBlobHeader(Container):
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message: ShardBlobHeader
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signature: BLSSignature
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```
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@ -226,6 +242,35 @@ class PendingShardHeader(Container):
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confirmed: bool
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```
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### `ShardBlobReference`
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```python
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class ShardBlobReference(Container):
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# Slot and shard that this header is intended for
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slot: Slot
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shard: Shard
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# Hash-tree-root of commitment data
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body_root: Root
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# Proposer of the shard-blob
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proposer_index: ValidatorIndex
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```
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### `SignedShardBlobReference`
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```python
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class SignedShardBlobHeader(Container):
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message: ShardBlobReference
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signature: BLSSignature
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```
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### `ShardProposerSlashing`
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```python
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class ShardProposerSlashing(Container):
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signed_header_1: SignedShardBlobReference
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signed_header_2: SignedShardBlobReference
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```
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## Helper functions
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### Misc
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@ -435,6 +480,8 @@ def process_operations(state: BeaconState, body: BeaconBlockBody) -> None:
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for_ops(body.proposer_slashings, process_proposer_slashing)
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for_ops(body.attester_slashings, process_attester_slashing)
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# New shard proposer slashing processing
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for_ops(body.shard_proposer_slashings, process_shard_proposer_slashing)
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# Limit is dynamic based on active shard count
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assert len(body.shard_headers) <= MAX_SHARD_HEADERS_PER_SHARD * get_active_shard_count(state, get_current_epoch(state))
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for_ops(body.shard_headers, process_shard_header)
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@ -499,30 +546,36 @@ def update_pending_votes(state: BeaconState, attestation: Attestation) -> None:
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```python
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def process_shard_header(state: BeaconState,
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signed_header: SignedShardHeader) -> None:
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signed_header: SignedShardBlobHeader) -> None:
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header = signed_header.message
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header_root = hash_tree_root(header)
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assert compute_epoch_at_slot(header.slot) in [get_previous_epoch(state), get_current_epoch(state)]
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header_epoch = compute_epoch_at_slot(header.slot)
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# Verify that the header is within the processing time window
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assert header_epoch in [get_previous_epoch(state), get_current_epoch(state)]
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# Verify that the shard is active
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assert header.shard < get_active_shard_count(state, header_epoch)
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# Verify proposer
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assert header.proposer_index == get_shard_proposer_index(state, header.slot, header.shard)
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# Verify signature
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signer_index = get_shard_proposer_index(state, header.slot, header.shard)
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signing_root = compute_signing_root(header, get_domain(state, DOMAIN_SHARD_HEADER))
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assert bls.Verify(state.validators[signer_index].pubkey, signing_root, signed_header.signature)
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# Verify the length by verifying the degree.
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if header.commitment.length == 0:
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assert header.degree_proof == G1_SETUP[0]
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body_summary = header.body_summary
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if body_summary.commitment.length == 0:
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assert body_summary.degree_proof == G1_SETUP[0]
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assert (
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bls.Pairing(header.degree_proof, G2_SETUP[0])
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== bls.Pairing(header.commitment.point, G2_SETUP[-header.commitment.length]))
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bls.Pairing(body_summary.degree_proof, G2_SETUP[0])
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== bls.Pairing(body_summary.commitment.point, G2_SETUP[-body_summary.commitment.length]))
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)
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# Get the correct pending header list
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if compute_epoch_at_slot(header.slot) == get_current_epoch(state):
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if header_epoch == get_current_epoch(state):
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pending_headers = state.current_epoch_pending_shard_headers
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else:
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pending_headers = state.previous_epoch_pending_shard_headers
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header_root = hash_tree_root(header)
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# Check that this header is not yet in the pending list
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assert header_root not in [pending_header.root for pending_header in pending_headers]
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@ -532,7 +585,7 @@ def process_shard_header(state: BeaconState,
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pending_headers.append(PendingShardHeader(
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slot=header.slot,
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shard=header.shard,
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commitment=header.commitment,
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commitment=body_summary.commitment,
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root=header_root,
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votes=Bitlist[MAX_VALIDATORS_PER_COMMITTEE]([0] * committee_length),
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confirmed=False,
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@ -544,6 +597,33 @@ the length proof is the commitment to the polynomial `B(X) * X**(MAX_DEGREE + 1
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where `MAX_DEGREE` is the maximum power of `s` available in the setup, which is `MAX_DEGREE = len(G2_SETUP) - 1`.
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The goal is to ensure that a proof can only be constructed if `deg(B) < l` (there are not hidden higher-order terms in the polynomial, which would thwart reconstruction).
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##### Shard Proposer slashings
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```python
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def process_shard_proposer_slashing(state: BeaconState, proposer_slashing: ShardProposerSlashing) -> None:
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header_1 = proposer_slashing.signed_header_1.message
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header_2 = proposer_slashing.signed_header_2.message
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# Verify header slots match
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assert header_1.slot == header_2.slot
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# Verify header shards match
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assert header_1.shard == header_2.shard
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# Verify header proposer indices match
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assert header_1.proposer_index == header_2.proposer_index
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# Verify the headers are different (i.e. different body)
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assert header_1 != header_2
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# Verify the proposer is slashable
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proposer = state.validators[header_1.proposer_index]
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assert is_slashable_validator(proposer, get_current_epoch(state))
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# Verify signatures
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for signed_header in (proposer_slashing.signed_header_1, proposer_slashing.signed_header_2):
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domain = get_domain(state, DOMAIN_SHARD_PROPOSER, compute_epoch_at_slot(signed_header.message.slot))
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signing_root = compute_signing_root(signed_header.message, domain)
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assert bls.Verify(proposer.pubkey, signing_root, signed_header.signature)
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slash_validator(state, header_1.proposer_index)
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```
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### Epoch transition
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This epoch transition overrides the Merge epoch transition:
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@ -10,12 +10,14 @@
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- [Introduction](#introduction)
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- [New containers](#new-containers)
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- [ShardBlobBody](#shardblobbody)
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- [ShardBlob](#shardblob)
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- [SignedShardBlob](#signedshardblob)
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- [Gossip domain](#gossip-domain)
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- [Topics and messages](#topics-and-messages)
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- [Shard blobs: `shard_blob_{shard}`](#shard-blobs-shard_blob_shard)
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- [Shard header: `shard_header`](#shard-header-shard_header)
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- [Shard proposer slashing: `shard_proposer_slashing`](#shard-proposer-slashing-shard_proposer_slashing)
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<!-- END doctoc generated TOC please keep comment here to allow auto update -->
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<!-- /TOC -->
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@ -29,30 +31,39 @@ The adjustments and additions for Shards are outlined in this document.
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## New containers
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### ShardBlob
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Network-only.
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### ShardBlobBody
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```python
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class ShardBlob(Container):
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# Slot and shard that this blob is intended for
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slot: Slot
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shard: Shard
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# The actual data. Represented in header as data commitment and degree proof
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class ShardBlobBody(Container):
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# The actual data commitment
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commitment: DataCommitment
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# Proof that the degree < commitment.length
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degree_proof: BLSCommitment
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# The actual data. Should match the commitment and degree proof.
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data: List[BLSPoint, POINTS_PER_SAMPLE * MAX_SAMPLES_PER_BLOCK]
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```
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Note that the hash-tree-root of the `ShardBlob` does not match the `ShardHeader`,
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since the blob deals with full data, whereas the header includes the KZG commitment and degree proof instead.
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The user MUST always verify the commitments in the `body` are valid for the `data` in the `body`.
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### ShardBlob
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```python
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class ShardBlob(Container):
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# Slot and shard that this header is intended for
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slot: Slot
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shard: Shard
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body: ShardBlobBody
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# Proposer of the shard-blob
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proposer_index: ValidatorIndex
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```
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This is the expanded form of the `ShardBlobHeader` type.
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### SignedShardBlob
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Network-only.
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```python
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class SignedShardBlob(Container):
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message: ShardBlob
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# The signature, the message is the commitment on the blob
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signature: BLSSignature
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```
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@ -66,6 +77,7 @@ Following the same scheme as the [Phase0 gossip topics](../phase0/p2p-interface.
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|----------------------------------|---------------------------|
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| `shard_blob_{shard}` | `SignedShardBlob` |
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| `shard_header` | `SignedShardHeader` |
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| `shard_proposer_slashing` | `ShardProposerSlashing` |
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The [DAS network specification](./das-p2p.md) defines additional topics.
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@ -73,22 +85,49 @@ The [DAS network specification](./das-p2p.md) defines additional topics.
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Shard block data, in the form of a `SignedShardBlob` is published to the `shard_blob_{shard}` subnets.
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The following validations MUST pass before forwarding the `signed_blob` (with inner `blob`) on the horizontal subnet or creating samples for it.
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The following validations MUST pass before forwarding the `signed_blob` (with inner `message` as `blob`) on the horizontal subnet or creating samples for it.
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- _[REJECT]_ `blob.shard` MUST match the topic `{shard}` parameter. (And thus within valid shard index range)
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- _[IGNORE]_ The `blob` is not from a future slot (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) --
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i.e. validate that `blob.slot <= current_slot`
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(a client MAY queue future blobs for processing at the appropriate slot).
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- _[IGNORE]_ The blob is the first blob with valid signature received for the proposer for the `(slot, shard)` combination.
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- _[IGNORE]_ The `blob` is new enough to be still be processed --
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i.e. validate that `compute_epoch_at_slot(blob.slot) >= get_previous_epoch(state)`
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- _[IGNORE]_ The blob is the first blob with valid signature received for the `(blob.proposer_index, blob.slot, blob.shard)` combination.
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- _[REJECT]_ As already limited by the SSZ list-limit, it is important the blob is well-formatted and not too large.
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- _[REJECT]_ The `blob.data` MUST NOT contain any point `p >= MODULUS`. Although it is a `uint256`, not the full 256 bit range is valid.
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- _[REJECT]_ The proposer signature, `signed_blob.signature`, is valid with respect to the `proposer_index` pubkey, signed over the SSZ output of `commit_to_data(blob.data)`.
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- _[REJECT]_ The blob is proposed by the expected `proposer_index` for the blob's slot.
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- _[REJECT]_ The proposer signature, `signed_blob.signature`, is valid with respect to the `proposer_index` pubkey.
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- _[REJECT]_ The blob is proposed by the expected `proposer_index` for the blob's slot
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in the context of the current shuffling (defined by `parent_root`/`slot`).
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If the `proposer_index` cannot immediately be verified against the expected shuffling,
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the block MAY be queued for later processing while proposers for the blob's branch are calculated --
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in such a case _do not_ `REJECT`, instead `IGNORE` this message.
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TODO: make double blob proposals slashable?
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#### Shard header: `shard_header`
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Shard header data, in the form of a `SignedShardHeader` is published to the global `shard_header` subnet.
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Shard header data, in the form of a `SignedShardBlobHeader` is published to the global `shard_header` subnet.
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TODO: validation conditions.
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The following validations MUST pass before forwarding the `signed_shard_header` (with inner `message` as `header`) on the network.
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- _[IGNORE]_ The `header` is not from a future slot (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) --
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i.e. validate that `header.slot <= current_slot`
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(a client MAY queue future headers for processing at the appropriate slot).
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- _[IGNORE]_ The `header` is new enough to be still be processed --
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i.e. validate that `compute_epoch_at_slot(header.slot) >= get_previous_epoch(state)`
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- _[IGNORE]_ The header is the first header with valid signature received for the `(header.proposer_index, header.slot, header.shard)` combination.
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- _[REJECT]_ The proposer signature, `signed_shard_header.signature`, is valid with respect to the `proposer_index` pubkey.
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- _[REJECT]_ The header is proposed by the expected `proposer_index` for the block's slot
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in the context of the current shuffling (defined by `parent_root`/`slot`).
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If the `proposer_index` cannot immediately be verified against the expected shuffling,
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the block MAY be queued for later processing while proposers for the block's branch are calculated --
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in such a case _do not_ `REJECT`, instead `IGNORE` this message.
|
||||
|
||||
|
||||
#### Shard proposer slashing: `shard_proposer_slashing`
|
||||
|
||||
Shard proposer slashings, in the form of `ShardProposerSlashing`, are published to the global `shard_proposer_slashing` topic.
|
||||
|
||||
The following validations MUST pass before forwarding the `shard_proposer_slashing` on to the network.
|
||||
- _[IGNORE]_ The shard proposer slashing is the first valid shard proposer slashing received
|
||||
for the proposer with index `proposer_slashing.signed_header_1.message.proposer_index`.
|
||||
The `slot` and `shard` are ignored, there are no per-shard slashings.
|
||||
- _[REJECT]_ All of the conditions within `process_shard_proposer_slashing` pass validation.
|
||||
|
|
|
|||
Loading…
Reference in New Issue