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Merge pull request #2540 from Nashatyrev/fix/datacommitment-length 

[Sharding] Rename `DataCommitment.length` field to `samples_count` and fix `degree_proof` validation
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Diederik Loerakker 2021-08-11 17:03:30 +02:00 committed by GitHub
parent c404cd144a 68db644ae9
commit dd58c702d1
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1 changed files with 7 additions and 6 deletions
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specs/sharding/beacon-chain.md
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@ -242,7 +242,7 @@ class DataCommitment(Container):
# KZG10 commitment to the data
point: BLSCommitment
# Length of the data in samples
length: uint64
samples_count: uint64
```
### `AttestedDataCommitment`
@ -266,7 +266,7 @@ Unique, signing different bodies as shard proposer for the same `(slot, shard)`
class ShardBlobBody(Container):
# The actual data commitment
commitment: DataCommitment
# Proof that the degree < commitment.length
# Proof that the degree < commitment.samples_count * POINTS_PER_SAMPLE
degree_proof: BLSCommitment
# The actual data. Should match the commitment and degree proof.
data: List[BLSPoint, POINTS_PER_SAMPLE * MAX_SAMPLES_PER_BLOB]
@ -289,7 +289,7 @@ to avoid an extra network roundtrip between proposer and builder, to include the
class ShardBlobBodySummary(Container):
# The actual data commitment
commitment: DataCommitment
# Proof that the degree < commitment.length
# Proof that the degree < commitment.samples_count * POINTS_PER_SAMPLE
degree_proof: BLSCommitment
# Hash-tree-root as summary of the data field
data_root: Root
@ -719,16 +719,17 @@ def process_shard_header(state: BeaconState, signed_header: SignedShardBlobHeade
# Verify the length by verifying the degree.
body_summary = header.body_summary
if body_summary.commitment.length == 0:
points_count = body_summary.commitment.samples_count * POINTS_PER_SAMPLE
if points_count == 0:
assert body_summary.degree_proof == G1_SETUP[0]
assert (
bls.Pairing(body_summary.degree_proof, G2_SETUP[0])
== bls.Pairing(body_summary.commitment.point, G2_SETUP[-body_summary.commitment.length])
== bls.Pairing(body_summary.commitment.point, G2_SETUP[-points_count])
)
# Charge EIP 1559 fee, builder pays for opportunity, and is responsible for later availability,
# or fail to publish at their own expense.
samples = body_summary.commitment.length
samples = body_summary.commitment.samples_count
# TODO: overflows, need bigger int type
max_fee = body_summary.max_fee_per_sample * samples