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Update the endianess of the polynomial commitments to be big endian

This commit is contained in:
gajinder 2023-05-12 21:44:43 +05:30
parent f7352d18cf
commit 5b983f4097
1 changed files with 9 additions and 8 deletions
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17
specs/deneb/polynomial-commitments.md
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@ -77,6 +77,7 @@ Public functions MUST accept raw bytes as input and perform the required cryptog
| `BYTES_PER_FIELD_ELEMENT` | `uint64(32)` | Bytes used to encode a BLS scalar field element |
| `BYTES_PER_BLOB` | `uint64(BYTES_PER_FIELD_ELEMENT * FIELD_ELEMENTS_PER_BLOB)` | The number of bytes in a blob |
| `G1_POINT_AT_INFINITY` | `Bytes48(b'\xc0' + b'\x00' * 47)` | Serialized form of the point at infinity on the G1 group |
| `KZG_ENDIANNESS` | `'big'` | The endianess of the field elements including blobs |
## Preset
@ -161,7 +162,7 @@ def hash_to_bls_field(data: bytes) -> BLSFieldElement:
The output is not uniform over the BLS field.
"""
hashed_data = hash(data)
return BLSFieldElement(int.from_bytes(hashed_data, ENDIANNESS) % BLS_MODULUS)
return BLSFieldElement(int.from_bytes(hashed_data, KZG_ENDIANNESS) % BLS_MODULUS)
```
#### `bytes_to_bls_field`
@ -172,7 +173,7 @@ def bytes_to_bls_field(b: Bytes32) -> BLSFieldElement:
Convert untrusted bytes to a trusted and validated BLS scalar field element.
This function does not accept inputs greater than the BLS modulus.
"""
field_element = int.from_bytes(b, ENDIANNESS)
field_element = int.from_bytes(b, KZG_ENDIANNESS)
assert field_element < BLS_MODULUS
return BLSFieldElement(field_element)
```
@ -237,7 +238,7 @@ def compute_challenge(blob: Blob,
"""
# Append the degree of the polynomial as a domain separator
degree_poly = int.to_bytes(FIELD_ELEMENTS_PER_BLOB, 16, ENDIANNESS)
degree_poly = int.to_bytes(FIELD_ELEMENTS_PER_BLOB, 16, KZG_ENDIANNESS)
data = FIAT_SHAMIR_PROTOCOL_DOMAIN + degree_poly
data += blob
@ -406,15 +407,15 @@ def verify_kzg_proof_batch(commitments: Sequence[KZGCommitment],
# Compute a random challenge. Note that it does not have to be computed from a hash,
# r just has to be random.
degree_poly = int.to_bytes(FIELD_ELEMENTS_PER_BLOB, 8, ENDIANNESS)
num_commitments = int.to_bytes(len(commitments), 8, ENDIANNESS)
degree_poly = int.to_bytes(FIELD_ELEMENTS_PER_BLOB, 8, KZG_ENDIANNESS)
num_commitments = int.to_bytes(len(commitments), 8, KZG_ENDIANNESS)
data = RANDOM_CHALLENGE_KZG_BATCH_DOMAIN + degree_poly + num_commitments
# Append all inputs to the transcript before we hash
for commitment, z, y, proof in zip(commitments, zs, ys, proofs):
data += commitment \
+ int.to_bytes(z, BYTES_PER_FIELD_ELEMENT, ENDIANNESS) \
+ int.to_bytes(y, BYTES_PER_FIELD_ELEMENT, ENDIANNESS) \
+ int.to_bytes(z, BYTES_PER_FIELD_ELEMENT, KZG_ENDIANNESS) \
+ int.to_bytes(y, BYTES_PER_FIELD_ELEMENT, KZG_ENDIANNESS) \
+ proof
r = hash_to_bls_field(data)
@ -451,7 +452,7 @@ def compute_kzg_proof(blob: Blob, z_bytes: Bytes32) -> Tuple[KZGProof, Bytes32]:
assert len(z_bytes) == BYTES_PER_FIELD_ELEMENT
polynomial = blob_to_polynomial(blob)
proof, y = compute_kzg_proof_impl(polynomial, bytes_to_bls_field(z_bytes))
return proof, y.to_bytes(BYTES_PER_FIELD_ELEMENT, ENDIANNESS)
return proof, y.to_bytes(BYTES_PER_FIELD_ELEMENT, KZG_ENDIANNESS)
```
#### `compute_quotient_eval_within_domain`