mirror of
https://github.com/logos-blockchain/logos-blockchain-specs.git
synced 2026-01-07 15:43:07 +00:00
61 lines
2.2 KiB
Python
61 lines
2.2 KiB
Python
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from hashlib import blake2b
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from typing import List, Sequence
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from da.common import Chunk
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from da.kzg_rs.common import BLS_MODULUS
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from eth2spec.eip7594.mainnet import BLSFieldElement, KZGCommitment as Commitment
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from eth2spec.utils import bls
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from da.kzg_rs.poly import Polynomial
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def derive_challenge(row_commitments: List[Commitment]) -> BLSFieldElement:
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"""
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Derive a Fiat–Shamir challenge scalar h from the row commitments:
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h = BLAKE2b-31( DST || bytes(com1) || bytes(com2) || ... )
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"""
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_DST = b"NOMOS_DA_V1"
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h = blake2b(digest_size=31)
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h.update(_DST)
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for com in row_commitments:
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h.update(bytes(com))
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digest31 = h.digest() # 31 bytes
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# pad to 32 bytes for field element conversion
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padded = digest31 + b'\x00'
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return BLSFieldElement.from_bytes(padded)
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def combine_commitments(row_commitments: List[Commitment], h: BLSFieldElement) -> Commitment:
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combined_commitment = bls.bytes48_to_G1(row_commitments[0])
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power = int(h) % BLS_MODULUS
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for commitment in row_commitments[1:]:
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commitment = bls.bytes48_to_G1(commitment)
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combined_commitment = bls.add(combined_commitment, bls.multiply(commitment, power))
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power = (power * int(h)) % BLS_MODULUS
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return bls.G1_to_bytes48(combined_commitment)
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def compute_combined_polynomial(
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polys: Sequence[Polynomial], h: BLSFieldElement
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) -> Polynomial:
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combined_polynomial = polys[0]
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h_int = int(h) # raw integer challenge
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int_pow = 1
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for poly in polys[1:]:
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int_pow = (int_pow * h_int) % BLS_MODULUS
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combined_polynomial = combined_polynomial + Polynomial([int_pow * coeff for coeff in poly], BLS_MODULUS)
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return combined_polynomial
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def compute_combined_evaluation(
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evals: Sequence[Chunk],
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h: BLSFieldElement
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) -> BLSFieldElement:
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combined_eval_int = 0
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power_int = 1
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h_int = int(h) % BLS_MODULUS
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for chunk in evals:
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chunk_int = int.from_bytes(bytes(chunk), byteorder="big")
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combined_eval_int = (combined_eval_int + chunk_int * power_int) % BLS_MODULUS
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power_int = (power_int * h_int) % BLS_MODULUS
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return BLSFieldElement(combined_eval_int)
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