halo2_axiom/poly/kzg/multiopen/gwc/
prover.rs

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1use super::{construct_intermediate_sets, ChallengeV, Query};
2use crate::arithmetic::{kate_division, powers};
3use crate::helpers::SerdeCurveAffine;
4use crate::poly::commitment::ParamsProver;
5use crate::poly::commitment::Prover;
6use crate::poly::kzg::commitment::{KZGCommitmentScheme, ParamsKZG};
7use crate::poly::query::ProverQuery;
8use crate::poly::{commitment::Blind, Polynomial};
9use crate::transcript::{EncodedChallenge, TranscriptWrite};
10
11use group::Curve;
12use pairing::Engine;
13use rand_core::RngCore;
14use std::fmt::Debug;
15use std::io;
16use std::marker::PhantomData;
17
18/// Concrete KZG prover with GWC variant
19#[derive(Debug)]
20pub struct ProverGWC<'params, E: Engine> {
21    params: &'params ParamsKZG<E>,
22}
23
24/// Create a multi-opening proof
25impl<'params, E: Engine + Debug> Prover<'params, KZGCommitmentScheme<E>> for ProverGWC<'params, E>
26where
27    E::G1Affine: SerdeCurveAffine<ScalarExt = E::Fr, CurveExt = E::G1>,
28    E::G2Affine: SerdeCurveAffine,
29{
30    const QUERY_INSTANCE: bool = false;
31
32    fn new(params: &'params ParamsKZG<E>) -> Self {
33        Self { params }
34    }
35
36    /// Create a multi-opening proof
37    fn create_proof<
38        'com,
39        Ch: EncodedChallenge<E::G1Affine>,
40        T: TranscriptWrite<E::G1Affine, Ch>,
41        R,
42        I,
43    >(
44        &self,
45        _: R,
46        transcript: &mut T,
47        queries: I,
48    ) -> io::Result<()>
49    where
50        I: IntoIterator<Item = ProverQuery<'com, E::G1Affine>> + Clone,
51        R: RngCore,
52    {
53        let v: ChallengeV<_> = transcript.squeeze_challenge_scalar();
54        let commitment_data = construct_intermediate_sets(queries);
55
56        for commitment_at_a_point in commitment_data.iter() {
57            let z = commitment_at_a_point.point;
58            let (poly_batch, eval_batch) = commitment_at_a_point
59                .queries
60                .iter()
61                .zip(powers(*v))
62                .map(|(query, power_of_v)| {
63                    assert_eq!(query.get_point(), z);
64
65                    let poly = query.get_commitment().poly;
66                    let eval = query.get_eval();
67
68                    (poly.clone() * power_of_v, eval * power_of_v)
69                })
70                .reduce(|(poly_acc, eval_acc), (poly, eval)| (poly_acc + &poly, eval_acc + eval))
71                .unwrap();
72
73            let poly_batch = &poly_batch - eval_batch;
74            let witness_poly = Polynomial {
75                values: kate_division(&poly_batch.values, z),
76                _marker: PhantomData,
77            };
78            let w = self
79                .params
80                .commit(&witness_poly, Blind::default())
81                .to_affine();
82
83            transcript.write_point(w)?;
84        }
85        Ok(())
86    }
87}
halo2_axiom/poly/kzg/multiopen/gwc/prover.rs

halo2_axiom/poly/kzg/multiopen/gwc/
prover.rs
