mirror of
https://github.com/arnaucube/hyperplonk.git
synced 2026-01-12 00:51:27 +01:00
polish IOP code base (#24)
This commit is contained in:
@@ -1,12 +1,10 @@
|
||||
//! This module implements the sum check protocol.
|
||||
//! Currently this is a simple wrapper of the sumcheck protocol
|
||||
//! from Arkworks.
|
||||
|
||||
use crate::{
|
||||
errors::PolyIOPErrors,
|
||||
structs::{DomainInfo, IOPProof, IOPProverState, IOPVerifierState, SubClaim},
|
||||
structs::{IOPProof, IOPProverState, IOPVerifierState, SubClaim},
|
||||
transcript::IOPTranscript,
|
||||
virtual_poly::VirtualPolynomial,
|
||||
virtual_poly::{VPAuxInfo, VirtualPolynomial},
|
||||
PolyIOP,
|
||||
};
|
||||
use ark_ff::PrimeField;
|
||||
@@ -18,12 +16,12 @@ mod verifier;
|
||||
/// Trait for doing sum check protocols.
|
||||
pub trait SumCheck<F: PrimeField> {
|
||||
type Proof;
|
||||
type PolyList;
|
||||
type DomainInfo;
|
||||
type VirtualPolynomial;
|
||||
type VPAuxInfo;
|
||||
type SubClaim;
|
||||
type Transcript;
|
||||
|
||||
/// extract sum from the proof
|
||||
/// Extract sum from the proof
|
||||
fn extract_sum(proof: &Self::Proof) -> F;
|
||||
|
||||
/// Initialize the system with a transcript
|
||||
@@ -38,7 +36,7 @@ pub trait SumCheck<F: PrimeField> {
|
||||
///
|
||||
/// The polynomial is represented in the form of a VirtualPolynomial.
|
||||
fn prove(
|
||||
poly: &Self::PolyList,
|
||||
poly: &Self::VirtualPolynomial,
|
||||
transcript: &mut Self::Transcript,
|
||||
) -> Result<Self::Proof, PolyIOPErrors>;
|
||||
|
||||
@@ -46,7 +44,7 @@ pub trait SumCheck<F: PrimeField> {
|
||||
fn verify(
|
||||
sum: F,
|
||||
proof: &Self::Proof,
|
||||
domain_info: &Self::DomainInfo,
|
||||
aux_info: &Self::VPAuxInfo,
|
||||
transcript: &mut Self::Transcript,
|
||||
) -> Result<Self::SubClaim, PolyIOPErrors>;
|
||||
}
|
||||
@@ -56,17 +54,15 @@ pub trait SumCheckProver<F: PrimeField>
|
||||
where
|
||||
Self: Sized,
|
||||
{
|
||||
type PolyList;
|
||||
type VirtualPolynomial;
|
||||
type ProverMessage;
|
||||
|
||||
/// Initialize the prover to argue for the sum of polynomial over
|
||||
/// {0,1}^`num_vars`
|
||||
///
|
||||
/// The polynomial is represented in the form of a VirtualPolynomial.
|
||||
fn prover_init(polynomial: &Self::PolyList) -> Result<Self, PolyIOPErrors>;
|
||||
/// Initialize the prover state to argue for the sum of the input polynomial
|
||||
/// over {0,1}^`num_vars`.
|
||||
fn prover_init(polynomial: &Self::VirtualPolynomial) -> Result<Self, PolyIOPErrors>;
|
||||
|
||||
/// receive message from verifier, generate prover message, and proceed to
|
||||
/// next round
|
||||
/// Receive message from verifier, generate prover message, and proceed to
|
||||
/// next round.
|
||||
///
|
||||
/// Main algorithm used is from section 3.2 of [XZZPS19](https://eprint.iacr.org/2019/317.pdf#subsection.3.2).
|
||||
fn prove_round_and_update_state(
|
||||
@@ -77,31 +73,33 @@ where
|
||||
|
||||
/// Trait for sum check protocol verifier side APIs.
|
||||
pub trait SumCheckVerifier<F: PrimeField> {
|
||||
type DomainInfo;
|
||||
type VPAuxInfo;
|
||||
type ProverMessage;
|
||||
type Challenge;
|
||||
type Transcript;
|
||||
type SubClaim;
|
||||
|
||||
/// initialize the verifier
|
||||
fn verifier_init(index_info: &Self::DomainInfo) -> Self;
|
||||
/// Initialize the verifier's state.
|
||||
fn verifier_init(index_info: &Self::VPAuxInfo) -> Self;
|
||||
|
||||
/// Run verifier at current round, given prover message
|
||||
/// Run verifier for the current round, given a prover message.
|
||||
///
|
||||
/// Normally, this function should perform actual verification. Instead,
|
||||
/// `verify_round` only samples and stores randomness and perform
|
||||
/// verifications altogether in `check_and_generate_subclaim` at
|
||||
/// the last step.
|
||||
/// Note that `verify_round_and_update_state` only samples and stores
|
||||
/// challenges; and update the verifier's state accordingly. The actual
|
||||
/// verifications are deferred (in batch) to `check_and_generate_subclaim`
|
||||
/// at the last step.
|
||||
fn verify_round_and_update_state(
|
||||
&mut self,
|
||||
prover_msg: &Self::ProverMessage,
|
||||
transcript: &mut Self::Transcript,
|
||||
) -> Result<Self::Challenge, PolyIOPErrors>;
|
||||
|
||||
/// verify the sumcheck phase, and generate the subclaim
|
||||
/// This function verifies the deferred checks in the interactive version of
|
||||
/// the protocol; and generate the subclaim. Returns an error if the
|
||||
/// proof failed to verify.
|
||||
///
|
||||
/// If the asserted sum is correct, then the multilinear polynomial
|
||||
/// evaluated at `subclaim.point` is `subclaim.expected_evaluation`.
|
||||
/// evaluated at `subclaim.point` will be `subclaim.expected_evaluation`.
|
||||
/// Otherwise, it is highly unlikely that those two will be equal.
|
||||
/// Larger field size guarantees smaller soundness error.
|
||||
fn check_and_generate_subclaim(
|
||||
@@ -112,15 +110,12 @@ pub trait SumCheckVerifier<F: PrimeField> {
|
||||
|
||||
impl<F: PrimeField> SumCheck<F> for PolyIOP<F> {
|
||||
type Proof = IOPProof<F>;
|
||||
|
||||
type PolyList = VirtualPolynomial<F>;
|
||||
|
||||
type DomainInfo = DomainInfo<F>;
|
||||
|
||||
type VirtualPolynomial = VirtualPolynomial<F>;
|
||||
type VPAuxInfo = VPAuxInfo<F>;
|
||||
type SubClaim = SubClaim<F>;
|
||||
|
||||
type Transcript = IOPTranscript<F>;
|
||||
|
||||
/// Extract sum from the proof
|
||||
fn extract_sum(proof: &Self::Proof) -> F {
|
||||
let start = start_timer!(|| "extract sum");
|
||||
let res = proof.proofs[0].evaluations[0] + proof.proofs[0].evaluations[1];
|
||||
@@ -145,17 +140,17 @@ impl<F: PrimeField> SumCheck<F> for PolyIOP<F> {
|
||||
///
|
||||
/// The polynomial is represented in the form of a VirtualPolynomial.
|
||||
fn prove(
|
||||
poly: &Self::PolyList,
|
||||
poly: &Self::VirtualPolynomial,
|
||||
transcript: &mut Self::Transcript,
|
||||
) -> Result<Self::Proof, PolyIOPErrors> {
|
||||
let start = start_timer!(|| "sum check prove");
|
||||
|
||||
transcript.append_domain_info(&poly.domain_info)?;
|
||||
transcript.append_aux_info(&poly.aux_info)?;
|
||||
|
||||
let mut prover_state = IOPProverState::prover_init(poly)?;
|
||||
let mut challenge = None;
|
||||
let mut prover_msgs = Vec::with_capacity(poly.domain_info.num_variables);
|
||||
for _ in 0..poly.domain_info.num_variables {
|
||||
let mut prover_msgs = Vec::with_capacity(poly.aux_info.num_variables);
|
||||
for _ in 0..poly.aux_info.num_variables {
|
||||
let prover_msg =
|
||||
IOPProverState::prove_round_and_update_state(&mut prover_state, &challenge)?;
|
||||
transcript.append_prover_message(&prover_msg)?;
|
||||
@@ -169,18 +164,18 @@ impl<F: PrimeField> SumCheck<F> for PolyIOP<F> {
|
||||
})
|
||||
}
|
||||
|
||||
/// verify the claimed sum using the proof
|
||||
/// Verify the claimed sum using the proof
|
||||
fn verify(
|
||||
claimed_sum: F,
|
||||
proof: &Self::Proof,
|
||||
domain_info: &Self::DomainInfo,
|
||||
aux_info: &Self::VPAuxInfo,
|
||||
transcript: &mut Self::Transcript,
|
||||
) -> Result<Self::SubClaim, PolyIOPErrors> {
|
||||
let start = start_timer!(|| "sum check verify");
|
||||
|
||||
transcript.append_domain_info(domain_info)?;
|
||||
let mut verifier_state = IOPVerifierState::verifier_init(domain_info);
|
||||
for i in 0..domain_info.num_variables {
|
||||
transcript.append_aux_info(aux_info)?;
|
||||
let mut verifier_state = IOPVerifierState::verifier_init(aux_info);
|
||||
for i in 0..aux_info.num_variables {
|
||||
let prover_msg = proof.proofs.get(i).expect("proof is incomplete");
|
||||
transcript.append_prover_message(prover_msg)?;
|
||||
IOPVerifierState::verify_round_and_update_state(
|
||||
@@ -218,7 +213,7 @@ mod test {
|
||||
let (poly, asserted_sum) =
|
||||
VirtualPolynomial::rand(nv, num_multiplicands_range, num_products, &mut rng)?;
|
||||
let proof = <PolyIOP<Fr> as SumCheck<Fr>>::prove(&poly, &mut transcript)?;
|
||||
let poly_info = poly.domain_info.clone();
|
||||
let poly_info = poly.aux_info.clone();
|
||||
let mut transcript = <PolyIOP<Fr> as SumCheck<Fr>>::init_transcript();
|
||||
let subclaim = <PolyIOP<Fr> as SumCheck<Fr>>::verify(
|
||||
asserted_sum,
|
||||
@@ -241,7 +236,7 @@ mod test {
|
||||
let mut rng = test_rng();
|
||||
let (poly, asserted_sum) =
|
||||
VirtualPolynomial::<Fr>::rand(nv, num_multiplicands_range, num_products, &mut rng)?;
|
||||
let poly_info = poly.domain_info.clone();
|
||||
let poly_info = poly.aux_info.clone();
|
||||
let mut prover_state = IOPProverState::prover_init(&poly)?;
|
||||
let mut verifier_state = IOPVerifierState::verifier_init(&poly_info);
|
||||
let mut challenge = None;
|
||||
@@ -249,7 +244,7 @@ mod test {
|
||||
transcript
|
||||
.append_message(b"testing", b"initializing transcript for testing")
|
||||
.unwrap();
|
||||
for _ in 0..poly.domain_info.num_variables {
|
||||
for _ in 0..poly.aux_info.num_variables {
|
||||
let prover_message =
|
||||
IOPProverState::prove_round_and_update_state(&mut prover_state, &challenge)
|
||||
.unwrap();
|
||||
@@ -362,7 +357,7 @@ mod test {
|
||||
drop(prover);
|
||||
|
||||
let mut transcript = <PolyIOP<Fr> as SumCheck<Fr>>::init_transcript();
|
||||
let poly_info = poly.domain_info.clone();
|
||||
let poly_info = poly.aux_info.clone();
|
||||
let proof = <PolyIOP<Fr> as SumCheck<Fr>>::prove(&poly, &mut transcript)?;
|
||||
let asserted_sum = <PolyIOP<Fr> as SumCheck<Fr>>::extract_sum(&proof);
|
||||
|
||||
|
||||
@@ -1,4 +1,4 @@
|
||||
//! Prover
|
||||
//! Prover subroutines for a SumCheck protocol.
|
||||
|
||||
use super::SumCheckProver;
|
||||
use crate::{
|
||||
@@ -15,14 +15,14 @@ use std::rc::Rc;
|
||||
use rayon::iter::{IndexedParallelIterator, IntoParallelRefMutIterator, ParallelIterator};
|
||||
|
||||
impl<F: PrimeField> SumCheckProver<F> for IOPProverState<F> {
|
||||
type PolyList = VirtualPolynomial<F>;
|
||||
type VirtualPolynomial = VirtualPolynomial<F>;
|
||||
type ProverMessage = IOPProverMessage<F>;
|
||||
|
||||
/// Initialize the prover to argue for the sum of polynomial over
|
||||
/// {0,1}^`num_vars`
|
||||
fn prover_init(polynomial: &Self::PolyList) -> Result<Self, PolyIOPErrors> {
|
||||
/// Initialize the prover state to argue for the sum of the input polynomial
|
||||
/// over {0,1}^`num_vars`.
|
||||
fn prover_init(polynomial: &Self::VirtualPolynomial) -> Result<Self, PolyIOPErrors> {
|
||||
let start = start_timer!(|| "sum check prover init");
|
||||
if polynomial.domain_info.num_variables == 0 {
|
||||
if polynomial.aux_info.num_variables == 0 {
|
||||
return Err(PolyIOPErrors::InvalidParameters(
|
||||
"Attempt to prove a constant.".to_string(),
|
||||
));
|
||||
@@ -30,14 +30,14 @@ impl<F: PrimeField> SumCheckProver<F> for IOPProverState<F> {
|
||||
end_timer!(start);
|
||||
|
||||
Ok(Self {
|
||||
challenges: Vec::with_capacity(polynomial.domain_info.num_variables),
|
||||
challenges: Vec::with_capacity(polynomial.aux_info.num_variables),
|
||||
round: 0,
|
||||
poly: polynomial.clone(),
|
||||
})
|
||||
}
|
||||
|
||||
/// Receive message from verifier, generate prover message, and proceed to
|
||||
/// next round
|
||||
/// next round.
|
||||
///
|
||||
/// Main algorithm used is from section 3.2 of [XZZPS19](https://eprint.iacr.org/2019/317.pdf#subsection.3.2).
|
||||
fn prove_round_and_update_state(
|
||||
@@ -47,8 +47,25 @@ impl<F: PrimeField> SumCheckProver<F> for IOPProverState<F> {
|
||||
let start =
|
||||
start_timer!(|| format!("sum check prove {}-th round and update state", self.round));
|
||||
|
||||
if self.round >= self.poly.aux_info.num_variables {
|
||||
return Err(PolyIOPErrors::InvalidProver(
|
||||
"Prover is not active".to_string(),
|
||||
));
|
||||
}
|
||||
|
||||
let fix_argument = start_timer!(|| "fix argument");
|
||||
|
||||
// Step 1:
|
||||
// fix argument and evaluate f(x) over x_m = r; where r is the challenge
|
||||
// for the current round, and m is the round number, indexed from 1
|
||||
//
|
||||
// i.e.:
|
||||
// at round m <=n, for each mle g(x_1, ... x_n) within the flattened_mle
|
||||
// which has already been evaluated to
|
||||
//
|
||||
// g(r_1, ..., r_{m-1}, x_m ... x_n)
|
||||
//
|
||||
// eval g over r_m, and mutate g to g(r_1, ... r_m,, x_{m+1}... x_n)
|
||||
let mut flattened_ml_extensions: Vec<DenseMultilinearExtension<F>> = self
|
||||
.poly
|
||||
.flattened_ml_extensions
|
||||
@@ -64,18 +81,16 @@ impl<F: PrimeField> SumCheckProver<F> for IOPProverState<F> {
|
||||
}
|
||||
self.challenges.push(*chal);
|
||||
|
||||
// fix argument
|
||||
let i = self.round;
|
||||
let r = self.challenges[i - 1];
|
||||
let r = self.challenges[self.round - 1];
|
||||
#[cfg(feature = "parallel")]
|
||||
flattened_ml_extensions
|
||||
.par_iter_mut()
|
||||
.for_each(|multiplicand| *multiplicand = multiplicand.fix_variables(&[r]));
|
||||
.for_each(|mle| *mle = mle.fix_variables(&[r]));
|
||||
|
||||
#[cfg(not(feature = "parallel"))]
|
||||
flattened_ml_extensions
|
||||
.iter_mut()
|
||||
.for_each(|multiplicand| *multiplicand = multiplicand.fix_variables(&[r]));
|
||||
.for_each(|mle| *mle = mle.fix_variables(&[r]));
|
||||
} else if self.round > 0 {
|
||||
return Err(PolyIOPErrors::InvalidProver(
|
||||
"verifier message is empty".to_string(),
|
||||
@@ -85,30 +100,22 @@ impl<F: PrimeField> SumCheckProver<F> for IOPProverState<F> {
|
||||
|
||||
self.round += 1;
|
||||
|
||||
if self.round > self.poly.domain_info.num_variables {
|
||||
return Err(PolyIOPErrors::InvalidProver(
|
||||
"Prover is not active".to_string(),
|
||||
));
|
||||
}
|
||||
|
||||
let products_list = self.poly.products.clone();
|
||||
let i = self.round;
|
||||
let nv = self.poly.domain_info.num_variables;
|
||||
let degree = self.poly.domain_info.max_degree; // the degree of univariate polynomial sent by prover at this round
|
||||
|
||||
let mut products_sum = Vec::with_capacity(degree + 1);
|
||||
products_sum.resize(degree + 1, F::zero());
|
||||
let mut products_sum = Vec::with_capacity(self.poly.aux_info.max_degree + 1);
|
||||
products_sum.resize(self.poly.aux_info.max_degree + 1, F::zero());
|
||||
|
||||
let compute_sum = start_timer!(|| "compute sum");
|
||||
// generate sum
|
||||
// Step 2: generate sum for the partial evaluated polynomial:
|
||||
// f(r_1, ... r_m,, x_{m+1}... x_n)
|
||||
|
||||
#[cfg(feature = "parallel")]
|
||||
products_sum.par_iter_mut().enumerate().for_each(|(t, e)| {
|
||||
for b in 0..1 << (nv - i) {
|
||||
for b in 0..1 << (self.poly.aux_info.num_variables - self.round) {
|
||||
// evaluate P_round(t)
|
||||
for (coefficient, products) in products_list.iter() {
|
||||
let num_multiplicands = products.len();
|
||||
let num_mles = products.len();
|
||||
let mut product = *coefficient;
|
||||
for &f in products.iter().take(num_multiplicands) {
|
||||
for &f in products.iter().take(num_mles) {
|
||||
let table = &flattened_ml_extensions[f]; // f's range is checked in init
|
||||
product *= table[b << 1] * (F::one() - F::from(t as u64))
|
||||
+ table[(b << 1) + 1] * F::from(t as u64);
|
||||
@@ -119,26 +126,23 @@ impl<F: PrimeField> SumCheckProver<F> for IOPProverState<F> {
|
||||
});
|
||||
|
||||
#[cfg(not(feature = "parallel"))]
|
||||
for b in 0..1 << (nv - i) {
|
||||
products_sum
|
||||
.iter_mut()
|
||||
.take(degree + 1)
|
||||
.enumerate()
|
||||
.for_each(|(t, e)| {
|
||||
// evaluate P_round(t)
|
||||
for (coefficient, products) in products_list.iter() {
|
||||
let num_multiplicands = products.len();
|
||||
let mut product = *coefficient;
|
||||
for &f in products.iter().take(num_multiplicands) {
|
||||
let table = &flattened_ml_extensions[f]; // f's range is checked in init
|
||||
product *= table[b << 1] * (F::one() - F::from(t as u64))
|
||||
+ table[(b << 1) + 1] * F::from(t as u64);
|
||||
}
|
||||
*e += product;
|
||||
products_sum.iter_mut().enumerate().for_each(|(t, e)| {
|
||||
for b in 0..1 << (self.poly.aux_info.num_variables - self.round) {
|
||||
// evaluate P_round(t)
|
||||
for (coefficient, products) in products_list.iter() {
|
||||
let num_mles = products.len();
|
||||
let mut product = *coefficient;
|
||||
for &f in products.iter().take(num_mles) {
|
||||
let table = &flattened_ml_extensions[f]; // f's range is checked in init
|
||||
product *= table[b << 1] * (F::one() - F::from(t as u64))
|
||||
+ table[(b << 1) + 1] * F::from(t as u64);
|
||||
}
|
||||
});
|
||||
}
|
||||
*e += product;
|
||||
}
|
||||
}
|
||||
});
|
||||
|
||||
// update prover's state to the partial evaluated polynomial
|
||||
self.poly.flattened_ml_extensions = flattened_ml_extensions
|
||||
.iter()
|
||||
.map(|x| Rc::new(x.clone()))
|
||||
|
||||
@@ -1,11 +1,11 @@
|
||||
// TODO: some of the struct is generic for Sum Checks and Zero Checks.
|
||||
// If so move them to src/structs.rs
|
||||
//! Verifier subroutines for a SumCheck protocol.
|
||||
|
||||
use super::SumCheckVerifier;
|
||||
use crate::{
|
||||
errors::PolyIOPErrors,
|
||||
structs::{DomainInfo, IOPProverMessage, IOPVerifierState, SubClaim},
|
||||
structs::{IOPProverMessage, IOPVerifierState, SubClaim},
|
||||
transcript::IOPTranscript,
|
||||
virtual_poly::VPAuxInfo,
|
||||
};
|
||||
use ark_ff::PrimeField;
|
||||
use ark_std::{end_timer, start_timer};
|
||||
@@ -14,14 +14,14 @@ use ark_std::{end_timer, start_timer};
|
||||
use rayon::iter::{IndexedParallelIterator, IntoParallelIterator, ParallelIterator};
|
||||
|
||||
impl<F: PrimeField> SumCheckVerifier<F> for IOPVerifierState<F> {
|
||||
type DomainInfo = DomainInfo<F>;
|
||||
type VPAuxInfo = VPAuxInfo<F>;
|
||||
type ProverMessage = IOPProverMessage<F>;
|
||||
type Challenge = F;
|
||||
type Transcript = IOPTranscript<F>;
|
||||
type SubClaim = SubClaim<F>;
|
||||
|
||||
/// initialize the verifier
|
||||
fn verifier_init(index_info: &Self::DomainInfo) -> Self {
|
||||
/// Initialize the verifier's state.
|
||||
fn verifier_init(index_info: &Self::VPAuxInfo) -> Self {
|
||||
let start = start_timer!(|| "sum check verifier init");
|
||||
let res = Self {
|
||||
round: 1,
|
||||
@@ -35,12 +35,12 @@ impl<F: PrimeField> SumCheckVerifier<F> for IOPVerifierState<F> {
|
||||
res
|
||||
}
|
||||
|
||||
/// Run verifier at current round, given prover message
|
||||
/// Run verifier for the current round, given a prover message.
|
||||
///
|
||||
/// Normally, this function should perform actual verification. Instead,
|
||||
/// `verify_round` only samples and stores randomness and perform
|
||||
/// verifications altogether in `check_and_generate_subclaim` at
|
||||
/// the last step.
|
||||
/// Note that `verify_round_and_update_state` only samples and stores
|
||||
/// challenges; and update the verifier's state accordingly. The actual
|
||||
/// verifications are deferred (in batch) to `check_and_generate_subclaim`
|
||||
/// at the last step.
|
||||
fn verify_round_and_update_state(
|
||||
&mut self,
|
||||
prover_msg: &Self::ProverMessage,
|
||||
@@ -55,23 +55,24 @@ impl<F: PrimeField> SumCheckVerifier<F> for IOPVerifierState<F> {
|
||||
));
|
||||
}
|
||||
|
||||
// Now, verifier should check if the received P(0) + P(1) = expected. The check
|
||||
// is moved to `check_and_generate_subclaim`, and will be done after the
|
||||
// last round.
|
||||
// In an interactive protocol, the verifier should
|
||||
//
|
||||
// 1. check if the received 'P(0) + P(1) = expected`.
|
||||
// 2. set `expected` to P(r)`
|
||||
//
|
||||
// When we turn the protocol to a non-interactive one, it is sufficient to defer
|
||||
// such checks to `check_and_generate_subclaim` after the last round.
|
||||
|
||||
let challenge = transcript.get_and_append_challenge(b"Internal round")?;
|
||||
self.challenges.push(challenge);
|
||||
self.polynomials_received
|
||||
.push(prover_msg.evaluations.to_vec());
|
||||
|
||||
// Now, verifier should set `expected` to P(r).
|
||||
// This operation is also moved to `check_and_generate_subclaim`,
|
||||
// and will be done after the last round.
|
||||
|
||||
if self.round == self.num_vars {
|
||||
// accept and close
|
||||
self.finished = true;
|
||||
} else {
|
||||
// proceed to the next round
|
||||
self.round += 1;
|
||||
}
|
||||
|
||||
@@ -79,10 +80,12 @@ impl<F: PrimeField> SumCheckVerifier<F> for IOPVerifierState<F> {
|
||||
Ok(challenge)
|
||||
}
|
||||
|
||||
/// verify the sumcheck phase, and generate the subclaim
|
||||
/// This function verifies the deferred checks in the interactive version of
|
||||
/// the protocol; and generate the subclaim. Returns an error if the
|
||||
/// proof failed to verify.
|
||||
///
|
||||
/// If the asserted sum is correct, then the multilinear polynomial
|
||||
/// evaluated at `subclaim.point` is `subclaim.expected_evaluation`.
|
||||
/// evaluated at `subclaim.point` will be `subclaim.expected_evaluation`.
|
||||
/// Otherwise, it is highly unlikely that those two will be equal.
|
||||
/// Larger field size guarantees smaller soundness error.
|
||||
fn check_and_generate_subclaim(
|
||||
@@ -102,6 +105,8 @@ impl<F: PrimeField> SumCheckVerifier<F> for IOPVerifierState<F> {
|
||||
));
|
||||
}
|
||||
|
||||
// the deferred check during the interactive phase:
|
||||
// 2. set `expected` to P(r)`
|
||||
#[cfg(feature = "parallel")]
|
||||
let mut expected_vec = self
|
||||
.polynomials_received
|
||||
@@ -137,6 +142,7 @@ impl<F: PrimeField> SumCheckVerifier<F> for IOPVerifierState<F> {
|
||||
interpolate_uni_poly::<F>(&evaluations, challenge)
|
||||
})
|
||||
.collect::<Result<Vec<_>, PolyIOPErrors>>()?;
|
||||
|
||||
// insert the asserted_sum to the first position of the expected vector
|
||||
expected_vec.insert(0, *asserted_sum);
|
||||
|
||||
@@ -146,6 +152,8 @@ impl<F: PrimeField> SumCheckVerifier<F> for IOPVerifierState<F> {
|
||||
.zip(expected_vec.iter())
|
||||
.take(self.num_vars)
|
||||
{
|
||||
// the deferred check during the interactive phase:
|
||||
// 1. check if the received 'P(0) + P(1) = expected`.
|
||||
if evaluations[0] + evaluations[1] != expected {
|
||||
return Err(PolyIOPErrors::InvalidProof(
|
||||
"Prover message is not consistent with the claim.".to_string(),
|
||||
@@ -154,8 +162,9 @@ impl<F: PrimeField> SumCheckVerifier<F> for IOPVerifierState<F> {
|
||||
}
|
||||
end_timer!(start);
|
||||
Ok(SubClaim {
|
||||
point: self.challenges.to_vec(),
|
||||
// the last expected value (unchecked) will be included in the subclaim
|
||||
point: self.challenges.clone(),
|
||||
// the last expected value (not checked within this function) will be included in the
|
||||
// subclaim
|
||||
expected_evaluation: expected_vec[self.num_vars],
|
||||
})
|
||||
}
|
||||
@@ -163,19 +172,20 @@ impl<F: PrimeField> SumCheckVerifier<F> for IOPVerifierState<F> {
|
||||
|
||||
/// Interpolate a uni-variate degree-`p_i.len()-1` polynomial and evaluate this
|
||||
/// polynomial at `eval_at`:
|
||||
///
|
||||
/// \sum_{i=0}^len p_i * (\prod_{j!=i} (eval_at - j)/(i-j) )
|
||||
///
|
||||
/// This implementation is linear in number of inputs in terms of field
|
||||
/// operations. It also has a quadratic term in primitive operations which is
|
||||
/// negligible compared to field operations.
|
||||
pub(crate) fn interpolate_uni_poly<F: PrimeField>(
|
||||
p_i: &[F],
|
||||
eval_at: F,
|
||||
) -> Result<F, PolyIOPErrors> {
|
||||
fn interpolate_uni_poly<F: PrimeField>(p_i: &[F], eval_at: F) -> Result<F, PolyIOPErrors> {
|
||||
let start = start_timer!(|| "sum check interpolate uni poly opt");
|
||||
|
||||
let mut res = F::zero();
|
||||
|
||||
// prod = \prod_{j!=i} (eval_at - j)
|
||||
// compute
|
||||
// - prod = \prod (eval_at - j)
|
||||
// - evals = [eval_at - j]
|
||||
let mut evals = vec![];
|
||||
let len = p_i.len();
|
||||
let mut prod = eval_at;
|
||||
@@ -188,6 +198,7 @@ pub(crate) fn interpolate_uni_poly<F: PrimeField>(
|
||||
}
|
||||
|
||||
for i in 0..len {
|
||||
// res += p_i * prod / (divisor * (eval_at - j))
|
||||
let divisor = get_divisor(i, len)?;
|
||||
let divisor_f = {
|
||||
if divisor < 0 {
|
||||
|
||||
Reference in New Issue
Block a user