Working

plonky2/src/fri/recursive_verifier.rs

@@ -3,9 +3,12 @@ use plonky2_field::extension_field::Extendable;
 use plonky2_util::{log2_strict, reverse_index_bits_in_place};
 
 use crate::fri::proof::{
-    FriInitialTreeProofTarget, FriProofTarget, FriQueryRoundTarget, FriQueryStepTarget,
+    FriChallengesTarget, FriInitialTreeProofTarget, FriProofTarget, FriQueryRoundTarget,
+    FriQueryStepTarget,
+};
+use crate::fri::structure::{
+    FriBatchInfoTarget, FriInstanceInfoTarget, FriOpenings, FriOpeningsTarget,
 };
-use crate::fri::structure::{FriBatchInfoTarget, FriInstanceInfoTarget, FriOpeningsTarget};
 use crate::fri::{FriConfig, FriParams};
 use crate::gadgets::interpolation::InterpolationGate;
 use crate::gates::gate::Gate;
@@ -107,16 +110,11 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
 
     fn fri_verify_proof_of_work<H: AlgebraicHasher<F>>(
         &mut self,
-        proof: &FriProofTarget<D>,
-        challenger: &mut RecursiveChallenger<F, H, D>,
+        fri_pow_response: Target,
         config: &FriConfig,
     ) {
-        let mut inputs = challenger.get_hash(self).elements.to_vec();
-        inputs.push(proof.pow_witness);
-
-        let hash = self.hash_n_to_m_no_pad::<H>(inputs, 1)[0];
         self.assert_leading_zeros(
-            hash,
+            fri_pow_response,
             config.proof_of_work_bits + (64 - F::order().bits()) as u32,
         );
     }
@@ -124,11 +122,10 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
     pub fn verify_fri_proof<C: GenericConfig<D, F = F>>(
         &mut self,
         instance: &FriInstanceInfoTarget<D>,
-        // Openings of the PLONK polynomials.
-        os: &OpeningSetTarget<D>,
+        os: &FriOpeningsTarget<D>,
+        challenges: &FriChallengesTarget<D>,
         initial_merkle_caps: &[MerkleCapTarget],
         proof: &FriProofTarget<D>,
-        challenger: &mut RecursiveChallenger<F, C::Hasher, D>,
         params: &FriParams,
     ) where
         C::Hasher: AlgebraicHasher<F>,
@@ -146,29 +143,10 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         // Size of the LDE domain.
         let n = params.lde_size();
 
-        challenger.observe_openings(&os.to_fri_openings());
-
-        // Scaling factor to combine polynomials.
-        let alpha = challenger.get_extension_challenge(self);
-
-        let betas = with_context!(
-            self,
-            "recover the random betas used in the FRI reductions.",
-            proof
-                .commit_phase_merkle_caps
-                .iter()
-                .map(|cap| {
-                    challenger.observe_cap(cap);
-                    challenger.get_extension_challenge(self)
-                })
-                .collect::<Vec<_>>()
-        );
-        challenger.observe_extension_elements(&proof.final_poly.0);
-
         with_context!(
             self,
             "check PoW",
-            self.fri_verify_proof_of_work::<C::Hasher>(proof, challenger, &params.config)
+            self.fri_verify_proof_of_work::<C::Hasher>(challenges.fri_pow_response, &params.config)
         );
 
         // Check that parameters are coherent.
@@ -181,7 +159,7 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         let precomputed_reduced_evals = with_context!(
             self,
             "precompute reduced evaluations",
-            PrecomputedReducedOpeningsTarget::from_os_and_alpha(&os.to_fri_openings(), alpha, self)
+            PrecomputedReducedOpeningsTarget::from_os_and_alpha(os, challenges.fri_alpha, self)
         );
 
         for (i, round_proof) in proof.query_round_proofs.iter().enumerate() {
@@ -201,13 +179,12 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
                 &format!("verify one (of {}) query rounds", num_queries),
                 self.fri_verifier_query_round::<C>(
                     instance,
-                    alpha,
+                    challenges,
                     &precomputed_reduced_evals,
                     initial_merkle_caps,
                     proof,
-                    challenger,
+                    challenges.fri_query_indices[i],
                     n,
-                    &betas,
                     round_proof,
                     params,
                 )
@@ -291,13 +268,12 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
     fn fri_verifier_query_round<C: GenericConfig<D, F = F>>(
         &mut self,
         instance: &FriInstanceInfoTarget<D>,
-        alpha: ExtensionTarget<D>,
+        challenges: &FriChallengesTarget<D>,
         precomputed_reduced_evals: &PrecomputedReducedOpeningsTarget<D>,
         initial_merkle_caps: &[MerkleCapTarget],
         proof: &FriProofTarget<D>,
-        challenger: &mut RecursiveChallenger<F, C::Hasher, D>,
+        x_index: Target,
         n: usize,
-        betas: &[ExtensionTarget<D>],
         round_proof: &FriQueryRoundTarget<D>,
         params: &FriParams,
     ) where
@@ -308,7 +284,6 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         // Note that this `low_bits` decomposition permits non-canonical binary encodings. Here we
         // verify that this has a negligible impact on soundness error.
         Self::assert_noncanonical_indices_ok(&params.config);
-        let x_index = challenger.get_challenge(self);
         let mut x_index_bits = self.low_bits(x_index, n_log, F::BITS);
 
         let cap_index =
@@ -341,7 +316,7 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
             self.fri_combine_initial::<C>(
                 instance,
                 &round_proof.initial_trees_proof,
-                alpha,
+                challenges.fri_alpha,
                 subgroup_x,
                 precomputed_reduced_evals,
                 params,
@@ -368,7 +343,7 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
                     x_index_within_coset_bits,
                     arity_bits,
                     evals,
-                    betas[i],
+                    challenges.fri_betas[i],
                 )
             );
 

plonky2/src/plonk/get_challenges.rs

@@ -3,7 +3,7 @@ use std::collections::HashSet;
 use plonky2_field::extension_field::Extendable;
 use plonky2_field::polynomial::PolynomialCoeffs;
 
-use crate::fri::proof::{CompressedFriProof, FriChallenges, FriProof};
+use crate::fri::proof::{CompressedFriProof, FriChallenges, FriProof, FriProofTarget};
 use crate::fri::verifier::{compute_evaluation, fri_combine_initial, PrecomputedReducedOpenings};
 use crate::gadgets::polynomial::PolynomialCoeffsExtTarget;
 use crate::hash::hash_types::{HashOutTarget, MerkleCapTarget, RichField};
@@ -15,7 +15,8 @@ use crate::plonk::circuit_data::CommonCircuitData;
 use crate::plonk::config::{AlgebraicHasher, GenericConfig, Hasher};
 use crate::plonk::proof::{
     CompressedProof, CompressedProofWithPublicInputs, FriInferredElements, OpeningSet,
-    OpeningSetTarget, Proof, ProofChallenges, ProofChallengesTarget, ProofWithPublicInputs,
+    OpeningSetTarget, Proof, ProofChallenges, ProofChallengesTarget, ProofTarget,
+    ProofWithPublicInputs, ProofWithPublicInputsTarget,
 };
 use crate::util::reverse_bits;
 
@@ -277,3 +278,44 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         }
     }
 }
+
+impl<const D: usize> ProofWithPublicInputsTarget<D> {
+    pub(crate) fn get_challenges<F: RichField + Extendable<D>, C: GenericConfig<D, F = F>>(
+        &self,
+        builder: &mut CircuitBuilder<F, D>,
+        public_inputs_hash: HashOutTarget,
+        inner_common_data: &CommonCircuitData<F, C, D>,
+    ) -> ProofChallengesTarget<D>
+    where
+        C::Hasher: AlgebraicHasher<F>,
+    {
+        let ProofTarget {
+            wires_cap,
+            plonk_zs_partial_products_cap,
+            quotient_polys_cap,
+            openings,
+            opening_proof:
+                FriProofTarget {
+                    commit_phase_merkle_caps,
+                    final_poly,
+                    pow_witness,
+                    ..
+                },
+        } = &self.proof;
+
+        let public_inputs_hash =
+            builder.hash_n_to_hash_no_pad::<C::InnerHasher>(self.public_inputs.clone());
+
+        builder.get_challenges(
+            public_inputs_hash,
+            wires_cap,
+            plonk_zs_partial_products_cap,
+            quotient_polys_cap,
+            openings,
+            commit_phase_merkle_caps,
+            final_poly,
+            *pow_witness,
+            inner_common_data,
+        )
+    }
+}

plonky2/src/plonk/recursive_verifier.rs

@@ -5,7 +5,9 @@ use crate::iop::challenger::RecursiveChallenger;
 use crate::plonk::circuit_builder::CircuitBuilder;
 use crate::plonk::circuit_data::{CommonCircuitData, VerifierCircuitTarget};
 use crate::plonk::config::{AlgebraicHasher, GenericConfig};
-use crate::plonk::proof::{OpeningSetTarget, ProofTarget, ProofWithPublicInputsTarget};
+use crate::plonk::proof::{
+    OpeningSetTarget, ProofChallengesTarget, ProofTarget, ProofWithPublicInputsTarget,
+};
 use crate::plonk::vanishing_poly::eval_vanishing_poly_recursively;
 use crate::plonk::vars::EvaluationTargets;
 use crate::util::reducing::ReducingFactorTarget;
@@ -13,7 +15,7 @@ use crate::with_context;
 
 impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
     /// Recursively verifies an inner proof.
-    pub fn verify_proof_with_pis<C: GenericConfig<D, F = F>>(
+    pub fn verify_proof<C: GenericConfig<D, F = F>>(
         &mut self,
         proof_with_pis: ProofWithPublicInputsTarget<D>,
         inner_verifier_data: &VerifierCircuitTarget,
@@ -21,27 +23,29 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
     ) where
         C::Hasher: AlgebraicHasher<F>,
     {
-        let ProofWithPublicInputsTarget {
-            proof,
-            public_inputs,
-        } = proof_with_pis;
+        assert_eq!(
+            proof_with_pis.public_inputs.len(),
+            inner_common_data.num_public_inputs
+        );
+        let public_inputs_hash =
+            self.hash_n_to_hash_no_pad::<C::InnerHasher>(proof_with_pis.public_inputs.clone());
+        let challenges = proof_with_pis.get_challenges(self, public_inputs_hash, inner_common_data);
 
-        assert_eq!(public_inputs.len(), inner_common_data.num_public_inputs);
-        let public_inputs_hash = self.hash_n_to_hash_no_pad::<C::InnerHasher>(public_inputs);
-
-        self.verify_proof(
-            proof,
+        self.verify_proof_with_challenges(
+            proof_with_pis.proof,
             public_inputs_hash,
+            challenges,
             inner_verifier_data,
             inner_common_data,
         );
     }
 
     /// Recursively verifies an inner proof.
-    pub fn verify_proof<C: GenericConfig<D, F = F>>(
+    fn verify_proof_with_challenges<C: GenericConfig<D, F = F>>(
         &mut self,
         proof: ProofTarget<D>,
         public_inputs_hash: HashOutTarget,
+        challenges: ProofChallengesTarget<D>,
         inner_verifier_data: &VerifierCircuitTarget,
         inner_common_data: &CommonCircuitData<F, C, D>,
     ) where
@@ -51,30 +55,6 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
 
         let num_challenges = inner_common_data.config.num_challenges;
 
-        let mut challenger = RecursiveChallenger::<F, C::Hasher, D>::new(self);
-
-        let (betas, gammas, alphas, zeta) =
-            with_context!(self, "observe proof and generates challenges", {
-                // Observe the instance.
-                let digest = HashOutTarget::from_vec(
-                    self.constants(&inner_common_data.circuit_digest.elements),
-                );
-                challenger.observe_hash(&digest);
-                challenger.observe_hash(&public_inputs_hash);
-
-                challenger.observe_cap(&proof.wires_cap);
-                let betas = challenger.get_n_challenges(self, num_challenges);
-                let gammas = challenger.get_n_challenges(self, num_challenges);
-
-                challenger.observe_cap(&proof.plonk_zs_partial_products_cap);
-                let alphas = challenger.get_n_challenges(self, num_challenges);
-
-                challenger.observe_cap(&proof.quotient_polys_cap);
-                let zeta = challenger.get_extension_challenge(self);
-
-                (betas, gammas, alphas, zeta)
-            });
-
         let local_constants = &proof.openings.constants;
         let local_wires = &proof.openings.wires;
         let vars = EvaluationTargets {
@@ -87,23 +67,24 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         let s_sigmas = &proof.openings.plonk_sigmas;
         let partial_products = &proof.openings.partial_products;
 
-        let zeta_pow_deg = self.exp_power_of_2_extension(zeta, inner_common_data.degree_bits);
+        let zeta_pow_deg =
+            self.exp_power_of_2_extension(challenges.plonk_zeta, inner_common_data.degree_bits);
         let vanishing_polys_zeta = with_context!(
             self,
             "evaluate the vanishing polynomial at our challenge point, zeta.",
             eval_vanishing_poly_recursively(
                 self,
                 inner_common_data,
-                zeta,
+                challenges.plonk_zeta,
                 zeta_pow_deg,
                 vars,
                 local_zs,
                 next_zs,
                 partial_products,
                 s_sigmas,
-                &betas,
-                &gammas,
-                &alphas,
+                &challenges.plonk_betas,
+                &challenges.plonk_gammas,
+                &challenges.plonk_alphas,
             )
         );
 
@@ -128,16 +109,16 @@ impl<F: RichField + Extendable<D>, const D: usize> CircuitBuilder<F, D> {
             proof.quotient_polys_cap,
         ];
 
-        let fri_instance = inner_common_data.get_fri_instance_target(self, zeta);
+        let fri_instance = inner_common_data.get_fri_instance_target(self, challenges.plonk_zeta);
         with_context!(
             self,
             "verify FRI proof",
             self.verify_fri_proof::<C>(
                 &fri_instance,
-                &proof.openings,
+                &proof.openings.to_fri_openings(),
+                &challenges.fri_challenges,
                 merkle_caps,
                 &proof.opening_proof,
-                &mut challenger,
                 &inner_common_data.fri_params,
             )
         );
@@ -392,7 +373,7 @@ mod tests {
             &inner_vd.constants_sigmas_cap,
         );
 
-        builder.verify_proof_with_pis(pt, &inner_data, &inner_cd);
+        builder.verify_proof(pt, &inner_data, &inner_cd);
 
         if print_gate_counts {
             builder.print_gate_counts(0);