IPA Solidity unit-test generator (#341)

* feat: Initial experiments with Solidity templating in Rust (IPA)

* feat: Dynamic compatibility uni-test for IPA

* chore: Apply suggestions

* chore: Move solidity-specific unit-test for IPA into separate module

Cargo.toml

@@ -72,6 +72,8 @@ anyhow = "1.0.72"
 tap = "1.0.1"
 tracing-texray = "0.2.0"
 tracing-subscriber = { version = "0.3.17", features = ["env-filter"] }
+handlebars = "5.1.0"
+serde_json = "1.0.1"
 
 [build-dependencies]
 vergen = { version = "8", features = ["build", "git", "gitcl"] }

src/provider/ipa_pc.rs

@@ -28,8 +28,8 @@ pub struct ProverKey<E: Engine> {
 #[derive(Debug, Serialize)]
 #[serde(bound = "")]
 pub struct VerifierKey<E: Engine> {
-  ck_v: Arc<CommitmentKey<E>>,
-  ck_s: CommitmentKey<E>,
+  pub(in crate::provider) ck_v: Arc<CommitmentKey<E>>,
+  pub(in crate::provider) ck_s: CommitmentKey<E>,
 }
 
 impl<E: Engine> SimpleDigestible for VerifierKey<E> {}
@@ -149,9 +149,9 @@ impl<E: Engine> InnerProductWitness<E> {
 #[derive(Clone, Debug, Serialize, Deserialize)]
 #[serde(bound = "")]
 pub struct InnerProductArgument<E: Engine> {
-  L_vec: Vec<CompressedCommitment<E>>,
-  R_vec: Vec<CompressedCommitment<E>>,
-  a_hat: E::Scalar,
+  pub(in crate::provider) L_vec: Vec<CompressedCommitment<E>>,
+  pub(in crate::provider) R_vec: Vec<CompressedCommitment<E>>,
+  pub(in crate::provider) a_hat: E::Scalar,
 }
 
 impl<E> InnerProductArgument<E>

src/provider/mod.rs

@@ -18,6 +18,7 @@ pub(crate) mod util;
 
 // crate-private modules
 mod keccak;
+mod tests;
 
 use crate::{
   provider::{
@@ -166,7 +167,7 @@ impl CurveCycleEquipped for PallasEngine {
 }
 
 #[cfg(test)]
-mod tests {
+mod test {
   use crate::provider::{
     bn256_grumpkin::{bn256, grumpkin},
     secp_secq::{secp256k1, secq256k1},

src/provider/pedersen.rs

@@ -33,7 +33,7 @@ where
   // this is a hack; we just assume the size of the element.
   // Look for the static assertions in provider macros for a justification
   #[abomonate_with(Vec<[u64; 8]>)]
-  ck: Vec<<E::GE as PrimeCurve>::Affine>,
+  pub(in crate::provider) ck: Vec<<E::GE as PrimeCurve>::Affine>,
 }
 
 impl<E> Len for CommitmentKey<E>
@@ -65,7 +65,7 @@ where
   E: Engine,
   E::GE: DlogGroup<ScalarExt = E::Scalar>,
 {
-  comm: <E::GE as DlogGroup>::Compressed,
+  pub(crate) comm: <E::GE as DlogGroup>::Compressed,
 }
 
 impl<E> CommitmentTrait<E> for Commitment<E>

src/provider/tests/ipa_pc.rs

@@ -0,0 +1,129 @@
+#[cfg(test)]
+mod test {
+  use crate::provider::ipa_pc::EvaluationEngine;
+  use crate::provider::tests::solidity_compatibility_utils::{
+    ec_points_to_json, field_elements_to_json, generate_pcs_solidity_unit_test_data,
+  };
+
+  use crate::provider::GrumpkinEngine;
+  use group::Curve;
+
+  use crate::provider::pedersen::{CommitmentKey, CommitmentKeyExtTrait};
+  use handlebars::Handlebars;
+  use serde_json::json;
+  use serde_json::{Map, Value};
+
+  static IPA_COMPATIBILITY_UNIT_TESTING_TEMPLATE: &str = "
+// SPDX-License-Identifier: Apache-2.0
+pragma solidity ^0.8.16;
+import \"@std/Test.sol\";
+import \"src/blocks/grumpkin/Grumpkin.sol\";
+import \"src/blocks/EqPolynomial.sol\";
+import \"src/Utilities.sol\";
+import \"src/blocks/IpaPcs.sol\";
+
+contract IpaTest is Test {
+function composeIpaInput() public pure returns (InnerProductArgument.IpaInputGrumpkin memory) {
+Grumpkin.GrumpkinAffinePoint[] memory ck_v = new Grumpkin.GrumpkinAffinePoint[]({{ len ck_v }});
+{{ #each ck_v }} ck_v[{{ i }}]=Grumpkin.GrumpkinAffinePoint({{ x }}, {{y}});\n {{ /each }}
+
+Grumpkin.GrumpkinAffinePoint[] memory ck_s = new Grumpkin.GrumpkinAffinePoint[]({{ len ck_s }});
+{{ #each ck_s }} ck_s[{{ i }}]=Grumpkin.GrumpkinAffinePoint({{ x }}, {{y}});\n {{ /each }}
+
+uint256[] memory point = new uint256[]({{ len point }});
+{{ #each point }} point[{{ i }}]={{ val }};\n {{ /each }}
+
+Grumpkin.GrumpkinAffinePoint[] memory L_vec = new Grumpkin.GrumpkinAffinePoint[]({{ len L_vec }});
+{{ #each L_vec }} L_vec[{{ i }}]=Grumpkin.GrumpkinAffinePoint({{ x }}, {{y}});\n {{ /each }}
+
+Grumpkin.GrumpkinAffinePoint[] memory R_vec = new Grumpkin.GrumpkinAffinePoint[]({{ len R_vec }});
+{{ #each R_vec }} R_vec[{{ i }}]=Grumpkin.GrumpkinAffinePoint({{ x }}, {{y}});\n {{ /each }}
+
+uint256 a_hat = {{ a_hat }};
+
+// InnerProductInstance
+Grumpkin.GrumpkinAffinePoint memory commitment = Grumpkin.GrumpkinAffinePoint({{ commitment_x }}, {{ commitment_y }});
+
+uint256 eval = {{ eval }};
+
+return InnerProductArgument.IpaInputGrumpkin(ck_v, ck_s, point, L_vec, R_vec, commitment, eval, a_hat);
+}
+
+function testIpaGrumpkinVerification_{{ num_vars }}_Variables() public {
+InnerProductArgument.IpaInputGrumpkin memory input = composeIpaInput();
+assertTrue(InnerProductArgument.verifyGrumpkin(input, getTranscript()));
+}
+
+function getTranscript() public pure returns (KeccakTranscriptLib.KeccakTranscript memory) {
+// b\"TestEval\" in Rust
+uint8[] memory label = new uint8[](8);
+label[0] = 0x54;
+label[1] = 0x65;
+label[2] = 0x73;
+label[3] = 0x74;
+label[4] = 0x45;
+label[5] = 0x76;
+label[6] = 0x61;
+label[7] = 0x6c;
+
+KeccakTranscriptLib.KeccakTranscript memory keccak_transcript = KeccakTranscriptLib.instantiate(label);
+return keccak_transcript;
+}
+}
+";
+
+  // To generate Solidity unit-test:
+  // cargo test test_solidity_compatibility_ipa --release -- --ignored --nocapture > ipa.t.sol
+  #[test]
+  #[ignore]
+  fn test_solidity_compatibility_ipa() {
+    let num_vars = 2;
+
+    // Secondary part of verification is IPA over Grumpkin
+    let (commitment, point, eval, proof, vk) =
+      generate_pcs_solidity_unit_test_data::<_, EvaluationEngine<GrumpkinEngine>>(num_vars);
+
+    let num_vars_string = format!("{}", num_vars);
+    let eval_string = format!("{:?}", eval);
+    let commitment_x_string = format!("{:?}", commitment.comm.to_affine().x);
+    let commitment_y_string = format!("{:?}", commitment.comm.to_affine().y);
+    let proof_a_hat_string = format!("{:?}", proof.a_hat);
+
+    let r_vec = CommitmentKey::<GrumpkinEngine>::reinterpret_commitments_as_ck(&proof.R_vec)
+      .expect("can't reinterpred R_vec");
+    let l_vec = CommitmentKey::<GrumpkinEngine>::reinterpret_commitments_as_ck(&proof.L_vec)
+      .expect("can't reinterpred L_vec");
+
+    let r_vec_array = ec_points_to_json::<GrumpkinEngine>(&r_vec.ck);
+    let l_vec_array = ec_points_to_json::<GrumpkinEngine>(&l_vec.ck);
+    let point_array = field_elements_to_json::<GrumpkinEngine>(&point);
+    let ckv_array = ec_points_to_json::<GrumpkinEngine>(&vk.ck_v.ck);
+    let cks_array = ec_points_to_json::<GrumpkinEngine>(&vk.ck_s.ck);
+
+    let mut map = Map::new();
+    map.insert("num_vars".to_string(), Value::String(num_vars_string));
+    map.insert("eval".to_string(), Value::String(eval_string));
+    map.insert(
+      "commitment_x".to_string(),
+      Value::String(commitment_x_string),
+    );
+    map.insert(
+      "commitment_y".to_string(),
+      Value::String(commitment_y_string),
+    );
+    map.insert("R_vec".to_string(), Value::Array(r_vec_array));
+    map.insert("L_vec".to_string(), Value::Array(l_vec_array));
+    map.insert("a_hat".to_string(), Value::String(proof_a_hat_string));
+    map.insert("point".to_string(), Value::Array(point_array));
+    map.insert("ck_v".to_string(), Value::Array(ckv_array));
+    map.insert("ck_s".to_string(), Value::Array(cks_array));
+
+    let mut reg = Handlebars::new();
+    reg
+      .register_template_string("ipa.t.sol", IPA_COMPATIBILITY_UNIT_TESTING_TEMPLATE)
+      .expect("can't register template");
+
+    let solidity_unit_test_source = reg.render("ipa.t.sol", &json!(map)).expect("can't render");
+    println!("{}", solidity_unit_test_source);
+  }
+}

src/provider/tests/mod.rs

@@ -0,0 +1,124 @@
+mod ipa_pc;
+
+#[cfg(test)]
+pub mod solidity_compatibility_utils {
+  use crate::provider::traits::DlogGroup;
+  use crate::spartan::polys::multilinear::MultilinearPolynomial;
+  use crate::traits::{
+    commitment::CommitmentEngineTrait, evaluation::EvaluationEngineTrait, Engine,
+  };
+  use group::prime::PrimeCurve;
+  use group::prime::PrimeCurveAffine;
+  use rand::rngs::StdRng;
+  use serde_json::{Map, Value};
+  use std::sync::Arc;
+
+  pub(crate) fn generate_pcs_solidity_unit_test_data<E: Engine, EE: EvaluationEngineTrait<E>>(
+    num_vars: usize,
+  ) -> (
+    <E::CE as CommitmentEngineTrait<E>>::Commitment,
+    Vec<E::Scalar>,
+    E::Scalar,
+    EE::EvaluationArgument,
+    EE::VerifierKey,
+  ) {
+    use rand_core::SeedableRng;
+
+    let mut rng = rand::rngs::StdRng::seed_from_u64(num_vars as u64);
+
+    let (poly, point, eval) =
+      crate::provider::util::test_utils::random_poly_with_eval::<E, StdRng>(num_vars, &mut rng);
+
+    // Mock commitment key.
+    let ck = E::CE::setup(b"test", 1 << num_vars);
+    let ck_arc = Arc::new(ck.clone());
+    // Commits to the provided vector using the provided generators.
+    let commitment = E::CE::commit(&ck_arc, poly.evaluations());
+
+    let (proof, vk) = prove_verify_solidity::<E, EE>(ck_arc, &commitment, &poly, &point, &eval);
+
+    (commitment, point, eval, proof, vk)
+  }
+
+  fn prove_verify_solidity<E: Engine, EE: EvaluationEngineTrait<E>>(
+    ck: Arc<<<E as Engine>::CE as CommitmentEngineTrait<E>>::CommitmentKey>,
+    commitment: &<<E as Engine>::CE as CommitmentEngineTrait<E>>::Commitment,
+    poly: &MultilinearPolynomial<<E as Engine>::Scalar>,
+    point: &[<E as Engine>::Scalar],
+    eval: &<E as Engine>::Scalar,
+  ) -> (EE::EvaluationArgument, EE::VerifierKey) {
+    use crate::traits::TranscriptEngineTrait;
+
+    // Generate Prover and verifier key for given commitment key.
+    let ock = ck.clone();
+    let (prover_key, verifier_key) = EE::setup(ck);
+
+    // Generate proof.
+    let mut prover_transcript = E::TE::new(b"TestEval");
+    let proof: EE::EvaluationArgument = EE::prove(
+      &*ock,
+      &prover_key,
+      &mut prover_transcript,
+      commitment,
+      poly.evaluations(),
+      point,
+      eval,
+    )
+    .unwrap();
+    let pcp = prover_transcript.squeeze(b"c").unwrap();
+
+    // Verify proof.
+    let mut verifier_transcript = E::TE::new(b"TestEval");
+    EE::verify(
+      &verifier_key,
+      &mut verifier_transcript,
+      commitment,
+      point,
+      eval,
+      &proof,
+    )
+    .unwrap();
+    let pcv = verifier_transcript.squeeze(b"c").unwrap();
+
+    // Check if the prover transcript and verifier transcript are kept in the same state.
+    assert_eq!(pcp, pcv);
+
+    (proof, verifier_key)
+  }
+
+  pub(crate) fn field_elements_to_json<E: Engine>(field_elements: &[E::Scalar]) -> Vec<Value> {
+    let mut value_vector = vec![];
+    field_elements.iter().enumerate().for_each(|(i, fe)| {
+      let mut value = Map::new();
+      value.insert("i".to_string(), Value::String(i.to_string()));
+      value.insert("val".to_string(), Value::String(format!("{:?}", fe)));
+      value_vector.push(Value::Object(value));
+    });
+    value_vector
+  }
+
+  pub(crate) fn ec_points_to_json<E>(ec_points: &[<E::GE as PrimeCurve>::Affine]) -> Vec<Value>
+  where
+    E: Engine,
+    E::GE: DlogGroup<ScalarExt = E::Scalar>,
+  {
+    let mut value_vector = vec![];
+    ec_points.iter().enumerate().for_each(|(i, ec_point)| {
+      let mut value = Map::new();
+      let coordinates_info = ec_point.to_curve().to_coordinates();
+      let not_infinity = !coordinates_info.2;
+      assert!(not_infinity);
+      value.insert("i".to_string(), Value::String(i.to_string()));
+      value.insert(
+        "x".to_string(),
+        Value::String(format!("{:?}", coordinates_info.0)),
+      );
+      value.insert(
+        "y".to_string(),
+        Value::String(format!("{:?}", coordinates_info.1)),
+      );
+      value_vector.push(Value::Object(value));
+    });
+    value_vector
+  }
+}

src/provider/util/mod.rs

@@ -116,7 +116,7 @@ pub mod test_utils {
   use std::sync::Arc;
 
   /// Returns a random polynomial, a point and calculate its evaluation.
-  fn random_poly_with_eval<E: Engine, R: RngCore + CryptoRng>(
+  pub(crate) fn random_poly_with_eval<E: Engine, R: RngCore + CryptoRng>(
     num_vars: usize,
     mut rng: &mut R,
   ) -> (