chore: clean up proof lengths and IPA (#11020)

Closes AztecProtocol/barretenberg#1184.
Closes AztecProtocol/barretenberg#1168.

Cleans up some ugliness by deduplication and refactoring. Also adds new
UltraRollupHonk tests and a new test for checking proof lengths.

Author: lucasxia01

barretenberg/cpp/src/barretenberg/bb/main.cpp

@@ -228,10 +228,10 @@ void prove_tube(const std::string& output_path)
     // circuit
     // TODO(https://github.com/AztecProtocol/barretenberg/issues/1048): INSECURE - make this tube proof actually use
     // these public inputs by turning proof into witnesses and calling set_public on each witness
-    auto num_public_inputs = static_cast<uint32_t>(static_cast<uint256_t>(proof.mega_proof[1]));
-    num_public_inputs -= bb::PAIRING_POINT_ACCUMULATOR_SIZE; // don't add the agg object
+    auto num_inner_public_inputs = static_cast<uint32_t>(static_cast<uint256_t>(proof.mega_proof[1]));
+    num_inner_public_inputs -= bb::PAIRING_POINT_ACCUMULATOR_SIZE; // don't add the agg object
 
-    for (size_t i = 0; i < num_public_inputs; i++) {
+    for (size_t i = 0; i < num_inner_public_inputs; i++) {
         auto offset = bb::HONK_PROOF_PUBLIC_INPUT_OFFSET;
         builder->add_public_variable(proof.mega_proof[i + offset]);
     }
@@ -278,13 +278,13 @@ void prove_tube(const std::string& output_path)
     Verifier tube_verifier(tube_verification_key, ipa_verification_key);
 
     // Break up the tube proof into the honk portion and the ipa portion
-    // TODO(https://github.com/AztecProtocol/barretenberg/issues/1168): Add formula to flavor
-    const size_t HONK_PROOF_LENGTH = 469;
+    const size_t HONK_PROOF_LENGTH_WITHOUT_INNER_PUB_INPUTS =
+        UltraRollupFlavor::PROOF_LENGTH_WITHOUT_PUB_INPUTS + PAIRING_POINT_ACCUMULATOR_SIZE + IPA_CLAIM_SIZE;
     // The extra calculation is for the IPA proof length.
-    ASSERT(tube_proof.size() == HONK_PROOF_LENGTH + 1 + 4 * (CONST_ECCVM_LOG_N) + 2 + 2 + num_public_inputs);
+    ASSERT(tube_proof.size() == HONK_PROOF_LENGTH_WITHOUT_INNER_PUB_INPUTS + num_inner_public_inputs);
     // split out the ipa proof
-    const std::ptrdiff_t honk_proof_with_pub_inputs_length =
-        static_cast<std::ptrdiff_t>(HONK_PROOF_LENGTH + num_public_inputs);
+    const std::ptrdiff_t honk_proof_with_pub_inputs_length = static_cast<std::ptrdiff_t>(
+        HONK_PROOF_LENGTH_WITHOUT_INNER_PUB_INPUTS - IPA_PROOF_LENGTH + num_inner_public_inputs);
     auto ipa_proof = HonkProof(tube_proof.begin() + honk_proof_with_pub_inputs_length, tube_proof.end());
     auto tube_honk_proof = HonkProof(tube_proof.begin(), tube_proof.end() + honk_proof_with_pub_inputs_length);
     bool verified = tube_verifier.verify_proof(tube_honk_proof, ipa_proof);
@@ -895,15 +895,13 @@ template <IsUltraFlavor Flavor> bool verify_honk(const std::string& proof_path,
     bool verified;
     if constexpr (HasIPAAccumulator<Flavor>) {
         // Break up the tube proof into the honk portion and the ipa portion
-        // TODO(https://github.com/AztecProtocol/barretenberg/issues/1168): Add formula to flavor
-        const size_t HONK_PROOF_LENGTH = 469;
-        const size_t num_public_inputs =
-            static_cast<size_t>(uint64_t(proof[1])) - PAIRING_POINT_ACCUMULATOR_SIZE - IPA_CLAIM_SIZE;
+        const size_t HONK_PROOF_LENGTH = Flavor::PROOF_LENGTH_WITHOUT_PUB_INPUTS - IPA_PROOF_LENGTH;
+        const size_t num_public_inputs = static_cast<size_t>(uint64_t(proof[1]));
         // The extra calculation is for the IPA proof length.
         debug("proof size: ", proof.size());
         debug("num public inputs: ", num_public_inputs);
         // TODO(https://github.com/AztecProtocol/barretenberg/issues/1182): Move to ProofSurgeon.
-        ASSERT(proof.size() == HONK_PROOF_LENGTH + 1 + 4 * (CONST_ECCVM_LOG_N) + 2 + 2 + num_public_inputs);
+        ASSERT(proof.size() == HONK_PROOF_LENGTH + IPA_PROOF_LENGTH + num_public_inputs);
         // split out the ipa proof
         const std::ptrdiff_t honk_proof_with_pub_inputs_length =
             static_cast<std::ptrdiff_t>(HONK_PROOF_LENGTH + num_public_inputs);

barretenberg/cpp/src/barretenberg/commitment_schemes/ipa/ipa.hpp

@@ -6,9 +6,11 @@
 #include "barretenberg/common/container.hpp"
 #include "barretenberg/common/thread.hpp"
 #include "barretenberg/common/throw_or_abort.hpp"
+#include "barretenberg/constants.hpp"
 #include "barretenberg/ecc/scalar_multiplication/scalar_multiplication.hpp"
 #include "barretenberg/stdlib/hash/poseidon2/poseidon2.hpp"
 #include "barretenberg/stdlib/honk_verifier/ipa_accumulator.hpp"
+#include "barretenberg/stdlib/primitives/circuit_builders/circuit_builders_fwd.hpp"
 #include "barretenberg/stdlib/transcript/transcript.hpp"
 #include "barretenberg/transcript/transcript.hpp"
 #include <cstddef>
@@ -20,6 +22,8 @@
 namespace bb {
 // clang-format off
 
+constexpr size_t IPA_PROOF_LENGTH = 1 + 4 * CONST_ECCVM_LOG_N + 2 + 2;
+
 /**
 * @brief IPA (inner product argument) commitment scheme class.
 *
@@ -949,6 +953,32 @@ template <typename Curve_> class IPA {
         output_claim.opening_pair.evaluation.self_reduce();
         return {output_claim, prover_transcript->proof_data};
     }
+
+    static std::pair<OpeningClaim<Curve>, HonkProof> create_fake_ipa_claim_and_proof(UltraCircuitBuilder& builder)
+    requires Curve::is_stdlib_type {
+        using NativeCurve = curve::Grumpkin;
+        using Builder = typename Curve::Builder;
+        using Curve = stdlib::grumpkin<Builder>;
+        auto ipa_transcript = std::make_shared<NativeTranscript>();
+        auto ipa_commitment_key = std::make_shared<CommitmentKey<NativeCurve>>(1 << CONST_ECCVM_LOG_N);
+        size_t n = 4;
+        auto poly = Polynomial<fq>(n);
+        for (size_t i = 0; i < n; i++) {
+            poly.at(i) = fq::random_element();
+        }
+        fq x = fq::random_element();
+        fq eval = poly.evaluate(x);
+        auto commitment = ipa_commitment_key->commit(poly);
+        const OpeningPair<NativeCurve> opening_pair = { x, eval };
+        IPA<NativeCurve>::compute_opening_proof(ipa_commitment_key, { poly, opening_pair }, ipa_transcript);
+
+        auto stdlib_comm = Curve::Group::from_witness(&builder, commitment);
+        auto stdlib_x = Curve::ScalarField::from_witness(&builder, x);
+        auto stdlib_eval = Curve::ScalarField::from_witness(&builder, eval);
+        OpeningClaim<Curve> stdlib_opening_claim{ { stdlib_x, stdlib_eval }, stdlib_comm };
+
+        return {stdlib_opening_claim, ipa_transcript->export_proof()};
+    }
 };
 
 } // namespace bb

barretenberg/cpp/src/barretenberg/dsl/acir_format/acir_format.cpp

@@ -439,31 +439,13 @@ HonkRecursionConstraintsOutput<Builder> process_honk_recursion_constraints(
     } else if (nested_ipa_claims.size() > 2) {
         throw_or_abort("Too many nested IPA claims to accumulate");
     } else {
-        // TODO(https://github.com/AztecProtocol/barretenberg/issues/1184): Move to IPA class.
         if (honk_recursion == 2) {
             info("Proving with UltraRollupHonk but no IPA claims exist.");
-            // just create some fake IPA claim and proof
-            using NativeCurve = curve::Grumpkin;
-            using Curve = stdlib::grumpkin<Builder>;
-            auto ipa_transcript = std::make_shared<NativeTranscript>();
-            auto ipa_commitment_key = std::make_shared<CommitmentKey<NativeCurve>>(1 << CONST_ECCVM_LOG_N);
-            size_t n = 4;
-            auto poly = Polynomial<fq>(n);
-            for (size_t i = 0; i < n; i++) {
-                poly.at(i) = fq::random_element();
-            }
-            fq x = fq::random_element();
-            fq eval = poly.evaluate(x);
-            auto commitment = ipa_commitment_key->commit(poly);
-            const OpeningPair<NativeCurve> opening_pair = { x, eval };
-            IPA<NativeCurve>::compute_opening_proof(ipa_commitment_key, { poly, opening_pair }, ipa_transcript);
-
-            auto stdlib_comm = Curve::Group::from_witness(&builder, commitment);
-            auto stdlib_x = Curve::ScalarField::from_witness(&builder, x);
-            auto stdlib_eval = Curve::ScalarField::from_witness(&builder, eval);
-            OpeningClaim<Curve> stdlib_opening_claim{ { stdlib_x, stdlib_eval }, stdlib_comm };
+            auto [stdlib_opening_claim, ipa_proof] =
+                IPA<stdlib::grumpkin<Builder>>::create_fake_ipa_claim_and_proof(builder);
+
             output.ipa_claim = stdlib_opening_claim;
-            output.ipa_proof = ipa_transcript->export_proof();
+            output.ipa_proof = ipa_proof;
         }
     }
     output.agg_obj_indices = current_aggregation_object;

barretenberg/cpp/src/barretenberg/dsl/acir_format/honk_recursion_constraint.cpp

@@ -42,18 +42,9 @@ void create_dummy_vkey_and_proof(Builder& builder,
                                  const std::vector<field_ct>& proof_fields)
 {
     // Set vkey->circuit_size correctly based on the proof size
-    size_t num_frs_comm = bb::field_conversion::calc_num_bn254_frs<typename Flavor::Commitment>();
-    size_t num_frs_fr = bb::field_conversion::calc_num_bn254_frs<typename Flavor::FF>();
-    // TODO(https://github.com/AztecProtocol/barretenberg/issues/1168): Add formula to flavor
-    assert((proof_size - bb::HONK_PROOF_PUBLIC_INPUT_OFFSET - Flavor::NUM_WITNESS_ENTITIES * num_frs_comm -
-            Flavor::NUM_ALL_ENTITIES * num_frs_fr - num_frs_comm) %
-               (num_frs_comm + num_frs_fr * (Flavor::BATCHED_RELATION_PARTIAL_LENGTH + 1)) ==
-           0);
+    ASSERT(proof_size == Flavor::PROOF_LENGTH_WITHOUT_PUB_INPUTS);
     // Note: this computation should always result in log_circuit_size = CONST_PROOF_SIZE_LOG_N
-    auto log_circuit_size =
-        (proof_size - bb::HONK_PROOF_PUBLIC_INPUT_OFFSET - Flavor::NUM_WITNESS_ENTITIES * num_frs_comm -
-         Flavor::NUM_ALL_ENTITIES * num_frs_fr - num_frs_comm) /
-        (num_frs_comm + num_frs_fr * (Flavor::BATCHED_RELATION_PARTIAL_LENGTH + 1));
+    auto log_circuit_size = CONST_PROOF_SIZE_LOG_N;
     // First key field is circuit size
     builder.assert_equal(builder.add_variable(1 << log_circuit_size), key_fields[0].witness_index);
     // Second key field is number of public inputs

barretenberg/cpp/src/barretenberg/stdlib/honk_verifier/ultra_recursive_verifier.cpp

@@ -49,16 +49,14 @@ UltraRecursiveVerifier_<Flavor>::Output UltraRecursiveVerifier_<Flavor>::verify_
     Output output;
     StdlibProof<Builder> honk_proof;
     if constexpr (HasIPAAccumulator<Flavor>) {
-        // TODO(https://github.com/AztecProtocol/barretenberg/issues/1168): Add formula to flavor
-        const size_t HONK_PROOF_LENGTH = 469;
+        const size_t HONK_PROOF_LENGTH = Flavor::NativeFlavor::PROOF_LENGTH_WITHOUT_PUB_INPUTS - IPA_PROOF_LENGTH;
         const size_t num_public_inputs = static_cast<uint32_t>(proof[1].get_value());
         // The extra calculation is for the IPA proof length.
         // TODO(https://github.com/AztecProtocol/barretenberg/issues/1182): Handle in ProofSurgeon.
-        ASSERT(proof.size() == HONK_PROOF_LENGTH + (1 + 4 * (CONST_ECCVM_LOG_N) + 2 + 2) + num_public_inputs -
-                                   (PAIRING_POINT_ACCUMULATOR_SIZE + IPA_CLAIM_SIZE));
+        ASSERT(proof.size() == HONK_PROOF_LENGTH + IPA_PROOF_LENGTH + num_public_inputs);
         // split out the ipa proof
-        const std::ptrdiff_t honk_proof_with_pub_inputs_length = static_cast<std::ptrdiff_t>(
-            HONK_PROOF_LENGTH + num_public_inputs - (PAIRING_POINT_ACCUMULATOR_SIZE + IPA_CLAIM_SIZE));
+        const std::ptrdiff_t honk_proof_with_pub_inputs_length =
+            static_cast<std::ptrdiff_t>(HONK_PROOF_LENGTH + num_public_inputs);
         output.ipa_proof = StdlibProof<Builder>(proof.begin() + honk_proof_with_pub_inputs_length, proof.end());
         honk_proof = StdlibProof<Builder>(proof.begin(), proof.end() + honk_proof_with_pub_inputs_length);
     } else {

barretenberg/cpp/src/barretenberg/stdlib/honk_verifier/ultra_recursive_verifier.test.cpp

@@ -77,29 +77,11 @@ template <typename RecursiveFlavor> class RecursiveVerifierTest : public testing
         PairingPointAccumulatorIndices agg_obj_indices = stdlib::recursion::init_default_agg_obj_indices(builder);
         builder.add_pairing_point_accumulator(agg_obj_indices);
 
-        // TODO(https://github.com/AztecProtocol/barretenberg/issues/1184): Move to IPA class.
         if constexpr (HasIPAAccumulator<RecursiveFlavor>) {
-            using NativeCurve = curve::Grumpkin;
-            using Curve = stdlib::grumpkin<InnerBuilder>;
-            auto ipa_transcript = std::make_shared<NativeTranscript>();
-            auto ipa_commitment_key = std::make_shared<CommitmentKey<NativeCurve>>(1 << CONST_ECCVM_LOG_N);
-            size_t n = 4;
-            auto poly = Polynomial<fq>(n);
-            for (size_t i = 0; i < n; i++) {
-                poly.at(i) = fq::random_element();
-            }
-            fq x = fq::random_element();
-            fq eval = poly.evaluate(x);
-            auto commitment = ipa_commitment_key->commit(poly);
-            const OpeningPair<NativeCurve> opening_pair = { x, eval };
-            IPA<NativeCurve>::compute_opening_proof(ipa_commitment_key, { poly, opening_pair }, ipa_transcript);
-
-            auto stdlib_comm = Curve::Group::from_witness(&builder, commitment);
-            auto stdlib_x = Curve::ScalarField::from_witness(&builder, x);
-            auto stdlib_eval = Curve::ScalarField::from_witness(&builder, eval);
-            OpeningClaim<Curve> stdlib_opening_claim{ { stdlib_x, stdlib_eval }, stdlib_comm };
+            auto [stdlib_opening_claim, ipa_proof] =
+                IPA<grumpkin<InnerBuilder>>::create_fake_ipa_claim_and_proof(builder);
             builder.add_ipa_claim(stdlib_opening_claim.get_witness_indices());
-            builder.ipa_proof = ipa_transcript->export_proof();
+            builder.ipa_proof = ipa_proof;
         }
         return builder;
     };

barretenberg/cpp/src/barretenberg/stdlib_circuit_builders/ultra_flavor.hpp

@@ -67,9 +67,9 @@ class UltraFlavor {
     // Note: made generic for use in MegaRecursive.
     template <typename FF>
 
-    // List of relations reflecting the Ultra arithmetisation. WARNING: As UltraKeccak flavor inherits from Ultra flavor
-    // any change of ordering in this tuple needs to be reflected in the smart contract, otherwise relation accumulation
-    // will not match.
+    // List of relations reflecting the Ultra arithmetisation. WARNING: As UltraKeccak flavor inherits from
+    // Ultra flavor any change of ordering in this tuple needs to be reflected in the smart contract, otherwise
+    // relation accumulation will not match.
     using Relations_ = std::tuple<bb::UltraArithmeticRelation<FF>,
                                   bb::UltraPermutationRelation<FF>,
                                   bb::LogDerivLookupRelation<FF>,
@@ -97,6 +97,22 @@ class UltraFlavor {
     static constexpr size_t BATCHED_RELATION_PARTIAL_LENGTH = MAX_PARTIAL_RELATION_LENGTH + 1;
     static constexpr size_t NUM_RELATIONS = std::tuple_size_v<Relations>;
 
+    // Proof length formula:
+    // 1. HONK_PROOF_PUBLIC_INPUT_OFFSET are the circuit_size, num_public_inputs, pub_inputs_offset
+    // 2. PAIRING_POINT_ACCUMULATOR_SIZE public inputs for pairing point accumulator
+    // 3. NUM_WITNESS_ENTITIES commitments
+    // 4. CONST_PROOF_SIZE_LOG_N sumcheck univariates
+    // 5. NUM_ALL_ENTITIES sumcheck evaluations
+    // 6. CONST_PROOF_SIZE_LOG_N Gemini Fold commitments
+    // 7. CONST_PROOF_SIZE_LOG_N Gemini a evaluations
+    // 8. KZG W commitment
+    static constexpr size_t num_frs_comm = bb::field_conversion::calc_num_bn254_frs<Commitment>();
+    static constexpr size_t num_frs_fr = bb::field_conversion::calc_num_bn254_frs<FF>();
+    static constexpr size_t PROOF_LENGTH_WITHOUT_PUB_INPUTS =
+        HONK_PROOF_PUBLIC_INPUT_OFFSET + NUM_WITNESS_ENTITIES * num_frs_comm +
+        CONST_PROOF_SIZE_LOG_N * BATCHED_RELATION_PARTIAL_LENGTH * num_frs_fr + NUM_ALL_ENTITIES * num_frs_fr +
+        CONST_PROOF_SIZE_LOG_N * num_frs_comm + CONST_PROOF_SIZE_LOG_N * num_frs_fr + num_frs_comm;
+
     template <size_t NUM_KEYS>
     using ProtogalaxyTupleOfTuplesOfUnivariatesNoOptimisticSkipping =
         decltype(create_protogalaxy_tuple_of_tuples_of_univariates<Relations, NUM_KEYS>());
@@ -537,7 +553,6 @@ class UltraFlavor {
      * @brief A container for storing the partially evaluated multivariates produced by sumcheck.
      */
     class PartiallyEvaluatedMultivariates : public AllEntities<Polynomial> {
-
       public:
         PartiallyEvaluatedMultivariates() = default;
         PartiallyEvaluatedMultivariates(const size_t circuit_size)
@@ -675,7 +690,7 @@ class UltraFlavor {
                 this->z_perm = commitments.z_perm;
             }
         }
-    };
+    }; // namespace bb
     // Specialize for Ultra (general case used in UltraRecursive).
     using VerifierCommitments = VerifierCommitments_<Commitment, VerificationKey>;
 

barretenberg/cpp/src/barretenberg/stdlib_circuit_builders/ultra_rollup_flavor.hpp

@@ -1,10 +1,26 @@
 #pragma once
+#include "barretenberg/commitment_schemes/ipa/ipa.hpp"
 #include "barretenberg/stdlib_circuit_builders/ultra_flavor.hpp"
 
 namespace bb {
 
 class UltraRollupFlavor : public bb::UltraFlavor {
   public:
+    // Proof length formula:
+    // 1. HONK_PROOF_PUBLIC_INPUT_OFFSET are the circuit_size, num_public_inputs, pub_inputs_offset
+    // 2. PAIRING_POINT_ACCUMULATOR_SIZE public inputs for pairing point accumulator
+    // 3. IPA_CLAIM_SIZE public inputs for IPA claim
+    // 4. NUM_WITNESS_ENTITIES commitments
+    // 5. CONST_PROOF_SIZE_LOG_N sumcheck univariates
+    // 6. NUM_ALL_ENTITIES sumcheck evaluations
+    // 7. CONST_PROOF_SIZE_LOG_N Gemini Fold commitments
+    // 8. CONST_PROOF_SIZE_LOG_N Gemini a evaluations
+    // 9. KZG W commitment
+    static constexpr size_t num_frs_comm = bb::field_conversion::calc_num_bn254_frs<Commitment>();
+    static constexpr size_t num_frs_fr = bb::field_conversion::calc_num_bn254_frs<FF>();
+    static constexpr size_t PROOF_LENGTH_WITHOUT_PUB_INPUTS =
+        UltraFlavor::PROOF_LENGTH_WITHOUT_PUB_INPUTS + IPA_PROOF_LENGTH;
+
     using UltraFlavor::UltraFlavor;
     class ProvingKey : public UltraFlavor::ProvingKey {
       public:

barretenberg/cpp/src/barretenberg/ultra_honk/CMakeLists.txt

@@ -1 +1 @@
-barretenberg_module(ultra_honk sumcheck)
+barretenberg_module(ultra_honk sumcheck stdlib_primitives)

barretenberg/cpp/src/barretenberg/ultra_honk/ultra_prover.cpp

@@ -47,7 +47,7 @@ template <IsUltraFlavor Flavor> HonkProof UltraProver_<Flavor>::export_proof()
     // Add the IPA proof
     if constexpr (HasIPAAccumulator<Flavor>) {
         // The extra calculation is for the IPA proof length.
-        ASSERT(proving_key->proving_key.ipa_proof.size() == 1 + 4 * (CONST_ECCVM_LOG_N) + 2 + 2);
+        ASSERT(proving_key->proving_key.ipa_proof.size() == IPA_PROOF_LENGTH);
         proof.insert(proof.end(), proving_key->proving_key.ipa_proof.begin(), proving_key->proving_key.ipa_proof.end());
     }
     return proof;