chore: civc tidy 3

barretenberg/cpp/src/barretenberg/api/api_client_ivc.cpp

@@ -130,7 +130,8 @@ bool ClientIVCAPI::prove_and_verify(const std::filesystem::path& input_path)
     std::shared_ptr<ClientIVC> ivc = steps.accumulate();
     // Construct the hiding kernel as the final step of the IVC
 
-    const bool verified = ivc->prove_and_verify();
+    auto proof = ivc->prove();
+    const bool verified = ClientIVC::verify(proof, ivc->get_vk());
     return verified;
 }
 

barretenberg/cpp/src/barretenberg/bbapi/bbapi_client_ivc.cpp

@@ -86,7 +86,8 @@ ClientIvcProve::Response ClientIvcProve::execute(BBApiRequest& request) &&
     // We verify this proof. Another bb call to verify has some overhead of loading VK/proof/SRS,
     // and it is mysterious if this transaction fails later in the lifecycle.
     info("ClientIvcProve - verifying the generated proof as a sanity check");
-    if (!request.ivc_in_progress->verify(proof)) {
+    ClientIVC::VerificationKey vk = request.ivc_in_progress->get_vk();
+    if (!ClientIVC::verify(proof, vk)) {
         throw_or_abort("Failed to verify the generated proof!");
     }
 

barretenberg/cpp/src/barretenberg/client_ivc/client_ivc.cpp

@@ -172,8 +172,6 @@ ClientIVC::perform_recursive_verification_and_databus_consistency_checks(
     }
     case QUEUE_TYPE::PG:
     case QUEUE_TYPE::PG_TAIL: {
-        BB_ASSERT_NEQ(input_verifier_accumulator, nullptr);
-
         output_verifier_accumulator = perform_pg_recursive_verification(circuit,
                                                                         input_verifier_accumulator,
                                                                         verifier_instance,
@@ -184,18 +182,10 @@ ClientIVC::perform_recursive_verification_and_databus_consistency_checks(
         break;
     }
     case QUEUE_TYPE::PG_FINAL: {
-        BB_ASSERT_NEQ(input_verifier_accumulator, nullptr);
         BB_ASSERT_EQ(stdlib_verification_queue.size(), size_t(1));
 
         hide_op_queue_accumulation_result(circuit);
 
-        // Propagate the public inputs of the tail kernel by converting them to public inputs of the hiding circuit.
-        auto num_public_inputs = static_cast<size_t>(honk_vk->num_public_inputs);
-        num_public_inputs -= KernelIO::PUBLIC_INPUTS_SIZE; // exclude fixed kernel_io public inputs
-        for (size_t i = 0; i < num_public_inputs; i++) {
-            verifier_inputs.proof[i].set_public();
-        }
-
         auto final_verifier_accumulator = perform_pg_recursive_verification(circuit,
                                                                             input_verifier_accumulator,
                                                                             verifier_instance,
@@ -245,7 +235,7 @@ ClientIVC::perform_recursive_verification_and_databus_consistency_checks(
         kernel_input.output_pg_accum_hash.assert_equal(*prev_accum_hash);
 
         if (!is_hiding_kernel) {
-            // The hiding kernel has no return data but uses the traditional public-inputs mechanism
+            // The hiding kernel has no return data; it uses the traditional public-inputs mechanism
             bus_depot.set_kernel_return_data_commitment(witness_commitments.return_data);
         }
     } else {
@@ -384,7 +374,7 @@ HonkProof ClientIVC::construct_oink_proof(const std::shared_ptr<DeciderProvingKe
     proving_key->gate_challenges =
         prover_accumulation_transcript->template get_powers_of_challenge<FF>("gate_challenge", CONST_PG_LOG_N);
 
-    fold_output.accumulator = proving_key; // initialize the prover accum with the completed key
+    prover_accumulator = proving_key; // initialize the prover accum with the completed key
 
     HonkProof oink_proof = oink_prover.export_proof();
     vinfo("oink proof constructed");
@@ -406,13 +396,14 @@ HonkProof ClientIVC::construct_pg_proof(const std::shared_ptr<DeciderProvingKey>
         info("Accumulator hash in PG prover: ", accum_hash);
     }
     auto verifier_instance = std::make_shared<DeciderVerificationKey_<Flavor>>(honk_vk);
-    FoldingProver folding_prover({ fold_output.accumulator, proving_key },
+    FoldingProver folding_prover({ prover_accumulator, proving_key },
                                  { native_verifier_accum, verifier_instance },
                                  transcript,
                                  trace_usage_tracker);
-    fold_output = folding_prover.prove();
+    auto output = folding_prover.prove();
+    prover_accumulator = output.accumulator; // update the prover accumulator
     vinfo("pg proof constructed");
-    return fold_output.proof;
+    return output.proof;
 }
 
 /**
@@ -472,8 +463,6 @@ void ClientIVC::accumulate(ClientCircuit& circuit, const std::shared_ptr<MegaVer
     proving_key->commitment_key = bn254_commitment_key;
     trace_usage_tracker.update(circuit);
 
-    honk_vk = precomputed_vk;
-
     // We're accumulating a kernel if the verification queue is empty (because the kernel circuit contains recursive
     // verifiers for all the entries previously present in the verification queue) and if it's not the first accumulate
     // call (which will always be for an app circuit).
@@ -495,22 +484,22 @@ void ClientIVC::accumulate(ClientCircuit& circuit, const std::shared_ptr<MegaVer
     case QUEUE_TYPE::OINK:
         vinfo("Accumulating first app circuit with OINK");
         BB_ASSERT_EQ(is_kernel, false, "First circuit accumulated must always be an app");
-        proof = construct_oink_proof(proving_key, honk_vk, prover_accumulation_transcript);
+        proof = construct_oink_proof(proving_key, precomputed_vk, prover_accumulation_transcript);
         break;
     case QUEUE_TYPE::PG:
     case QUEUE_TYPE::PG_TAIL:
-        proof = construct_pg_proof(proving_key, honk_vk, prover_accumulation_transcript, is_kernel);
+        proof = construct_pg_proof(proving_key, precomputed_vk, prover_accumulation_transcript, is_kernel);
         break;
     case QUEUE_TYPE::PG_FINAL:
-        proof = construct_pg_proof(proving_key, honk_vk, prover_accumulation_transcript, is_kernel);
+        proof = construct_pg_proof(proving_key, precomputed_vk, prover_accumulation_transcript, is_kernel);
         decider_proof = construct_decider_proof(prover_accumulation_transcript);
         break;
     case QUEUE_TYPE::MEGA:
-        proof = construct_mega_proof_for_hiding_kernel(circuit);
+        proof = construct_honk_proof_for_hiding_kernel(circuit, precomputed_vk);
         break;
     }
 
-    VerifierInputs queue_entry{ std::move(proof), honk_vk, queue_type, is_kernel };
+    VerifierInputs queue_entry{ std::move(proof), precomputed_vk, queue_type, is_kernel };
     verification_queue.push_back(queue_entry);
 
     // Update native verifier accumulator and construct merge proof (excluded for hiding kernel since PG terminates with
@@ -612,14 +601,14 @@ void ClientIVC::hide_op_queue_content_in_hiding(ClientCircuit& circuit)
  * @brief Construct a zero-knowledge proof for the hiding circuit, which recursively verifies the last folding,
  * merge and decider proof.
  */
-HonkProof ClientIVC::construct_mega_proof_for_hiding_kernel(ClientCircuit& circuit)
+HonkProof ClientIVC::construct_honk_proof_for_hiding_kernel(
+    ClientCircuit& circuit, const std::shared_ptr<MegaVerificationKey>& verification_key)
 {
     // Note: a structured trace is not used for the hiding kernel
     auto hiding_decider_pk = std::make_shared<DeciderZKProvingKey>(circuit, TraceSettings(), bn254_commitment_key);
-    honk_vk = std::make_shared<MegaZKVerificationKey>(hiding_decider_pk->get_precomputed());
-    auto& hiding_circuit_vk = honk_vk;
+
     // Hiding circuit is proven by a MegaZKProver
-    MegaZKProver prover(hiding_decider_pk, hiding_circuit_vk, transcript);
+    MegaZKProver prover(hiding_decider_pk, verification_key, transcript);
     HonkProof proof = prover.construct_proof();
 
     return proof;
@@ -633,7 +622,7 @@ HonkProof ClientIVC::construct_mega_proof_for_hiding_kernel(ClientCircuit& circu
 ClientIVC::Proof ClientIVC::prove()
 {
     // deallocate the protogalaxy accumulator
-    fold_output.accumulator = nullptr;
+    prover_accumulator = nullptr;
     auto mega_proof = verification_queue.front().proof;
 
     // A transcript is shared between the Hiding circuit prover and the Goblin prover
@@ -669,17 +658,6 @@ bool ClientIVC::verify(const Proof& proof, const VerificationKey& vk)
     return goblin_verified && mega_verified;
 }
 
-/**
- * @brief Verify a full proof of the IVC
- *
- * @param proof
- * @return bool
- */
-bool ClientIVC::verify(const Proof& proof) const
-{
-    return verify(proof, get_vk());
-}
-
 /**
  * @brief Internal method for constructing a decider proof
  *
@@ -688,36 +666,12 @@ bool ClientIVC::verify(const Proof& proof) const
 HonkProof ClientIVC::construct_decider_proof(const std::shared_ptr<Transcript>& transcript)
 {
     vinfo("prove decider...");
-    fold_output.accumulator->commitment_key = bn254_commitment_key;
-    MegaDeciderProver decider_prover(fold_output.accumulator, transcript);
+    prover_accumulator->commitment_key = bn254_commitment_key;
+    MegaDeciderProver decider_prover(prover_accumulator, transcript);
     decider_prover.construct_proof();
     return decider_prover.export_proof();
 }
 
-/**
- * @brief Construct and verify a proof for the IVC
- * @note Use of this method only makes sense when the prover and verifier are the same entity, e.g. in
- * development/testing.
- *
- */
-bool ClientIVC::prove_and_verify()
-{
-    auto start = std::chrono::steady_clock::now();
-    const auto proof = prove();
-    auto end = std::chrono::steady_clock::now();
-    auto diff = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
-    vinfo("time to call ClientIVC::prove: ", diff.count(), " ms.");
-
-    start = end;
-    const bool verified = verify(proof);
-    end = std::chrono::steady_clock::now();
-
-    diff = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
-    vinfo("time to verify ClientIVC proof: ", diff.count(), " ms.");
-
-    return verified;
-}
-
 // Proof methods
 size_t ClientIVC::Proof::size() const
 {
@@ -842,7 +796,12 @@ ClientIVC::Proof ClientIVC::Proof::from_file_msgpack(const std::string& filename
 // VerificationKey construction
 ClientIVC::VerificationKey ClientIVC::get_vk() const
 {
-    return { honk_vk, std::make_shared<ECCVMVerificationKey>(), std::make_shared<TranslatorVerificationKey>() };
+    BB_ASSERT_EQ(verification_queue.size(), 1UL);
+    BB_ASSERT_EQ(verification_queue.front().type == QUEUE_TYPE::MEGA, true);
+    auto verification_key = verification_queue.front().honk_vk;
+    return { verification_key,
+             std::make_shared<ECCVMVerificationKey>(),
+             std::make_shared<TranslatorVerificationKey>() };
 }
 
 void ClientIVC::update_native_verifier_accumulator(const VerifierInputs& queue_entry,

barretenberg/cpp/src/barretenberg/client_ivc/client_ivc.hpp

@@ -257,8 +257,6 @@ class ClientIVC {
     ExecutionTraceUsageTracker trace_usage_tracker;
 
   private:
-    using ProverFoldOutput = FoldingResult<Flavor>;
-
     // Transcript for CIVC prover (shared between Hiding circuit, Merge, ECCVM, and Translator)
     std::shared_ptr<Transcript> transcript = std::make_shared<Transcript>();
 
@@ -269,14 +267,13 @@ class ClientIVC {
   public:
     size_t num_circuits_accumulated = 0; // number of circuits accumulated so far
 
-    ProverFoldOutput fold_output; // prover accumulator and fold proof
-    HonkProof decider_proof;      // decider proof to be verified in the hiding circuit
+    std::shared_ptr<DeciderProvingKey> prover_accumulator; // current PG prover accumulator instance
+    HonkProof decider_proof;                               // decider proof to be verified in the hiding circuit
 
     std::shared_ptr<DeciderVerificationKey>
         recursive_verifier_native_accum; // native verifier accumulator used in recursive folding
     std::shared_ptr<DeciderVerificationKey>
-        native_verifier_accum;                    //  native verifier accumulator used in prover folding
-    std::shared_ptr<MegaVerificationKey> honk_vk; // honk vk to be completed and folded into the accumulator
+        native_verifier_accum; //  native verifier accumulator used in prover folding
 
     // Set of tuples {proof, verification_key, type (Oink/PG)} to be recursively verified
     VerificationQueue verification_queue;
@@ -327,14 +324,9 @@ class ClientIVC {
     static void hide_op_queue_accumulation_result(ClientCircuit& circuit);
     static void hide_op_queue_content_in_tail(ClientCircuit& circuit);
     static void hide_op_queue_content_in_hiding(ClientCircuit& circuit);
-    HonkProof construct_mega_proof_for_hiding_kernel(ClientCircuit& circuit);
 
     static bool verify(const Proof& proof, const VerificationKey& vk);
 
-    bool verify(const Proof& proof) const;
-
-    bool prove_and_verify();
-
     HonkProof construct_decider_proof(const std::shared_ptr<Transcript>& transcript);
 
     VerificationKey get_vk() const;
@@ -358,6 +350,9 @@ class ClientIVC {
                                  const std::shared_ptr<Transcript>& transcript,
                                  bool is_kernel);
 
+    HonkProof construct_honk_proof_for_hiding_kernel(ClientCircuit& circuit,
+                                                     const std::shared_ptr<MegaVerificationKey>& verification_key);
+
     QUEUE_TYPE get_queue_type() const;
 
     static std::shared_ptr<RecursiveDeciderVerificationKey> perform_oink_recursive_verification(

barretenberg/cpp/src/barretenberg/client_ivc/client_ivc.test.cpp

@@ -67,10 +67,6 @@ class ClientIVCTests : public ::testing::Test {
         ClientIVC ivc{ num_circuits, trace_settings };
 
         for (size_t j = 0; j < num_circuits; ++j) {
-            // Use default test settings for the mock hiding kernel since it's size must always be consistent
-            if (j == num_circuits - 1) {
-                settings = TestSettings{};
-            }
             circuit_producer.construct_and_accumulate_next_circuit(ivc, settings);
         }
         return { ivc.prove(), ivc.get_vk() };
@@ -112,7 +108,8 @@ TEST_F(ClientIVCTests, BadProofFailure)
         for (size_t idx = 0; idx < NUM_CIRCUITS; ++idx) {
             circuit_producer.construct_and_accumulate_next_circuit(ivc, settings);
         }
-        EXPECT_TRUE(ivc.prove_and_verify());
+        auto proof = ivc.prove();
+        EXPECT_TRUE(ClientIVC::verify(proof, ivc.get_vk()));
     }
 
     // The IVC throws an exception if the FIRST fold proof is tampered with
@@ -139,7 +136,8 @@ TEST_F(ClientIVCTests, BadProofFailure)
                                   num_public_inputs); // tamper with first proof
             }
         }
-        EXPECT_FALSE(ivc.prove_and_verify());
+        auto proof = ivc.prove();
+        EXPECT_FALSE(ClientIVC::verify(proof, ivc.get_vk()));
     }
 
     // The IVC fails if the SECOND fold proof is tampered with
@@ -160,7 +158,8 @@ TEST_F(ClientIVCTests, BadProofFailure)
                                   circuit.num_public_inputs()); // tamper with second proof
             }
         }
-        EXPECT_FALSE(ivc.prove_and_verify());
+        auto proof = ivc.prove();
+        EXPECT_FALSE(ClientIVC::verify(proof, ivc.get_vk()));
     }
 
     EXPECT_TRUE(true);
@@ -313,7 +312,8 @@ TEST_F(ClientIVCTests, StructuredTraceOverflow)
         log2_num_gates += 1;
     }
 
-    EXPECT_TRUE(ivc.prove_and_verify());
+    auto proof = ivc.prove();
+    EXPECT_TRUE(ClientIVC::verify(proof, ivc.get_vk()));
 };
 
 /**
@@ -348,8 +348,9 @@ TEST_F(ClientIVCTests, DynamicTraceOverflow)
                 ivc, { .log2_num_gates = test.log2_num_arith_gates[idx] });
         }
 
-        EXPECT_EQ(check_accumulator_target_sum_manual(ivc.fold_output.accumulator), true);
-        EXPECT_TRUE(ivc.prove_and_verify());
+        EXPECT_EQ(check_accumulator_target_sum_manual(ivc.prover_accumulator), true);
+        auto proof = ivc.prove();
+        EXPECT_TRUE(ClientIVC::verify(proof, ivc.get_vk()));
     }
 }
 
@@ -421,5 +422,6 @@ TEST_F(ClientIVCTests, DatabusFailure)
         ivc.accumulate(circuit, vk);
     }
 
-    EXPECT_FALSE(ivc.prove_and_verify());
+    auto proof = ivc.prove();
+    EXPECT_FALSE(ClientIVC::verify(proof, ivc.get_vk()));
 };

barretenberg/cpp/src/barretenberg/client_ivc/mock_circuit_producer.hpp

@@ -202,6 +202,11 @@ class PrivateFunctionExecutionMockCircuitProducer {
     std::pair<ClientCircuit, std::shared_ptr<VerificationKey>> create_next_circuit_and_vk(ClientIVC& ivc,
                                                                                           TestSettings settings = {})
     {
+        // If this is a mock hiding kernel, remove the settings and use a default (non-structured) trace
+        if (ivc.num_circuits_accumulated == ivc.get_num_circuits() - 1) {
+            settings = TestSettings{};
+            ivc.trace_settings = TraceSettings{};
+        }
         auto circuit = create_next_circuit(ivc, settings.log2_num_gates, settings.num_public_inputs);
         return { circuit, get_verification_key(circuit, ivc.trace_settings) };
     }

barretenberg/cpp/src/barretenberg/client_ivc/mock_kernel_pinning.test.cpp

@@ -32,8 +32,12 @@ TEST_F(MockKernelTest, PinFoldingKernelSizes)
         auto [circuit, vk] = circuit_producer.create_next_circuit_and_vk(ivc);
 
         ivc.accumulate(circuit, vk);
-        EXPECT_TRUE(circuit.blocks.has_overflow); // trace overflow mechanism should be triggered
+        // Expect trace overflow for all but the hiding kernel (final circuit)
+        if (idx < NUM_CIRCUITS - 1) {
+            EXPECT_TRUE(circuit.blocks.has_overflow);
+            EXPECT_EQ(ivc.prover_accumulator->log_dyadic_size(), 19);
+        } else {
+            EXPECT_FALSE(circuit.blocks.has_overflow);
+        }
     }
-
-    EXPECT_EQ(ivc.fold_output.accumulator->log_dyadic_size(), 19);
 }

barretenberg/cpp/src/barretenberg/client_ivc/test_bench_shared.hpp

@@ -13,23 +13,6 @@
 
 namespace bb {
 
-/**
- * @brief Verify an IVC proof
- *
- */
-bool verify_ivc(ClientIVC::Proof& proof, ClientIVC& ivc)
-{
-    bool verified = ivc.verify(proof);
-
-    // This is a benchmark, not a test, so just print success or failure to the log
-    if (verified) {
-        info("IVC successfully verified!");
-    } else {
-        info("IVC failed to verify.");
-    }
-    return verified;
-}
-
 /**
  * @brief Perform a specified number of circuit accumulation rounds
  *