Isolate verification to a ProofVerifier context object that allows verification behavior to be tuned by the caller.

src/zcash/JoinSplit.cpp

@@ -5,7 +5,6 @@
 #include "zcash/util.h"
 
 #include <memory>
-#include <mutex>
 
 #include <boost/foreach.hpp>
 #include <boost/format.hpp>
@@ -25,8 +24,6 @@ namespace libzcash {
 
 #include "zcash/circuit/gadget.tcc"
 
-std::once_flag init_public_params_once_flag;
-
 CCriticalSection cs_ParamsIO;
 CCriticalSection cs_LoadKeys;
 
@@ -80,10 +77,6 @@ public:
     JoinSplitCircuit() {}
     ~JoinSplitCircuit() {}
 
-    static void initialize() {
-        std::call_once (init_public_params_once_flag, ppzksnark_ppT::init_public_params);
-    }
-
     void setProvingKeyPath(std::string path) {
         pkPath = path;
     }
@@ -151,6 +144,7 @@ public:
 
     bool verify(
         const ZCProof& proof,
+        ProofVerifier& verifier,
         const uint256& pubKeyHash,
         const uint256& randomSeed,
         const boost::array<uint256, NumInputs>& macs,
@@ -179,7 +173,12 @@ public:
                 vpub_new
             );
 
-            return r1cs_ppzksnark_online_verifier_strong_IC<ppzksnark_ppT>(*vk_precomp, witness, r1cs_proof);
+            return verifier.check(
+                *vk,
+                *vk_precomp,
+                witness,
+                r1cs_proof
+            );
         } catch (...) {
             return false;
         }
@@ -358,7 +357,7 @@ public:
 template<size_t NumInputs, size_t NumOutputs>
 JoinSplit<NumInputs, NumOutputs>* JoinSplit<NumInputs, NumOutputs>::Generate()
 {
-    JoinSplitCircuit<NumInputs, NumOutputs>::initialize();
+    initialize_curve_params();
     auto js = new JoinSplitCircuit<NumInputs, NumOutputs>();
     js->generate();
 
@@ -368,7 +367,7 @@ JoinSplit<NumInputs, NumOutputs>* JoinSplit<NumInputs, NumOutputs>::Generate()
 template<size_t NumInputs, size_t NumOutputs>
 JoinSplit<NumInputs, NumOutputs>* JoinSplit<NumInputs, NumOutputs>::Unopened()
 {
-    JoinSplitCircuit<NumInputs, NumOutputs>::initialize();
+    initialize_curve_params();
     return new JoinSplitCircuit<NumInputs, NumOutputs>();
 }
 

src/zcash/JoinSplit.hpp

@@ -83,6 +83,7 @@ public:
 
     virtual bool verify(
         const ZCProof& proof,
+        ProofVerifier& verifier,
         const uint256& pubKeyHash,
         const uint256& randomSeed,
         const boost::array<uint256, NumInputs>& hmacs,

src/zcash/Proof.cpp

@@ -1,6 +1,7 @@
 #include "Proof.hpp"
 
 #include <boost/static_assert.hpp>
+#include <mutex>
 
 #include "crypto/common.h"
 #include "libsnark/common/default_types/r1cs_ppzksnark_pp.hpp"
@@ -211,4 +212,36 @@ ZCProof ZCProof::random_invalid()
     return p;
 }
 
+std::once_flag init_public_params_once_flag;
+
+void initialize_curve_params()
+{
+    std::call_once (init_public_params_once_flag, curve_pp::init_public_params);
+}
+
+ProofVerifier ProofVerifier::Strict() {
+    initialize_curve_params();
+    return ProofVerifier(true);
+}
+
+ProofVerifier ProofVerifier::Dummy() {
+    initialize_curve_params();
+    return ProofVerifier(false);
+}
+
+template<>
+bool ProofVerifier::check(
+    const r1cs_ppzksnark_verification_key<curve_pp>& vk,
+    const r1cs_ppzksnark_processed_verification_key<curve_pp>& pvk,
+    const r1cs_primary_input<curve_Fr>& primary_input,
+    const r1cs_ppzksnark_proof<curve_pp>& proof
+)
+{
+    if (perform_verification) {
+        return r1cs_ppzksnark_online_verifier_strong_IC<curve_pp>(pvk, primary_input, proof);
+    } else {
+        return true;
+    }
+}
+
 }

src/zcash/Proof.hpp

@@ -235,6 +235,36 @@ public:
     }
 };
 
+void initialize_curve_params();
+
+class ProofVerifier {
+private:
+    bool perform_verification;
+
+    ProofVerifier(bool perform_verification) : perform_verification(perform_verification) { }
+
+public:
+    // Creates a verification context that strictly verifies
+    // all proofs using libsnark's API.
+    static ProofVerifier Strict();
+
+    // Creates a dummy verification context that performs
+    // no verification, used when avoiding duplicate effort
+    // such as during reindexing.
+    static ProofVerifier Dummy();
+
+    template <typename VerificationKey,
+              typename ProcessedVerificationKey,
+              typename PrimaryInput,
+              typename Proof
+              >
+    bool check(
+        const VerificationKey& vk,
+        const ProcessedVerificationKey& pvk,
+        const PrimaryInput& pi,
+        const Proof& p
+    );
+};
 
 }