Fix constant names. Add groth16_CalcPublicBufferSize function. Used i…

…t to
iden3 · Dec 27, 2023 · 83ee2f3 · 83ee2f3
1 parent f9e9974
commit 83ee2f3
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Showing 3 changed files with 44 additions and 24 deletions.
diff --git a/src/main_prover.cpp b/src/main_prover.cpp
@@ -26,29 +26,33 @@ int main(int argc, char **argv)
         std::string proofFilename = argv[3];
         std::string publicFilename = argv[4];
 
+        BinFileUtils::FileLoader zkeyFileLoader(zkeyFilename);
+        BinFileUtils::FileLoader wtnsFileLoader(wtnsFilename);
+
         char proofBuffer[BufferSize];
-        char publicBuffer[BufferSize];
+
+        size_t publicBufferSize = groth16_CalcPublicBufferSize(
+            zkeyFileLoader.dataBuffer(),
+            zkeyFileLoader.dataSize()
+        );
+
+        char publicBuffer[publicBufferSize];
+
         size_t proofSize  = sizeof(proofBuffer);
         size_t publicSize = sizeof(publicBuffer);
         char errorMessage[256];
         int error = 0;
 
-        BinFileUtils::FileLoader zkeyFileLoader(zkeyFilename);
-        BinFileUtils::FileLoader wtnsFileLoader(wtnsFilename);
-
         error = groth16_prover(zkeyFileLoader.dataBuffer(), zkeyFileLoader.dataSize(),
                                wtnsFileLoader.dataBuffer(), wtnsFileLoader.dataSize(),
                                proofBuffer,  &proofSize,
                                publicBuffer, &publicSize,
                                errorMessage, sizeof(errorMessage));
 
-        if (error == PPROVER_ERROR_SHORT_BUFFER) {
-
+        if (error == PROVER_ERROR_SHORT_BUFFER) {
             std::cerr << "Error: Short buffer for proof or public" << '\n';
             return EXIT_FAILURE;
-        }
-
-        else if (error) {
+        } else if (error) {
             std::cerr << errorMessage << '\n';
             return EXIT_FAILURE;
         }
@@ -66,7 +70,6 @@ int main(int argc, char **argv)
     } catch (std::exception* e) {
         std::cerr << e->what() << '\n';
         return EXIT_FAILURE;
-
     } catch (std::exception& e) {
         std::cerr << e.what() << '\n';
         return EXIT_FAILURE;

diff --git a/src/prover.cpp b/src/prover.cpp
@@ -16,12 +16,12 @@ using json = nlohmann::json;
 
 static size_t ProofBufferMinSize()
 {
-    return 726;
+    return 810;
 }
 
 static size_t PublicBufferMinSize(size_t count)
 {
-    return count * 81 + 3;
+    return count * 82 + 4;
 }
 
 static void VerifyPrimes(mpz_srcptr zkey_prime, mpz_srcptr wtns_prime)
@@ -54,6 +54,17 @@ std::string BuildPublicString(AltBn128::FrElement *wtnsData, size_t nPublic)
     return jsonPublic.dump();
 }
 
+unsigned long groth16_CalcPublicBufferSize(const void *zkey_buffer,   unsigned long  zkey_size) {
+    try {
+        BinFileUtils::BinFile zkey(zkey_buffer, zkey_size, "zkey", 1);
+        auto zkeyHeader = ZKeyUtils::loadHeader(&zkey);
+        return PublicBufferMinSize(zkeyHeader->nPublic);
+    } catch (...) {
+    }
+
+    return 0;
+}
+
 int
 groth16_prover(const void *zkey_buffer,   unsigned long  zkey_size,
                const void *wtns_buffer,   unsigned long  wtns_size,
@@ -76,7 +87,7 @@ groth16_prover(const void *zkey_buffer,   unsigned long  zkey_size,
             *proof_size  = proofMinSize;
             *public_size = publicMinSize;
 
-            return PPROVER_ERROR_SHORT_BUFFER;
+            return PROVER_ERROR_SHORT_BUFFER;
         }
 
         VerifyPrimes(zkeyHeader->rPrime, wtnsHeader->prime);
@@ -112,7 +123,7 @@ groth16_prover(const void *zkey_buffer,   unsigned long  zkey_size,
             *proof_size  = stringProofSize;
             *public_size = stringPublicSize;
 
-            return PPROVER_ERROR_SHORT_BUFFER;
+            return PROVER_ERROR_SHORT_BUFFER;
         }
 
         std::strncpy(proof_buffer, stringProof.data(), *proof_size);
@@ -123,22 +134,22 @@ groth16_prover(const void *zkey_buffer,   unsigned long  zkey_size,
         if (error_msg) {
             strncpy(error_msg, e.what(), error_msg_maxsize);
         }
-        return PPROVER_ERROR;
+        return PROVER_ERROR;
 
     } catch (std::exception *e) {
 
         if (error_msg) {
             strncpy(error_msg, e->what(), error_msg_maxsize);
         }
         delete e;
-        return PPROVER_ERROR;
+        return PROVER_ERROR;
 
     } catch (...) {
         if (error_msg) {
             strncpy(error_msg, "unknown error", error_msg_maxsize);
         }
-        return PPROVER_ERROR;
+        return PROVER_ERROR;
     }
 
-    return PRPOVER_OK;
+    return PROVER_OK;
 }
diff --git a/src/prover.h b/src/prover.h
@@ -6,17 +6,23 @@ extern "C" {
 #endif
 
 //Error codes returned by the functions.
-#define PRPOVER_OK                  0x0
-#define PPROVER_ERROR               0x1
-#define PPROVER_ERROR_SHORT_BUFFER  0x2
+#define PROVER_OK                  0x0
+#define PROVER_ERROR               0x1
+#define PROVER_ERROR_SHORT_BUFFER  0x2
 
+/**
+ * Calculates buffer size to output public signals as json string
+ * @returns buffer size in bytes or 0 in case of an error
+ */
+unsigned long groth16_CalcPublicBufferSize(const void *zkey_buffer,   unsigned long  zkey_size);
 
 /**
+ * groth16_prover
  * @return error code:
- *         PRPOVER_OK - in case of success.
- *         PPROVER_ERROR - in case of an error.
+ *         PROVER_OK - in case of success
+ *         PPOVER_ERROR - in case of an error
+ *         PROVER_ERROR_SHORT_BUFFER - in case of a short buffer error, also updates proof_size and public_size with actual proof and public sizess
  */
-
 int
 groth16_prover(const void *zkey_buffer,   unsigned long  zkey_size,
                const void *wtns_buffer,   unsigned long  wtns_size,