diff --git a/src/main_prover.cpp b/src/main_prover.cpp
index 18a56be..997dc76 100644
--- a/src/main_prover.cpp
+++ b/src/main_prover.cpp
@@ -1,17 +1,21 @@
 #include <iostream>
 #include <fstream>
+#include <gmp.h>
+#include <memory>
 #include <stdexcept>
+#include <nlohmann/json.hpp>
 
-#include "fileloader.hpp"
-#include "prover.h"
+#include <alt_bn128.hpp>
+#include "binfile_utils.hpp"
+#include "zkey_utils.hpp"
+#include "wtns_utils.hpp"
+#include "groth16.hpp"
+
+using json = nlohmann::json;
 
 #define handle_error(msg) \
            do { perror(msg); exit(EXIT_FAILURE); } while (0)
 
-
-const size_t BufferSize = 32768;
-
-
 int main(int argc, char **argv)
 {
     if (argc != 5) {
@@ -20,60 +24,80 @@ int main(int argc, char **argv)
         return EXIT_FAILURE;
     }
 
+    mpz_t altBbn128r;
+
+    mpz_init(altBbn128r);
+    mpz_set_str(altBbn128r, "21888242871839275222246405745257275088548364400416034343698204186575808495617", 10);
+
     try {
         std::string zkeyFilename = argv[1];
         std::string wtnsFilename = argv[2];
         std::string proofFilename = argv[3];
         std::string publicFilename = argv[4];
 
-        BinFileUtils::FileLoader zkeyFileLoader(zkeyFilename);
-        BinFileUtils::FileLoader wtnsFileLoader(wtnsFilename);
+        auto zkey = BinFileUtils::openExisting(zkeyFilename, "zkey", 1);
+        auto zkeyHeader = ZKeyUtils::loadHeader(zkey.get());
 
-        char proofBuffer[BufferSize];
+        std::string proofStr;
+        if (mpz_cmp(zkeyHeader->rPrime, altBbn128r) != 0) {
+            throw std::invalid_argument( "zkey curve not supported" );
+        }
 
-        size_t publicBufferSize = groth16_CalcPublicBufferSize(
-            zkeyFileLoader.dataBuffer(),
-            zkeyFileLoader.dataSize()
-        );
+        auto wtns = BinFileUtils::openExisting(wtnsFilename, "wtns", 2);
+        auto wtnsHeader = WtnsUtils::loadHeader(wtns.get());
 
-        char publicBuffer[publicBufferSize];
-
-        size_t proofSize  = sizeof(proofBuffer);
-        size_t publicSize = sizeof(publicBuffer);
-        char errorMessage[256];
-        int error = 0;
-
-        error = groth16_prover(zkeyFileLoader.dataBuffer(), zkeyFileLoader.dataSize(),
-                               wtnsFileLoader.dataBuffer(), wtnsFileLoader.dataSize(),
-                               proofBuffer,  &proofSize,
-                               publicBuffer, &publicSize,
-                               errorMessage, sizeof(errorMessage));
-
-        if (error == PROVER_ERROR_SHORT_BUFFER) {
-            std::cerr << "Error: Short buffer for proof or public" << '\n';
-            return EXIT_FAILURE;
-        } else if (error) {
-            std::cerr << errorMessage << '\n';
-            return EXIT_FAILURE;
+        if (mpz_cmp(wtnsHeader->prime, altBbn128r) != 0) {
+            throw std::invalid_argument( "different wtns curve" );
         }
 
+        auto prover = Groth16::makeProver<AltBn128::Engine>(
+            zkeyHeader->nVars,
+            zkeyHeader->nPublic,
+            zkeyHeader->domainSize,
+            zkeyHeader->nCoefs,
+            zkeyHeader->vk_alpha1,
+            zkeyHeader->vk_beta1,
+            zkeyHeader->vk_beta2,
+            zkeyHeader->vk_delta1,
+            zkeyHeader->vk_delta2,
+            zkey->getSectionData(4),    // Coefs
+            zkey->getSectionData(5),    // pointsA
+            zkey->getSectionData(6),    // pointsB1
+            zkey->getSectionData(7),    // pointsB2
+            zkey->getSectionData(8),    // pointsC
+            zkey->getSectionData(9)     // pointsH1
+        );
+        AltBn128::FrElement *wtnsData = (AltBn128::FrElement *)wtns->getSectionData(2);
+        auto proof = prover->prove(wtnsData);
+
         std::ofstream proofFile;
         proofFile.open (proofFilename);
-        proofFile << proofBuffer;
+        proofFile << proof->toJson();
         proofFile.close();
 
         std::ofstream publicFile;
         publicFile.open (publicFilename);
-        publicFile << publicBuffer;
+
+        json jsonPublic;
+        AltBn128::FrElement aux;
+        for (int i=1; i<=zkeyHeader->nPublic; i++) {
+            AltBn128::Fr.toMontgomery(aux, wtnsData[i]);
+            jsonPublic.push_back(AltBn128::Fr.toString(aux));
+        }
+
+        publicFile << jsonPublic;
         publicFile.close();
 
     } catch (std::exception* e) {
+        mpz_clear(altBbn128r);
         std::cerr << e->what() << '\n';
         return EXIT_FAILURE;
     } catch (std::exception& e) {
+        mpz_clear(altBbn128r);
         std::cerr << e.what() << '\n';
         return EXIT_FAILURE;
     }
 
+    mpz_clear(altBbn128r);
     exit(EXIT_SUCCESS);
 }
diff --git a/src/prover.cpp b/src/prover.cpp
index 4adf4bc..4c3fee0 100644
--- a/src/prover.cpp
+++ b/src/prover.cpp
@@ -54,7 +54,7 @@ std::string BuildPublicString(AltBn128::FrElement *wtnsData, size_t nPublic)
     return jsonPublic.dump();
 }
 
-unsigned long groth16_CalcPublicBufferSize(const void *zkey_buffer,   unsigned long  zkey_size) {
+unsigned long CalcPublicBufferSize(const void *zkey_buffer, unsigned long zkey_size) {
     try {
         BinFileUtils::BinFile zkey(zkey_buffer, zkey_size, "zkey", 1);
         auto zkeyHeader = ZKeyUtils::loadHeader(&zkey);
diff --git a/src/prover.h b/src/prover.h
index f71f0d0..79d55f0 100644
--- a/src/prover.h
+++ b/src/prover.h
@@ -15,7 +15,7 @@ extern "C" {
  * 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);
+unsigned long CalcPublicBufferSize(const void *zkey_buffer, unsigned long zkey_size);
 
 /**
  * groth16_prover