add gadget files

Author: sammayo

.gitignore

@@ -1,7 +1,2 @@
-test
-*.o
-*.d
-depinst
-depsrc
 *~
 build

src/CMakeLists.txt

@@ -1,17 +1,36 @@
 include_directories(.)
 
 add_executable(
-  main
+  test
 
   test.cpp
 )
 target_link_libraries(
-  main
+  test
 
   snark
 )
 target_include_directories(
-  main
+  test
+
+  PUBLIC
+  ${DEPENDS_DIR}/libsnark
+  ${DEPENDS_DIR}/libsnark/depends/libfqfft
+  ${DEPENDS_DIR}/libsnark/depends/libff
+)
+
+add_executable(
+  test-gadget
+
+  test-gadget.cpp
+)
+target_link_libraries(
+  test-gadget
+
+  snark
+)
+target_include_directories(
+  test-gadget
 
   PUBLIC
   ${DEPENDS_DIR}/libsnark

src/gadget.hpp

@@ -0,0 +1,49 @@
+#include "libsnark/gadgetlib1/gadget.hpp"
+
+using namespace libsnark;
+
+template<typename FieldT>
+class test_gadget : public gadget<FieldT> {
+private:
+    pb_variable<FieldT> sym_1;
+    pb_variable<FieldT> y;
+    pb_variable<FieldT> sym_2;
+public:
+	const pb_variable<FieldT> out;
+    const pb_variable<FieldT> x;
+
+	test_gadget(protoboard<FieldT> &pb,
+				const pb_variable<FieldT> &out,
+				const pb_variable<FieldT> &x) : 
+				gadget<FieldT>(pb, "poly_gadget"), out(out), x(x)
+	{
+		// Allocate variables to protoboard
+	  	// The strings (like "x") are only for debugging purposes
+	  
+	  	sym_1.allocate(this->pb, "sym_1");
+    	y.allocate(this->pb, "y");
+		sym_2.allocate(this->pb, "sym_2");
+	}
+
+	void generate_r1cs_constraints()
+	{
+	  // x*x = sym_1
+	  this->pb.add_r1cs_constraint(r1cs_constraint<FieldT>(x, x, sym_1));
+
+	  // sym_1 * x = y
+	  this->pb.add_r1cs_constraint(r1cs_constraint<FieldT>(sym_1, x, y));
+
+	  // y + x = sym_2
+	  this->pb.add_r1cs_constraint(r1cs_constraint<FieldT>(y + x, 1, sym_2));
+
+	  // sym_2 + 5 = ~out
+	  this->pb.add_r1cs_constraint(r1cs_constraint<FieldT>(sym_2 + 5, 1, out));
+	}
+
+	void generate_r1cs_witness()
+	{
+		this->pb.val(sym_1) = this->pb.val(x) * this->pb.val(x);
+  		this->pb.val(y) = this->pb.val(sym_1) * this->pb.val(x);
+  		this->pb.val(sym_2) = this->pb.val(y) + this->pb.val(x);
+	}
+};

src/test-gadget.cpp

@@ -0,0 +1,76 @@
+#include <stdlib.h>
+#include <iostream>
+
+#include "libff/algebra/fields/field_utils.hpp"
+#include "libsnark/zk_proof_systems/ppzksnark/r1cs_ppzksnark/r1cs_ppzksnark.hpp"
+#include "libsnark/common/default_types/r1cs_ppzksnark_pp.hpp"
+#include "libsnark/gadgetlib1/pb_variable.hpp"
+
+#include "gadget.hpp"
+
+using namespace libsnark;
+using namespace std;
+
+int main()
+{
+  // Initialize the curve parameters.
+  default_r1cs_ppzksnark_pp::init_public_params();
+
+  typedef libff::Fr<default_r1cs_ppzksnark_pp> FieldT;
+  
+  // Create protoboard
+
+  protoboard<FieldT> pb;
+  pb_variable<FieldT> out;
+  pb_variable<FieldT> x;
+
+  // Allocate variables
+
+  out.allocate(pb, "out");
+  x.allocate(pb, "x");
+
+  // This sets up the protoboard variables
+  // so that the first one (out) represents the public
+  // input and the rest is private input
+
+  pb.set_input_sizes(1);
+
+  test_gadget<FieldT> g(pb, out, x);
+  g.generate_r1cs_constraints();
+
+  cout << "Number of variables: " << pb.num_variables() << endl;
+  
+  // Add witness values
+
+  pb.val(out) = 35;
+  pb.val(x) = 3;
+
+  g.generate_r1cs_witness();
+
+  if (pb.is_satisfied()) {
+    cout << "Constraint system is satisfied." << endl;
+  }
+  else {
+    cout << "Constraint system is not satisfied." << endl;
+  }
+
+  cout << "primary (public) input: " << pb.primary_input() << endl;
+  cout << "auxiliary (private) input: " << pb.auxiliary_input() << endl;
+  
+  const r1cs_constraint_system<FieldT> constraint_system = pb.get_constraint_system();
+  
+  cout << "Number of R1CS constraints: " << constraint_system.num_constraints() << endl;
+
+  r1cs_ppzksnark_keypair<default_r1cs_ppzksnark_pp> keypair = r1cs_ppzksnark_generator<default_r1cs_ppzksnark_pp>(constraint_system);
+
+  r1cs_ppzksnark_proof<default_r1cs_ppzksnark_pp> proof = r1cs_ppzksnark_prover<default_r1cs_ppzksnark_pp>(keypair.pk, pb.primary_input(), pb.auxiliary_input());
+
+  bool verified = r1cs_ppzksnark_verifier_strong_IC<default_r1cs_ppzksnark_pp>(keypair.vk, pb.primary_input(), proof);
+
+  cout << "Primary (public) input: " << pb.primary_input() << endl;
+  cout << "Auxiliary (private) input: " << pb.auxiliary_input() << endl;
+
+  cout << "Verification status: " << verified << endl;
+
+  return 0;
+}