From ca3ec9f5d4f1582fc18a3be7da973e63b60fde63 Mon Sep 17 00:00:00 2001
From: Sean Bowe <ewillbefull@gmail.com>
Date: Sat, 5 Dec 2015 15:03:33 -0700
Subject: [PATCH] Foundations for encrypted sodoku solution

---
 src/gadget.hpp | 21 ++++++++++++++++++++-
 src/gadget.tcc | 36 ++++++++++++++++++++++++++++++++++++
 src/snark.hpp  | 11 ++++++++++-
 src/snark.tcc  | 11 -----------
 4 files changed, 66 insertions(+), 13 deletions(-)

diff --git a/src/gadget.hpp b/src/gadget.hpp
index be07323..e372de4 100644
--- a/src/gadget.hpp
+++ b/src/gadget.hpp
@@ -3,10 +3,26 @@
 
 using namespace libsnark;
 
+template<typename FieldT>
+class sodoku_encryption_key : public gadget<FieldT> {
+public:
+    pb_variable_array<FieldT> seed_key; // 256 bit key
+    unsigned int dimension;
+
+    std::vector<std::shared_ptr<digest_variable<FieldT>>> key; // dimension*dimension*8 bit key
+
+    sodoku_encryption_key(protoboard<FieldT> &pb,
+                       unsigned int dimension,
+                       pb_variable_array<FieldT> &seed_key
+                       );
+    void generate_r1cs_constraints();
+    void generate_r1cs_witness();
+};
+
 template<typename FieldT>
 class sodoku_cell_gadget : public gadget<FieldT> {
 public:
-    pb_linear_combination<FieldT> &number;
+    pb_linear_combination<FieldT> number;
     unsigned int dimension;
 
     /*
@@ -67,6 +83,9 @@ public:
     std::vector<std::shared_ptr<sodoku_closure_gadget<FieldT>>> closure_cols;
     std::vector<std::shared_ptr<sodoku_closure_gadget<FieldT>>> closure_groups;
 
+    std::shared_ptr<digest_variable<FieldT>> seed_key;
+    std::shared_ptr<sodoku_encryption_key<FieldT>> key;
+
     pb_variable_array<FieldT> puzzle_enforce;
 
 
diff --git a/src/gadget.tcc b/src/gadget.tcc
index 35f034f..d1d09c9 100644
--- a/src/gadget.tcc
+++ b/src/gadget.tcc
@@ -1,3 +1,31 @@
+template<typename FieldT>
+sodoku_encryption_key<FieldT>::sodoku_encryption_key(protoboard<FieldT> &pb,
+                                               unsigned int dimension,
+                                               pb_variable_array<FieldT> &seed_key
+                                               ) : gadget<FieldT>(pb, FMT(annotation_prefix, " sodoku_closure_gadget")),
+                                                   seed_key(seed_key), dimension(dimension)
+{
+    unsigned int num_key_digests = div_ceil(dimension * dimension * 8, 256);
+
+    key.resize(num_key_digests);
+
+    for (unsigned int i = 0; i < num_key_digests; i++) {
+        key[i].reset(new digest_variable<FieldT>(pb, 256, "key[i]"));
+    }
+}
+
+template<typename FieldT>
+void sodoku_encryption_key<FieldT>::generate_r1cs_constraints()
+{
+    
+}
+
+template<typename FieldT>
+void sodoku_encryption_key<FieldT>::generate_r1cs_witness()
+{
+    
+}
+
 template<typename FieldT>
 sodoku_closure_gadget<FieldT>::sodoku_closure_gadget(protoboard<FieldT> &pb,
                                                unsigned int dimension,
@@ -127,6 +155,9 @@ sodoku_gadget<FieldT>::sodoku_gadget(protoboard<FieldT> &pb, unsigned int n) :
         closure_groups[gi].reset(new sodoku_closure_gadget<FieldT>(this->pb, dimension, group_flags));
     }
 
+    seed_key.reset(new digest_variable<FieldT>(pb, 256, "seed_key"));
+    key.reset(new sodoku_encryption_key<FieldT>(pb, dimension, seed_key->bits));
+
     assert(input_as_bits.size() == input_size_in_bits);
     unpack_inputs.reset(new multipacking_gadget<FieldT>(this->pb, input_as_bits, input_as_field_elements, FieldT::capacity(), FMT(this->annotation_prefix, " unpack_inputs")));
 }
@@ -161,6 +192,9 @@ void sodoku_gadget<FieldT>::generate_r1cs_constraints()
         closure_groups[i]->generate_r1cs_constraints();
     }
 
+    seed_key->generate_r1cs_constraints();
+    key->generate_r1cs_constraints();
+
     unpack_inputs->generate_r1cs_constraints(true);
 }
 
@@ -195,6 +229,8 @@ void sodoku_gadget<FieldT>::generate_r1cs_witness(std::vector<bit_vector> &input
         cells[i]->generate_r1cs_witness();
     }
 
+    key->generate_r1cs_witness();
+
     unpack_inputs->generate_r1cs_witness_from_bits();
 }
 
diff --git a/src/snark.hpp b/src/snark.hpp
index 4e480e0..569c6ab 100644
--- a/src/snark.hpp
+++ b/src/snark.hpp
@@ -6,7 +6,16 @@
 
 using namespace libsnark;
 
-std::vector<std::vector<bool>> convertPuzzleToBool(std::vector<uint8_t>);
+std::vector<bool> convertIntToVector(uint8_t val) {
+  std::vector<bool> ret;
+
+  for(unsigned int i = 0; i < sizeof(val) * 8; ++i, val >>= 1) {
+    ret.push_back(val & 0x01);
+  }
+
+  reverse(ret.begin(), ret.end());
+  return ret;
+}
 
 template<typename ppzksnark_ppT>
 r1cs_ppzksnark_keypair<ppzksnark_ppT> generate_keypair();
diff --git a/src/snark.tcc b/src/snark.tcc
index bfbdded..a9b17f9 100644
--- a/src/snark.tcc
+++ b/src/snark.tcc
@@ -2,17 +2,6 @@
 
 using namespace std;
 
-std::vector<bool> convertIntToVector(uint8_t val) {
-  std::vector<bool> ret;
-
-  for(unsigned int i = 0; i < sizeof(val) * 8; ++i, val >>= 1) {
-    ret.push_back(val & 0x01);
-  }
-
-  reverse(ret.begin(), ret.end());
-  return ret;
-}
-
 std::vector<std::vector<bool>> convertPuzzleToBool(std::vector<uint8_t> puzzle) {
     std::vector<vector<bool>> new_puzzle;