From 4ae6616a2b5f4b3886d92cb574b10c3109fedd89 Mon Sep 17 00:00:00 2001
From: sowle <crypto.sowle@gmail.com>
Date: Tue, 21 Feb 2023 01:37:42 +0100
Subject: [PATCH] crypto: linear composition proof stub

---
 src/common/crypto_serialization.h | 17 ++++++++++++++++-
 src/crypto/zarcanum.h             | 24 ++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/src/common/crypto_serialization.h b/src/common/crypto_serialization.h
index 588deb69..2aef3cae 100644
--- a/src/common/crypto_serialization.h
+++ b/src/common/crypto_serialization.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2014-2022 Zano Project
+// Copyright (c) 2014-2023 Zano Project
 // Copyright (c) 2014-2018 The Louisdor Project
 // Copyright (c) 2012-2013 The Cryptonote developers
 // Distributed under the MIT/X11 software license, see the accompanying
@@ -152,6 +152,21 @@ namespace crypto
     END_BOOST_SERIALIZATION()
   };
 
+  struct linear_composition_proof_s : public linear_composition_proof
+  {
+    BEGIN_SERIALIZE_OBJECT()
+      FIELD(c)
+      FIELD(y0)
+      FIELD(y1)
+    END_SERIALIZE()
+
+    BEGIN_BOOST_SERIALIZATION()
+      BOOST_SERIALIZE(c)
+      BOOST_SERIALIZE(y0)
+      BOOST_SERIALIZE(y1)
+    END_BOOST_SERIALIZATION()
+  };
+
 
 } // namespace crypto
 
diff --git a/src/crypto/zarcanum.h b/src/crypto/zarcanum.h
index bfb20a53..ac517395 100644
--- a/src/crypto/zarcanum.h
+++ b/src/crypto/zarcanum.h
@@ -56,6 +56,30 @@ namespace crypto
     const zarcanum_proof& sig, uint8_t* p_err = nullptr);
 
 
+  // TODO @#@#: make sure it is used, implement, then move it to an appropriate place
+  struct linear_composition_proof
+  {
+    scalar_t  c;
+    scalar_t  y0;
+    scalar_t  y1;
+  };
+
+  enum generator_tag { generator_tag_void = 0, generator_tag_G = 1, generator_tag_H = 2, generator_tag_H2 = 3, generator_tag_X = 4, generator_tag_U = 5 };
+
+  template<generator_tag gen0 = generator_tag_H, generator_tag gen1 = generator_tag_G>
+  bool generate_linear_composition_proof(const hash& m, const public_key& A, const scalar_t& secret_a, const scalar_t& secret_b, linear_composition_proof& result, uint8_t* p_err = nullptr)
+  {
+    // consider embedding generators' tags into random entropy to distinguish proofs made with different generators during verification
+    return false;
+  }
+
+  template<generator_tag gen0 = generator_tag_H, generator_tag gen1 = generator_tag_G>
+  bool verify_linear_composition_proof(const hash& m, const public_key& A, const linear_composition_proof& sig, uint8_t* p_err = nullptr)
+  {
+    return false;
+  }
+
+
 
   // TODO: improve this proof using random weightning factor
   struct vector_UG_aggregation_proof