FCMP++: tower cycle Curve class + hash_grow implementation + tests

- The Curve class is an abstract interface for curves that form
a cycle with another curve. This commit implements the Helios and
Selene objects inherited from the Curve parent class.
- This commit also tests the hash_grow flow under circumstances
that occur when the curve trees merkle tree grows, and implements
all the necessary functions on the Helios and Selene classes.

Author: j-berman

src/fcmp_pp/curve_trees.cpp

@@ -114,6 +114,20 @@ OutputTuple output_to_tuple(const OutputPair &output_pair)
     return output_tuple_from_bytes(O, I, C);
 }
 //----------------------------------------------------------------------------------------------------------------------
+std::shared_ptr<CurveTreesV1> curve_trees_v1(const std::size_t selene_chunk_width, const std::size_t helios_chunk_width)
+{
+    std::unique_ptr<Selene> selene(new Selene());
+    std::unique_ptr<Helios> helios(new Helios());
+    return std::shared_ptr<CurveTreesV1>(
+            new CurveTreesV1(
+                std::move(selene),
+                std::move(helios),
+                selene_chunk_width,
+                helios_chunk_width
+            )
+        );
+};
+//----------------------------------------------------------------------------------------------------------------------
 //----------------------------------------------------------------------------------------------------------------------
 // Static functions
 //----------------------------------------------------------------------------------------------------------------------

src/fcmp_pp/curve_trees.h

@@ -116,6 +116,19 @@ class CurveTrees
     const std::size_t m_c2_width;
 };
 //----------------------------------------------------------------------------------------------------------------------
+using Selene       = tower_cycle::Selene;
+using Helios       = tower_cycle::Helios;
+using CurveTreesV1 = CurveTrees<Selene, Helios>;
+
+// https://github.com/kayabaNerve/fcmp-plus-plus/blob
+//  /b2742e86f3d18155fd34dd1ed69cb8f79b900fce/crypto/fcmps/src/tests.rs#L81-L82
+const std::size_t SELENE_CHUNK_WIDTH = 38;
+const std::size_t HELIOS_CHUNK_WIDTH = 18;
+
+std::shared_ptr<CurveTreesV1> curve_trees_v1(
+    const std::size_t selene_chunk_width = SELENE_CHUNK_WIDTH,
+    const std::size_t helios_chunk_width = HELIOS_CHUNK_WIDTH);
+//----------------------------------------------------------------------------------------------------------------------
 //----------------------------------------------------------------------------------------------------------------------
 } //namespace curve_trees
 } //namespace fcmp_pp

src/fcmp_pp/fcmp_pp_rust/Cargo.lock

@@ -12,6 +12,11 @@ ciphersuite = { version = "0.4.2", features = ["ed25519"] }
 dalek-ff-group = "0.4.4"
 helioselene = { git = "https://github.com/monero-oxide/monero-oxide", rev = "50dd3dbc0cc9048247eb734d27eb1d516aecacd2" }
 
+full-chain-membership-proofs = { git = "https://github.com/monero-oxide/monero-oxide", rev = "50dd3dbc0cc9048247eb734d27eb1d516aecacd2" }
+
+monero-generators = { git = "https://github.com/monero-oxide/monero-oxide", rev = "50dd3dbc0cc9048247eb734d27eb1d516aecacd2" }
+monero-fcmp-plus-plus = { git = "https://github.com/monero-oxide/monero-oxide", rev = "50dd3dbc0cc9048247eb734d27eb1d516aecacd2" }
+
 [patch.crates-io]
 crypto-bigint = { git = "https://github.com/kayabaNerve/crypto-bigint", branch = "c-repr" }
 

src/fcmp_pp/fcmp_pp_rust/Cargo.toml

@@ -38,6 +38,23 @@ struct SeleneScalar {
   uintptr_t _0[32 / sizeof(uintptr_t)];
 };
 
+/// The field novel to Helios/Selene.
+struct HeliosScalar {
+  uintptr_t _0[32 / sizeof(uintptr_t)];
+};
+
+struct HeliosPoint {
+  struct SeleneScalar x;
+  struct SeleneScalar y;
+  struct SeleneScalar z;
+};
+
+struct SelenePoint {
+  struct HeliosScalar x;
+  struct HeliosScalar y;
+  struct HeliosScalar z;
+};
+
 // ----- End deps C bindings -----
 
 struct OutputTuple
@@ -47,12 +64,64 @@ struct OutputTuple
   uint8_t C[32];
 };
 
+struct HeliosScalarSlice
+{
+  const struct HeliosScalar *buf;
+  uintptr_t len;
+};
+
+struct SeleneScalarSlice
+{
+  const struct SeleneScalar *buf;
+  uintptr_t len;
+};
+
+struct HeliosScalarChunks
+{
+  const struct HeliosScalarSlice *buf;
+  uintptr_t len;
+};
+
+struct SeleneScalarChunks
+{
+  const struct SeleneScalarSlice *buf;
+  uintptr_t len;
+};
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 int selene_scalar_from_bytes(const uint8_t *selene_scalar_bytes, struct SeleneScalar *selene_scalar_out);
 
+struct HeliosPoint helios_hash_init_point(void);
+
+struct SelenePoint selene_hash_init_point(void);
+
+struct HeliosScalar helios_zero_scalar(void);
+
+struct SeleneScalar selene_zero_scalar(void);
+
+void helios_scalar_to_bytes(const struct HeliosScalar *helios_scalar, uint8_t bytes_out[32]);
+
+void selene_scalar_to_bytes(const struct SeleneScalar *selene_scalar, uint8_t bytes_out[32]);
+
+void helios_point_to_bytes(const struct HeliosPoint *helios_point, uint8_t bytes_out[32]);
+
+void selene_point_to_bytes(const struct SelenePoint *selene_point, uint8_t bytes_out[32]);
+
+int hash_grow_helios(struct HeliosPoint existing_hash,
+                                             uintptr_t offset,
+                                             struct HeliosScalar existing_child_at_offset,
+                                             struct HeliosScalarSlice new_children,
+                                             struct HeliosPoint *hash_out);
+
+int hash_grow_selene(struct SelenePoint existing_hash,
+                                             uintptr_t offset,
+                                             struct SeleneScalar existing_child_at_offset,
+                                             struct SeleneScalarSlice new_children,
+                                             struct SelenePoint *hash_out);
+
 #ifdef __cplusplus
 } //extern "C"
 #endif