From c497f0153e8e2cbdd3442ab16a019cefadbb5432 Mon Sep 17 00:00:00 2001
From: bazzilic <bazzilic@gmail.com>
Date: Wed, 30 Aug 2023 22:27:09 +0800
Subject: [PATCH] serialization and hash for NoteCommitment

---
 taiga_halo2/Cargo.toml         |  2 +-
 taiga_halo2/src/note.rs        | 51 +++++++++++++++++++++++++++++++++-
 taiga_halo2/src/transaction.rs | 31 +++++----------------
 3 files changed, 58 insertions(+), 26 deletions(-)

diff --git a/taiga_halo2/Cargo.toml b/taiga_halo2/Cargo.toml
index 4af454e2..24c22e99 100644
--- a/taiga_halo2/Cargo.toml
+++ b/taiga_halo2/Cargo.toml
@@ -44,6 +44,6 @@ name = "taiga_sudoku"
 name = "tx_examples"
 
 [features]
-default = []
+default = ["borsh", "serde"]
 serde = ["dep:serde", "pasta_curves/serde"]
 borsh = ["dep:borsh"]
diff --git a/taiga_halo2/src/note.rs b/taiga_halo2/src/note.rs
index 78bfca43..7f04e103 100644
--- a/taiga_halo2/src/note.rs
+++ b/taiga_halo2/src/note.rs
@@ -31,7 +31,8 @@ use serde;
 use borsh::{BorshDeserialize, BorshSerialize};
 
 /// A commitment to a note.
-#[derive(Copy, Debug, Clone)]
+#[derive(Copy, Debug, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct NoteCommitment(pallas::Point);
 
 impl NoteCommitment {
@@ -54,6 +55,32 @@ impl Default for NoteCommitment {
     }
 }
 
+#[cfg(feature = "borsh")]
+impl BorshSerialize for NoteCommitment {
+    fn serialize<W: std::io::Write>(&self, writer: &mut W) -> std::io::Result<()> {
+        writer.write_all(&self.0.to_bytes())?;
+        Ok(())
+    }
+}
+
+#[cfg(feature = "borsh")]
+impl BorshDeserialize for NoteCommitment {
+    fn deserialize_reader<R: std::io::Read>(reader: &mut R) -> std::io::Result<Self> {
+        let mut repr = [0u8; 32];
+        reader.read_exact(&mut repr)?;
+        let value = Option::from(pallas::Point::from_bytes(&repr)).ok_or_else(|| {
+            std::io::Error::new(std::io::ErrorKind::InvalidData, "Node value not in field")
+        })?;
+        Ok(Self(value))
+    }
+}
+
+impl Hash for NoteCommitment {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.0.to_bytes().as_ref().hash(state);
+    }
+}
+
 /// A note
 #[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
@@ -624,6 +651,8 @@ pub mod tests {
     fn note_borsh_serialization_test() {
         use borsh::{BorshDeserialize, BorshSerialize};
         use rand::rngs::OsRng;
+
+        use crate::note::NoteCommitment;
         let mut rng = OsRng;
 
         let input_note = random_input_note(&mut rng);
@@ -643,5 +672,25 @@ pub mod tests {
             let de_note: Note = BorshDeserialize::deserialize(&mut borsh.as_ref()).unwrap();
             assert_eq!(output_note, de_note);
         }
+
+        let icm = input_note.commitment();
+        {
+            // BorshSerialize
+            let borsh = icm.try_to_vec().unwrap();
+            // BorshDeserialize
+            let de_icm: NoteCommitment =
+                BorshDeserialize::deserialize(&mut borsh.as_ref()).unwrap();
+            assert_eq!(icm, de_icm);
+        }
+
+        let ocm = output_note.commitment();
+        {
+            // BorshSerialize
+            let borsh = ocm.try_to_vec().unwrap();
+            // BorshDeserialize
+            let de_ocm: NoteCommitment =
+                BorshDeserialize::deserialize(&mut borsh.as_ref()).unwrap();
+            assert_eq!(ocm, de_ocm);
+        }
     }
 }
diff --git a/taiga_halo2/src/transaction.rs b/taiga_halo2/src/transaction.rs
index 24d7a31b..0be1baee 100644
--- a/taiga_halo2/src/transaction.rs
+++ b/taiga_halo2/src/transaction.rs
@@ -351,26 +351,6 @@ pub mod testing {
 
     #[test]
     fn test_halo2_transaction() {
-        use super::Transaction;
-        use rand::rngs::OsRng;
-
-        let rng = OsRng;
-
-        let (shielded_ptx_bundle, r_vec) = create_shielded_ptx_bundle(2);
-        // TODO: add transparent_ptx_bundle test
-        let transparent_ptx_bundle = None;
-        let tx = Transaction::build(
-            rng,
-            Some(shielded_ptx_bundle),
-            transparent_ptx_bundle,
-            r_vec,
-        );
-        let (_, _) = tx.execute().unwrap();
-    }
-
-    #[cfg(feature = "borsh")]
-    #[test]
-    fn test_halo2_transaction_borsh_serialize() {
         use super::Transaction;
         use borsh::{BorshDeserialize, BorshSerialize};
         use rand::rngs::OsRng;
@@ -388,9 +368,12 @@ pub mod testing {
         );
         let (shielded_ret, _) = tx.execute().unwrap();
 
-        let borsh = tx.try_to_vec().unwrap();
-        let de_tx: Transaction = BorshDeserialize::deserialize(&mut borsh.as_ref()).unwrap();
-        let (de_shielded_ret, _) = de_tx.execute().unwrap();
-        assert_eq!(shielded_ret, de_shielded_ret);
+        #[cfg(feature = "borsh")]
+        {
+            let borsh = tx.try_to_vec().unwrap();
+            let de_tx: Transaction = BorshDeserialize::deserialize(&mut borsh.as_ref()).unwrap();
+            let (de_shielded_ret, _) = de_tx.execute().unwrap();
+            assert_eq!(shielded_ret, de_shielded_ret);
+        }
     }
 }