Implement serde serialization for Sapling nodes

Cargo.toml

@@ -8,7 +8,7 @@ members = [
 
 
 [workspace.package]
-version = "3.0.9"
+version = "3.0.10"
 
 [profile.release]
 lto = true

masp_primitives/Cargo.toml

@@ -73,6 +73,8 @@ blake2s_simd = "1"
 aes = "0.8"
 fpe = "0.6"
 
+serde = {version = "1.0.228", features = ["derive"], optional = true}
+serde-hex = {version = "0.1.0", optional = true}
 borsh = {version = "1.2.0", features = ["unstable__schema", "derive"]}
 arbitrary = {version = "1.3", features = ["derive"], optional = true }
 
@@ -89,6 +91,7 @@ assert_matches = "1.3.0"
 rand_xorshift = "0.3"
 
 [features]
+serde = ["dep:serde", "dep:serde-hex"]
 transparent-inputs = []
 test-dependencies = ["proptest"]
 default = ["transparent-inputs"]

masp_primitives/src/sapling.rs

@@ -17,6 +17,10 @@ use group::{Curve, Group, GroupEncoding, cofactor::CofactorGroup};
 use incrementalmerkletree::{self, Level};
 use lazy_static::lazy_static;
 use rand_core::{CryptoRng, RngCore};
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+#[cfg(feature = "serde")]
+use serde_hex::{SerHex, Strict};
 use std::{
     array::TryFromSliceError,
     cmp::Ordering,
@@ -85,9 +89,12 @@ pub fn merkle_hash(depth: usize, lhs: &[u8; 32], rhs: &[u8; 32]) -> [u8; 32] {
 }
 
 /// A node within the Sapling commitment tree.
-#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq, BorshSerialize, BorshDeserialize, Default)]
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[repr(transparent)]
 pub struct Node {
+    #[cfg_attr(feature = "serde", serde(with = "SerHex::<Strict>"))]
     repr: [u8; 32],
 }