Added serde feature

.github/workflows/dusk_ci.yml

@@ -26,3 +26,9 @@ jobs:
     uses: dusk-network/.github/.github/workflows/run-tests.yml@main
     with:
       test_flags: --no-default-features 
+
+  test_serde:
+    name: Serde tests
+    uses: dusk-network/.github/.github/workflows/run-tests.yml@main
+    with:
+      test_flags: --features=serde

Cargo.toml

@@ -66,6 +66,18 @@ default-features = false
 version = "1"
 optional = true
 default-features = false
+
+[dependencies.serde]
+version = "1.0"
+optional = true
+
+[dependencies.serde_json]
+version = "1.0"
+optional = true
+
+[dependencies.hex]
+version = "0.4"
+optional = true
 # End Dusk dependendencies
 
 [dev-dependencies]
@@ -86,6 +98,7 @@ default = ["alloc", "bits"]
 alloc = ["ff/alloc", "group/alloc"]
 bits = ["ff/bits"]
 rkyv-impl = ["bytecheck", "dusk-bls12_381/rkyv-impl", "rkyv"]
+serde = ["dep:serde", "serde_json", "hex"]
 
 [[bench]]
 name = "fq_bench"

src/dusk.rs

@@ -7,6 +7,9 @@
 #[cfg(feature = "alloc")]
 extern crate alloc;
 
+#[cfg(feature = "serde")]
+mod serde_support;
+
 use core::ops::Mul;
 use ff::Field;
 use subtle::{Choice, ConditionallySelectable, ConstantTimeEq, CtOption};

src/dusk/serde_support.rs

@@ -0,0 +1,89 @@
+extern crate alloc;
+
+use alloc::string::String;
+
+use serde::{de::Error, Deserialize, Deserializer, Serialize, Serializer};
+
+use crate::{AffinePoint, ExtendedPoint};
+
+impl Serialize for AffinePoint {
+    fn serialize<S: Serializer>(
+        &self,
+        serializer: S,
+    ) -> Result<S::Ok, S::Error> {
+        let s = hex::encode(self.to_bytes());
+        serializer.serialize_str(&s)
+    }
+}
+
+impl<'de> Deserialize<'de> for AffinePoint {
+    fn deserialize<D: Deserializer<'de>>(
+        deserializer: D,
+    ) -> Result<Self, D::Error> {
+        let s = String::deserialize(deserializer)?;
+        let bytes: [u8; 32] = hex::decode(s)
+            .map_err(Error::custom)?
+            .try_into()
+            .map_err(|_| {
+                Error::custom(
+                    "Failed to deserialize AffinePoint: invalid byte length",
+                )
+            })?;
+        AffinePoint::from_bytes(bytes)
+            .into_option()
+            .ok_or(Error::custom(
+                "Failed to deserialize AffinePoint: invalid AffinePoint",
+            ))
+    }
+}
+
+impl Serialize for ExtendedPoint {
+    fn serialize<S: Serializer>(
+        &self,
+        serializer: S,
+    ) -> Result<S::Ok, S::Error> {
+        AffinePoint::from(self).serialize(serializer)
+    }
+}
+
+impl<'de> Deserialize<'de> for ExtendedPoint {
+    fn deserialize<D: Deserializer<'de>>(
+        deserializer: D,
+    ) -> Result<Self, D::Error> {
+        AffinePoint::deserialize(deserializer).map(Into::into)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use ff::Field;
+    use group::Group;
+
+    use crate::{AffinePoint, ExtendedPoint, Fr};
+
+    #[test]
+    fn affine_point() {
+        let point = AffinePoint::identity();
+        let ser = serde_json::to_string(&point).unwrap();
+        let deser = serde_json::from_str(&ser).unwrap();
+        assert_eq!(point, deser);
+    }
+
+    #[test]
+    fn extended_point() {
+        let mut rng = rand_core::OsRng;
+        let point = ExtendedPoint::random(&mut rng);
+        let ser = serde_json::to_string(&point).unwrap();
+        let deser = serde_json::from_str(&ser).unwrap();
+        assert_eq!(point, deser);
+    }
+
+    #[test]
+    fn fr() {
+        let mut rng = rand_core::OsRng;
+        let fr = Fr::random(&mut rng);
+        let ser = serde_json::to_string(&fr).unwrap();
+        let deser = serde_json::from_str(&ser).unwrap();
+        assert_eq!(fr, deser);
+    }
+}

src/fr/dusk.rs

@@ -275,6 +275,46 @@ impl Serializable<32> for Fr {
     }
 }
 
+#[cfg(feature = "serde")]
+mod serde_support {
+    extern crate alloc;
+
+    use alloc::string::String;
+
+    use serde::{de::Error, Deserialize, Deserializer, Serialize, Serializer};
+
+    use super::Fr;
+
+    impl Serialize for Fr {
+        fn serialize<S: Serializer>(
+            &self,
+            serializer: S,
+        ) -> Result<S::Ok, S::Error> {
+            let s = hex::encode(self.to_bytes());
+            serializer.serialize_str(&s)
+        }
+    }
+
+    impl<'de> Deserialize<'de> for Fr {
+        fn deserialize<D: Deserializer<'de>>(
+            deserializer: D,
+        ) -> Result<Self, D::Error> {
+            let s = String::deserialize(deserializer)?;
+            let bytes: [u8; 32] = hex::decode(s)
+                .map_err(Error::custom)?
+                .try_into()
+                .map_err(|_| {
+                    Error::custom(
+                        "Failed to deserialize Fr: invalid byte length",
+                    )
+                })?;
+            Fr::from_bytes(&bytes)
+                .into_option()
+                .ok_or(Error::custom("Failed to deserialize Fr: invalid Fr"))
+        }
+    }
+}
+
 #[test]
 fn w_naf_3() {
     let scalar = Fr::from(1122334455u64);