g2 deserialization also

crypto/src/json.rs

@@ -1,5 +1,5 @@
 use hex::FromHex;
-use bn::{self, Group, Fq, AffineG1};
+use bn::{self, Group, Fq, AffineG1, Fq2, AffineG2};
 
 use std::fmt;
 
@@ -10,10 +10,20 @@ pub struct G1(bn::G1);
 
 struct G1Visitor;
 
+fn clean_0x(s: &str) -> &str {
+	if s.starts_with("0x") {
+		&s[2..]
+	} else {
+		s
+	}
+}
+
 fn pop_fq<'de, A: de::SeqAccess<'de>>(value: &mut A) -> Result<Fq, A::Error> {
     let x: Vec<u8> = value
         .next_element::<String>()?
-        .ok_or(de::Error::custom("Should be 2 elements"))?
+        .as_ref()
+        .map(|s| clean_0x(s))
+        .ok_or(de::Error::custom("Expected next 256-bit number"))?
         .from_hex()
         .map_err(|e| de::Error::custom(format!("Invalid hex: {}", e)))?;
 
@@ -24,7 +34,7 @@ impl<'de> Visitor<'de> for G1Visitor {
     type Value = G1;
 
     fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        formatter.write_str("a sequence of 2 strings")
+        formatter.write_str("a sequence of 2 hex strings")
     }
 
     fn visit_seq<A>(self, mut value: A) -> Result<Self::Value, A::Error>
@@ -33,7 +43,7 @@ impl<'de> Visitor<'de> for G1Visitor {
     {
         let x = pop_fq(&mut value)?;
         let y = pop_fq(&mut value)?;
-        let affine_g1 = AffineG1::new(x, y).map_err(|e| de::Error::custom("Invalid curve point"))?;
+        let affine_g1 = AffineG1::new(x, y).map_err(|e| de::Error::custom("Invalid g1 curve point"))?;
 
         Ok(G1(affine_g1.into()))
     }
@@ -51,6 +61,43 @@ impl<'de> Deserialize<'de> for G1 {
 #[derive(Clone)]
 pub struct G2(bn::G2);
 
+struct G2Visitor;
+
+impl<'de> Visitor<'de> for G2Visitor {
+    type Value = G2;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str("a sequence of 4 hex strings")
+    }
+
+    fn visit_seq<A>(self, mut value: A) -> Result<Self::Value, A::Error>
+    where
+        A: de::SeqAccess<'de>,
+    {
+        let x_a = pop_fq(&mut value)?;
+        let x_b = pop_fq(&mut value)?;
+
+        let y_a = pop_fq(&mut value)?;
+        let y_b = pop_fq(&mut value)?;
+
+        let x = Fq2::new(x_b, x_a);
+        let y = Fq2::new(y_b, y_a);
+
+        let affine_g2 = AffineG2::new(x, y).map_err(|e| de::Error::custom("Invalid g2 curve point"))?;
+
+        Ok(G2(affine_g2.into()))
+    }
+}
+
+impl<'de> Deserialize<'de> for G2 {
+    fn deserialize<D>(deserializer: D) -> Result<G2, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        deserializer.deserialize_seq(G2Visitor)
+    }
+}
+
 #[derive(Clone)]
 pub struct VerifyingKey {
 	pub a: G2,
@@ -73,10 +120,19 @@ mod tests {
     #[test]
     fn g1() {
         let g1: G1 = serde_json::from_str(r#"[
-            "0aee46a7ea6e80a3675026dfa84019deee2a2dedb1bbe11d7fe124cb3efb4b5a",
-            "044747b6e9176e13ede3a4dfd0d33ccca6321b9acd23bf3683a60adc0366ebaf"
+            "0x0aee46a7ea6e80a3675026dfa84019deee2a2dedb1bbe11d7fe124cb3efb4b5a",
+            "0x044747b6e9176e13ede3a4dfd0d33ccca6321b9acd23bf3683a60adc0366ebaf"
         ]"#).unwrap();
 
     }
 
+    #[test]
+    fn g2() {
+        let g2: G2 = serde_json::from_str(r#"[
+            "0x1f39e4e4afc4bc74790a4a028aff2c3d2538731fb755edefd8cb48d6ea589b5e",
+            "0x283f150794b6736f670d6a1033f9b46c6f5204f50813eb85c8dc4b59db1c5d39",
+            "0x140d97ee4d2b36d99bc49974d18ecca3e7ad51011956051b464d9e27d46cc25e",
+            "0x0764bb98575bd466d32db7b15f582b2d5c452b36aa394b789366e5e3ca5aabd4"
+        ]"#).unwrap();
+    }
 }