add feature-gated serde 1.0 support for Signature, SecretKey, PublicKey

.travis.yml

@@ -10,6 +10,7 @@ script:
   - cargo build --verbose --features=fuzztarget
   - cargo build --verbose --features=rand
   - cargo test --verbose --features=rand
+  - cargo test --verbose --features="rand serde"
   - cargo build --verbose
   - cargo test --verbose
   - cargo build --release

Cargo.toml

@@ -27,6 +27,7 @@ fuzztarget = []
 
 [dev-dependencies]
 rand = "0.3"
+serde_test = "1.0"
 
 [dependencies]
 libc = "0.2"
@@ -34,3 +35,7 @@ libc = "0.2"
 [dependencies.rand]
 version = "0.3"
 optional = true
+
+[dependencies.serde]
+version = "1.0"
+optional = true

src/key.rs

@@ -121,6 +121,31 @@ impl SecretKey {
     }
 }
 
+#[cfg(feature = "serde")]
+impl ::serde::Serialize for SecretKey {
+    fn serialize<S: ::serde::Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
+        s.serialize_bytes(&self.0)
+    }
+}
+
+#[cfg(feature = "serde")]
+impl<'de> ::serde::Deserialize<'de> for SecretKey {
+    fn deserialize<D: ::serde::Deserializer<'de>>(d: D) -> Result<SecretKey, D::Error> {
+        use ::serde::de::Error;
+
+        // serde can actually deserialize a 32-byte array directly rather than deserializing
+        // a byte slice and copying, but it has special code for byte-slices and no special
+        // code for byte-arrays, meaning this is actually simpler and more efficient
+        let mut arr = [0; 32];
+        let sl: &[u8] = ::serde::Deserialize::deserialize(d)?;
+        if sl.len() != constants::SECRET_KEY_SIZE {
+            return Err(D::Error::invalid_length(sl.len(), &"32"));
+        }
+        arr.copy_from_slice(sl);
+        Ok(SecretKey(arr))
+    }
+}
+
 impl PublicKey {
     /// Obtains a raw pointer suitable for use with FFI functions
     #[inline]
@@ -254,6 +279,24 @@ impl From<ffi::PublicKey> for PublicKey {
     }
 }
 
+#[cfg(feature = "serde")]
+impl ::serde::Serialize for PublicKey {
+    fn serialize<S: ::serde::Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
+        s.serialize_bytes(&self.serialize())
+    }
+}
+
+#[cfg(feature = "serde")]
+impl<'de> ::serde::Deserialize<'de> for PublicKey {
+    fn deserialize<D: ::serde::Deserializer<'de>>(d: D) -> Result<PublicKey, D::Error> {
+        use ::serde::de::Error;
+
+        let secp = Secp256k1::without_caps();
+        let sl: &[u8] = ::serde::Deserialize::deserialize(d)?;
+        PublicKey::from_slice(&secp, sl).map_err(D::Error::custom)
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::super::{Secp256k1};
@@ -529,6 +572,33 @@ mod test {
         assert!(pk3 <= pk1);
         assert!(pk1 >= pk3);
     }
+
+    #[cfg(feature = "serde")]
+    #[test]
+    fn test_signature_serde() {
+        use serde_test::{Token, assert_tokens};
+        static SK_BYTES: [u8; 32] = [
+            1, 1, 1, 1, 1, 1, 1, 1,
+            0, 1, 2, 3, 4, 5, 6, 7,
+            0xff, 0xff, 0, 0, 0xff, 0xff, 0, 0,
+            99, 99, 99, 99, 99, 99, 99, 99
+        ];
+        static PK_BYTES: [u8; 33] = [
+            0x02,
+            0x18, 0x84, 0x57, 0x81, 0xf6, 0x31, 0xc4, 0x8f,
+            0x1c, 0x97, 0x09, 0xe2, 0x30, 0x92, 0x06, 0x7d,
+            0x06, 0x83, 0x7f, 0x30, 0xaa, 0x0c, 0xd0, 0x54,
+            0x4a, 0xc8, 0x87, 0xfe, 0x91, 0xdd, 0xd1, 0x66,
+        ];
+
+        let s = Secp256k1::new();
+
+        let sk = SecretKey::from_slice(&s, &SK_BYTES).unwrap();
+        let pk = PublicKey::from_secret_key(&s, &sk);
+
+        assert_tokens(&sk, &[Token::BorrowedBytes(&SK_BYTES[..])]);
+        assert_tokens(&pk, &[Token::BorrowedBytes(&PK_BYTES[..])]);
+    }
 }
 
 

src/lib.rs

@@ -39,6 +39,8 @@
 #![cfg_attr(all(test, feature = "unstable"), feature(test))]
 #[cfg(all(test, feature = "unstable"))] extern crate test;
 #[cfg(any(test, feature = "rand"))] extern crate rand;
+#[cfg(feature = "serde")] extern crate serde;
+#[cfg(all(test, feature = "serde"))] extern crate serde_test;
 
 extern crate libc;
 
@@ -305,6 +307,25 @@ impl ops::Index<ops::RangeFull> for Signature {
     }
 }
 
+#[cfg(feature = "serde")]
+impl ::serde::Serialize for Signature {
+    fn serialize<S: ::serde::Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
+        let secp = Secp256k1::without_caps();
+        s.serialize_bytes(&self.serialize_der(&secp))
+    }
+}
+
+#[cfg(feature = "serde")]
+impl<'de> ::serde::Deserialize<'de> for Signature {
+    fn deserialize<D: ::serde::Deserializer<'de>>(d: D) -> Result<Signature, D::Error> {
+        use ::serde::de::Error;
+
+        let secp = Secp256k1::without_caps();
+        let sl: &[u8] = ::serde::Deserialize::deserialize(d)?;
+        Signature::from_der(&secp, sl).map_err(D::Error::custom)
+    }
+}
+
 /// A (hashed) message input to an ECDSA signature
 pub struct Message([u8; constants::MESSAGE_SIZE]);
 impl_array_newtype!(Message, u8, constants::MESSAGE_SIZE);
@@ -903,6 +924,27 @@ mod tests {
         sig.normalize_s(&secp);
         assert_eq!(secp.verify(&msg, &sig, &pk), Ok(()));
     }
+
+    #[cfg(feature = "serde")]
+    #[test]
+    fn test_signature_serde() {
+        use serde_test::{Token, assert_tokens};
+
+        let s = Secp256k1::new();
+
+        let msg = Message::from_slice(&[1; 32]).unwrap();
+        let sk = SecretKey::from_slice(&s, &[2; 32]).unwrap();
+        let sig = s.sign(&msg, &sk);
+        static SIG_BYTES: [u8; 71] = [
+            48, 69, 2, 33, 0, 157, 11, 173, 87, 103, 25, 211, 42, 231, 107, 237,
+            179, 76, 119, 72, 102, 103, 60, 189, 227, 244, 225, 41, 81, 85, 92, 148,
+            8, 230, 206, 119, 75, 2, 32, 40, 118, 231, 16, 47, 32, 79, 107, 254,
+            226, 108, 150, 124, 57, 38, 206, 112, 44, 249, 125, 75, 1, 0, 98, 225,
+            147, 247, 99, 25, 15, 103, 118
+        ];
+
+        assert_tokens(&sig, &[Token::BorrowedBytes(&SIG_BYTES[..])]);
+    }
 }
 
 #[cfg(all(test, feature = "unstable"))]