Add newtype for bls::PublicKey

beacon_chain/utils/bls/src/lib.rs

@@ -3,20 +3,22 @@ extern crate hashing;
 extern crate ssz;
 
 mod aggregate_signature;
+mod public_key;
 mod signature;
 
 pub use crate::aggregate_signature::AggregateSignature;
 pub use crate::signature::Signature;
+pub use crate::public_key::PublicKey;
 
 pub use self::bls_aggregates::AggregatePublicKey;
 pub use self::bls_aggregates::Keypair;
-pub use self::bls_aggregates::PublicKey;
 pub use self::bls_aggregates::SecretKey;
 
 pub const BLS_AGG_SIG_BYTE_SIZE: usize = 97;
 
 use hashing::canonical_hash;
 use std::default::Default;
+use ssz::ssz_encode;
 
 fn extend_if_needed(hash: &mut Vec<u8>) {
     // NOTE: bls_aggregates crate demands 48 bytes, this may be removed as we get closer to production
@@ -26,7 +28,7 @@ fn extend_if_needed(hash: &mut Vec<u8>) {
 /// For some signature and public key, ensure that the signature message was the public key and it
 /// was signed by the secret key that corresponds to that public key.
 pub fn verify_proof_of_possession(sig: &Signature, pubkey: &PublicKey) -> bool {
-    let mut hash = canonical_hash(&pubkey.as_bytes());
+    let mut hash = canonical_hash(&ssz_encode(pubkey));
     extend_if_needed(&mut hash);
     sig.verify_hashed(&hash, &pubkey)
 }

beacon_chain/utils/bls/src/public_key.rs

@@ -0,0 +1,52 @@
+use super::SecretKey;
+use bls_aggregates::PublicKey as RawPublicKey;
+use ssz::{decode_ssz_list, Decodable, DecodeError, Encodable, SszStream};
+
+/// A single BLS signature.
+///
+/// This struct is a wrapper upon a base type and provides helper functions (e.g., SSZ
+/// serialization).
+#[derive(Debug, PartialEq, Clone)]
+pub struct PublicKey(RawPublicKey);
+
+impl PublicKey {
+    pub fn from_secret_key(secret_key: &SecretKey) -> Self {
+        PublicKey(RawPublicKey::from_secret_key(secret_key))
+    }
+
+    /// Returns the underlying signature.
+    pub fn as_raw(&self) -> &RawPublicKey {
+        &self.0
+    }
+}
+
+impl Encodable for PublicKey {
+    fn ssz_append(&self, s: &mut SszStream) {
+        s.append_vec(&self.0.as_bytes());
+    }
+}
+
+impl Decodable for PublicKey {
+    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
+        let (sig_bytes, i) = decode_ssz_list(bytes, i)?;
+        let raw_sig = RawPublicKey::from_bytes(&sig_bytes).map_err(|_| DecodeError::TooShort)?;
+        Ok((PublicKey(raw_sig), i))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::super::ssz::ssz_encode;
+    use super::*;
+
+    #[test]
+    pub fn test_ssz_round_trip() {
+        let sk = SecretKey::random();
+        let original = PublicKey::from_secret_key(&sk);
+
+        let bytes = ssz_encode(&original);
+        let (decoded, _) = PublicKey::ssz_decode(&bytes, 0).unwrap();
+
+        assert_eq!(original, decoded);
+    }
+}

beacon_chain/utils/bls/src/signature.rs

@@ -1,5 +1,6 @@
 use super::ssz::{decode_ssz_list, Decodable, DecodeError, Encodable, SszStream};
-use bls_aggregates::{PublicKey, SecretKey, Signature as RawSignature};
+use super::PublicKey;
+use bls_aggregates::{SecretKey, Signature as RawSignature};
 
 /// A single BLS signature.
 ///
@@ -22,12 +23,12 @@ impl Signature {
 
     /// Verify the Signature against a PublicKey.
     pub fn verify(&self, msg: &[u8], pk: &PublicKey) -> bool {
-        self.0.verify(msg, pk)
+        self.0.verify(msg, pk.as_raw())
     }
 
     /// Verify the Signature against a PublicKey, where the message has already been hashed.
     pub fn verify_hashed(&self, msg_hash: &[u8], pk: &PublicKey) -> bool {
-        self.0.verify_hashed(msg_hash, pk)
+        self.0.verify_hashed(msg_hash, pk.as_raw())
     }
 
     /// Returns the underlying signature.