Rename beacon_chain/ -> eth2/

eth2/utils/bls/src/aggregate_signature.rs

@@ -0,0 +1,65 @@
+use super::ssz::{decode_ssz_list, Decodable, DecodeError, Encodable, SszStream};
+use super::{AggregatePublicKey, Signature};
+use bls_aggregates::AggregateSignature as RawAggregateSignature;
+
+/// A BLS aggregate signature.
+///
+/// This struct is a wrapper upon a base type and provides helper functions (e.g., SSZ
+/// serialization).
+#[derive(Debug, PartialEq, Clone, Default, Eq)]
+pub struct AggregateSignature(RawAggregateSignature);
+
+impl AggregateSignature {
+    /// Instantiate a new AggregateSignature.
+    pub fn new() -> Self {
+        AggregateSignature(RawAggregateSignature::new())
+    }
+
+    /// Add (aggregate) a signature to the `AggregateSignature`.
+    pub fn add(&mut self, signature: &Signature) {
+        self.0.add(signature.as_raw())
+    }
+
+    /// Verify the `AggregateSignature` against an `AggregatePublicKey`.
+    ///
+    /// Only returns `true` if the set of keys in the `AggregatePublicKey` match the set of keys
+    /// that signed the `AggregateSignature`.
+    pub fn verify(&self, msg: &[u8], aggregate_public_key: &AggregatePublicKey) -> bool {
+        self.0.verify(msg, aggregate_public_key)
+    }
+}
+
+impl Encodable for AggregateSignature {
+    fn ssz_append(&self, s: &mut SszStream) {
+        s.append_vec(&self.0.as_bytes());
+    }
+}
+
+impl Decodable for AggregateSignature {
+    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
+        let (sig_bytes, i) = decode_ssz_list(bytes, i)?;
+        let raw_sig =
+            RawAggregateSignature::from_bytes(&sig_bytes).map_err(|_| DecodeError::TooShort)?;
+        Ok((AggregateSignature(raw_sig), i))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::super::ssz::ssz_encode;
+    use super::super::{Keypair, Signature};
+    use super::*;
+
+    #[test]
+    pub fn test_ssz_round_trip() {
+        let keypair = Keypair::random();
+
+        let mut original = AggregateSignature::new();
+        original.add(&Signature::new(&[42, 42], &keypair.sk));
+
+        let bytes = ssz_encode(&original);
+        let (decoded, _) = AggregateSignature::ssz_decode(&bytes, 0).unwrap();
+
+        assert_eq!(original, decoded);
+    }
+}