lighthouse/eth2/utils/bls/src/aggregate_signature.rs
2019-01-25 17:23:14 +11:00

72 lines
2.2 KiB
Rust

use super::{AggregatePublicKey, Signature};
use bls_aggregates::AggregateSignature as RawAggregateSignature;
use ssz::{decode_ssz_list, hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
/// 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))
}
}
impl TreeHash for AggregateSignature {
fn hash_tree_root(&self) -> Vec<u8> {
hash(&self.0.as_bytes())
}
}
#[cfg(test)]
mod tests {
use super::super::{Keypair, Signature};
use super::*;
use ssz::ssz_encode;
#[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);
}
}