142 lines
4.3 KiB
Rust
142 lines
4.3 KiB
Rust
use super::serde_vistors::HexVisitor;
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use super::{PublicKey, SecretKey};
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use bls_aggregates::Signature as RawSignature;
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use hex::encode as hex_encode;
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use serde::de::{Deserialize, Deserializer};
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use serde::ser::{Serialize, Serializer};
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use ssz::{
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decode_ssz_list, hash, ssz_encode, Decodable, DecodeError, Encodable, SszStream, TreeHash,
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};
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/// A single BLS signature.
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///
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/// This struct is a wrapper upon a base type and provides helper functions (e.g., SSZ
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/// serialization).
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#[derive(Debug, PartialEq, Clone, Eq)]
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pub struct Signature(RawSignature);
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impl Signature {
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/// Instantiate a new Signature from a message and a SecretKey.
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pub fn new(msg: &[u8], domain: u64, sk: &SecretKey) -> Self {
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Signature(RawSignature::new(msg, domain, sk.as_raw()))
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}
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/// Instantiate a new Signature from a message and a SecretKey, where the message has already
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/// been hashed.
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pub fn new_hashed(x_real_hashed: &[u8], x_imaginary_hashed: &[u8], sk: &SecretKey) -> Self {
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Signature(RawSignature::new_hashed(
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x_real_hashed,
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x_imaginary_hashed,
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sk.as_raw(),
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))
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}
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/// Verify the Signature against a PublicKey.
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pub fn verify(&self, msg: &[u8], domain: u64, pk: &PublicKey) -> bool {
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self.0.verify(msg, domain, pk.as_raw())
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}
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/// Verify the Signature against a PublicKey, where the message has already been hashed.
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pub fn verify_hashed(
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&self,
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x_real_hashed: &[u8],
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x_imaginary_hashed: &[u8],
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pk: &PublicKey,
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) -> bool {
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self.0
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.verify_hashed(x_real_hashed, x_imaginary_hashed, pk.as_raw())
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}
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/// Returns the underlying signature.
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pub fn as_raw(&self) -> &RawSignature {
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&self.0
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}
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/// Returns a new empty signature.
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pub fn empty_signature() -> Self {
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// Empty Signature is currently being represented as BLS::Signature.point_at_infinity()
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// However it should be represented as vec![0; 96] but this
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// would require all signatures to be represented in byte form as opposed to Signature
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let mut empty: Vec<u8> = vec![0; 96];
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// Sets C_flag and B_flag to 1 and all else to 0
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empty[0] += u8::pow(2, 6) + u8::pow(2, 7);
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Signature(RawSignature::from_bytes(&empty).unwrap())
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}
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}
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impl Encodable for Signature {
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fn ssz_append(&self, s: &mut SszStream) {
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s.append_vec(&self.0.as_bytes());
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}
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}
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impl Decodable for Signature {
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fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
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let (sig_bytes, i) = decode_ssz_list(bytes, i)?;
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let raw_sig = RawSignature::from_bytes(&sig_bytes).map_err(|_| DecodeError::TooShort)?;
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Ok((Signature(raw_sig), i))
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}
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}
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impl TreeHash for Signature {
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fn hash_tree_root(&self) -> Vec<u8> {
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hash(&self.0.as_bytes())
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}
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}
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impl Serialize for Signature {
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fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
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where
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S: Serializer,
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{
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serializer.serialize_str(&hex_encode(ssz_encode(self)))
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}
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}
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impl<'de> Deserialize<'de> for Signature {
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fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
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where
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D: Deserializer<'de>,
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{
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let bytes = deserializer.deserialize_str(HexVisitor)?;
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let (pubkey, _) = <_>::ssz_decode(&bytes[..], 0)
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.map_err(|e| serde::de::Error::custom(format!("invalid ssz ({:?})", e)))?;
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Ok(pubkey)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::super::Keypair;
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use super::*;
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use ssz::ssz_encode;
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#[test]
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pub fn test_ssz_round_trip() {
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let keypair = Keypair::random();
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let original = Signature::new(&[42, 42], 0, &keypair.sk);
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let bytes = ssz_encode(&original);
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let (decoded, _) = Signature::ssz_decode(&bytes, 0).unwrap();
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assert_eq!(original, decoded);
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}
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#[test]
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pub fn test_empty_signature() {
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let sig = Signature::empty_signature();
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let sig_as_bytes: Vec<u8> = sig.as_raw().as_bytes();
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assert_eq!(sig_as_bytes.len(), 96);
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for (i, one_byte) in sig_as_bytes.iter().enumerate() {
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if i == 0 {
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assert_eq!(*one_byte, u8::pow(2, 6) + u8::pow(2, 7));
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} else {
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assert_eq!(*one_byte, 0);
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}
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}
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}
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}
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