use crate::{keys::hash, SecretKey, StealthAddress, ViewKey};
use dusk_jubjub::{JubJubAffine, JubJubExtended, JubJubScalar};
#[cfg(feature = "rkyv-impl")]
use rkyv::{Archive, Deserialize, Serialize};
use dusk_bytes::{DeserializableSlice, Error, Serializable};
use dusk_jubjub::GENERATOR_EXTENDED;
use subtle::{Choice, ConstantTimeEq};
#[derive(Debug, Clone, Copy)]
#[cfg_attr(
feature = "rkyv-impl",
derive(Archive, Serialize, Deserialize),
archive_attr(derive(bytecheck::CheckBytes))
)]
pub struct PublicKey {
A: JubJubExtended,
B: JubJubExtended,
}
impl PublicKey {
pub fn new(A: JubJubExtended, B: JubJubExtended) -> Self {
Self { A, B }
}
pub fn A(&self) -> &JubJubExtended {
&self.A
}
pub fn B(&self) -> &JubJubExtended {
&self.B
}
pub fn gen_stealth_address(&self, r: &JubJubScalar) -> StealthAddress {
let G = GENERATOR_EXTENDED;
let R = G * r;
let rA = self.A * r;
let rA = hash(&rA);
let rA = G * rA;
let note_pk = rA + self.B;
let note_pk = note_pk.into();
StealthAddress { R, note_pk }
}
}
impl ConstantTimeEq for PublicKey {
fn ct_eq(&self, other: &Self) -> Choice {
self.A.ct_eq(&other.A) & self.B.ct_eq(&other.B)
}
}
impl PartialEq for PublicKey {
fn eq(&self, other: &Self) -> bool {
self.ct_eq(other).into()
}
}
impl Eq for PublicKey {}
impl From<&SecretKey> for PublicKey {
fn from(sk: &SecretKey) -> Self {
let A = GENERATOR_EXTENDED * sk.a();
let B = GENERATOR_EXTENDED * sk.b();
PublicKey::new(A, B)
}
}
impl From<ViewKey> for PublicKey {
fn from(vk: ViewKey) -> Self {
Self::from(&vk)
}
}
impl From<&ViewKey> for PublicKey {
fn from(vk: &ViewKey) -> Self {
let A = GENERATOR_EXTENDED * vk.a();
PublicKey::new(A, *vk.B())
}
}
impl Serializable<64> for PublicKey {
type Error = Error;
fn to_bytes(&self) -> [u8; Self::SIZE] {
let mut bytes = [0u8; Self::SIZE];
bytes[..32].copy_from_slice(&JubJubAffine::from(self.A).to_bytes());
bytes[32..].copy_from_slice(&JubJubAffine::from(self.B).to_bytes());
bytes
}
fn from_bytes(bytes: &[u8; Self::SIZE]) -> Result<Self, Self::Error> {
let A = JubJubExtended::from(JubJubAffine::from_slice(&bytes[..32])?);
let B = JubJubExtended::from(JubJubAffine::from_slice(&bytes[32..])?);
Ok(Self { A, B })
}
}