Zebra/zebra-chain/src/sprout/commitment.rs

66 lines
1.6 KiB
Rust

//! Sprout commitment types.
use sha2::{Digest, Sha256};
use crate::fmt::HexDebug;
use super::note::Note;
/// The randomness used in the Pedersen Hash for note commitment.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
#[cfg_attr(
any(test, feature = "proptest-impl"),
derive(proptest_derive::Arbitrary)
)]
pub struct CommitmentRandomness(pub HexDebug<[u8; 32]>);
impl AsRef<[u8]> for CommitmentRandomness {
fn as_ref(&self) -> &[u8] {
self.0.as_ref()
}
}
/// Note commitments for the output notes.
#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Eq, Serialize)]
#[cfg_attr(
any(test, feature = "proptest-impl"),
derive(proptest_derive::Arbitrary)
)]
pub struct NoteCommitment(pub(crate) HexDebug<[u8; 32]>);
impl From<[u8; 32]> for NoteCommitment {
fn from(bytes: [u8; 32]) -> Self {
Self(bytes.into())
}
}
impl From<Note> for NoteCommitment {
/// NoteCommit_rcm^Sprout(a_pk, v, rho)
///
/// <https://zips.z.cash/protocol/protocol.pdf#concretesproutnotecommit>
fn from(note: Note) -> NoteCommitment {
let leading_byte: u8 = 0xB0;
let mut hasher = Sha256::default();
hasher.update([leading_byte]);
hasher.update(note.paying_key);
hasher.update(note.value.to_bytes());
hasher.update(note.rho);
hasher.update(note.rcm);
let commitment: [u8; 32] = hasher.finalize().into();
NoteCommitment(commitment.into())
}
}
impl From<NoteCommitment> for [u8; 32] {
fn from(cm: NoteCommitment) -> [u8; 32] {
*cm.0
}
}
impl From<&NoteCommitment> for [u8; 32] {
fn from(cm: &NoteCommitment) -> [u8; 32] {
*cm.0
}
}