mirror of https://github.com/zcash/orchard.git
Implements the updated, total definition of MerkleCRH^Orchard
See https://github.com/zcash/zips/pull/530
This commit is contained in:
parent
21b77d6ec5
commit
fd94759fab
58
src/tree.rs
58
src/tree.rs
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@ -17,7 +17,7 @@ use serde::de::{Deserializer, Error};
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use serde::ser::Serializer;
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use serde::{Deserialize, Serialize};
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use std::iter;
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use subtle::{ConstantTimeEq, CtOption};
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use subtle::{Choice, ConditionallySelectable, ConstantTimeEq, CtOption};
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// The uncommitted leaf is defined as pallas::Base(2).
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// <https://zips.z.cash/protocol/protocol.pdf#thmuncommittedorchard>
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@ -170,19 +170,19 @@ fn hash_with_l(l: usize, pair: Pair) -> CtOption<pallas::Base> {
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/// can produce a bottom value which needs to be accounted for in
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/// the production of a Merkle root. Leaf nodes are always wrapped
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/// with the `Some` constructor.
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#[derive(Clone, Debug)]
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pub struct OrchardIncrementalTreeDigest(CtOption<pallas::Base>);
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#[derive(Copy, Clone, Debug)]
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pub struct OrchardIncrementalTreeDigest(pallas::Base);
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impl OrchardIncrementalTreeDigest {
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/// Creates an incremental tree leaf digest from the specified
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/// Orchard extracted note commitment.
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pub fn from_cmx(value: &ExtractedNoteCommitment) -> Self {
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OrchardIncrementalTreeDigest(CtOption::new(**value, 1.into()))
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OrchardIncrementalTreeDigest(**value)
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}
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/// Convert this digest to its canonical byte representation.
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pub fn to_bytes(&self) -> Option<[u8; 32]> {
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<Option<pallas::Base>>::from(self.0).map(|b| b.to_bytes())
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pub fn to_bytes(&self) -> [u8; 32] {
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self.0.to_bytes()
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}
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/// Parses a incremental tree leaf digest from the bytes of
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@ -191,8 +191,7 @@ impl OrchardIncrementalTreeDigest {
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/// Returns the empty `CtOption` if the provided bytes represent
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/// a non-canonical encoding.
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pub fn from_bytes(bytes: &[u8; 32]) -> CtOption<Self> {
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pallas::Base::from_bytes(bytes)
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.map(|b| OrchardIncrementalTreeDigest(CtOption::new(b, 1.into())))
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pallas::Base::from_bytes(bytes).map(OrchardIncrementalTreeDigest)
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}
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}
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@ -215,24 +214,31 @@ impl std::hash::Hash for OrchardIncrementalTreeDigest {
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}
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}
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impl Hashable for OrchardIncrementalTreeDigest {
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fn empty_leaf() -> Self {
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OrchardIncrementalTreeDigest(CtOption::new(*UNCOMMITTED_ORCHARD, 1.into()))
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impl ConditionallySelectable for OrchardIncrementalTreeDigest {
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fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self {
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OrchardIncrementalTreeDigest(pallas::Base::conditional_select(&a.0, &b.0, choice))
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}
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}
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fn combine(altitude: Altitude, left_opt: &Self, right_opt: &Self) -> Self {
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OrchardIncrementalTreeDigest(left_opt.0.and_then(|left| {
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right_opt
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.0
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.and_then(|right| hash_with_l(altitude.into(), Pair { left, right }))
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}))
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impl Hashable for OrchardIncrementalTreeDigest {
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fn empty_leaf() -> Self {
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OrchardIncrementalTreeDigest(*UNCOMMITTED_ORCHARD)
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}
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fn combine(altitude: Altitude, left: &Self, right: &Self) -> Self {
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hash_with_l(
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altitude.into(),
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Pair {
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left: left.0,
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right: right.0,
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},
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)
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.map(OrchardIncrementalTreeDigest)
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.unwrap_or_else(|| OrchardIncrementalTreeDigest(pallas::Base::zero()))
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}
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fn empty_root(altitude: Altitude) -> Self {
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OrchardIncrementalTreeDigest(CtOption::new(
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EMPTY_ROOTS[<usize>::from(altitude)],
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1.into(),
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))
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OrchardIncrementalTreeDigest(EMPTY_ROOTS[<usize>::from(altitude)])
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}
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}
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@ -262,8 +268,6 @@ pub mod testing {
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};
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use std::convert::TryInto;
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#[cfg(test)]
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use subtle::CtOption;
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use crate::{
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constants::MERKLE_DEPTH_ORCHARD,
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@ -419,7 +423,6 @@ pub mod testing {
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assert_eq!(
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OrchardIncrementalTreeDigest::empty_root(Altitude::from(altitude as u8))
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.0
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.unwrap()
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.to_bytes(),
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*tv_root,
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"Empty root mismatch at altitude {}",
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@ -471,14 +474,11 @@ pub mod testing {
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let mut frontier = BridgeFrontier::<OrchardIncrementalTreeDigest, 32>::new();
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for commitment in commitments.iter() {
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let cmx = OrchardIncrementalTreeDigest(CtOption::new(
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pallas::Base::from_bytes(commitment).unwrap(),
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1.into(),
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));
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let cmx = OrchardIncrementalTreeDigest(pallas::Base::from_bytes(commitment).unwrap());
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frontier.append(&cmx);
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}
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assert_eq!(
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frontier.root().0.unwrap(),
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frontier.root().0,
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pallas::Base::from_bytes(&anchor).unwrap()
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);
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}
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