mirror of https://github.com/zcash/halo2.git
poseidon: Replace the `Duplex` struct with a `Sponge` struct
The `Sponge` struct's API correctly enforces the properties of a sponge: it can absorb an arbitrary number of elements, and then squeeze an arbitrary number of elements, but cannot absorb after it has squeezed. Co-authored-by: ying tong <yingtong@z.cash>
This commit is contained in:
parent
b827298d42
commit
9f654005c7
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@ -3,6 +3,7 @@
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use std::array;
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use std::convert::TryInto;
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use std::fmt;
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use std::marker::PhantomData;
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use halo2::{
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arithmetic::FieldExt,
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@ -13,7 +14,9 @@ use halo2::{
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mod pow5;
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pub use pow5::{Pow5Chip, Pow5Config, StateWord};
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use crate::primitives::poseidon::{ConstantLength, Domain, Spec, Sponge, SpongeRate, State};
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use crate::primitives::poseidon::{
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Absorbing, ConstantLength, Domain, Spec, SpongeMode, SpongeRate, Squeezing, State,
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};
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/// The set of circuit instructions required to use the Poseidon permutation.
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pub trait PoseidonInstructions<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RATE: usize>:
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@ -30,10 +33,10 @@ pub trait PoseidonInstructions<F: FieldExt, S: Spec<F, T, RATE>, const T: usize,
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) -> Result<State<Self::Word, T>, Error>;
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}
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/// The set of circuit instructions required to use the [`Duplex`] and [`Hash`] gadgets.
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/// The set of circuit instructions required to use the [`Sponge`] and [`Hash`] gadgets.
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///
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/// [`Hash`]: self::Hash
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pub trait PoseidonDuplexInstructions<
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pub trait PoseidonSpongeInstructions<
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F: FieldExt,
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S: Spec<F, T, RATE>,
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const T: usize,
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@ -91,9 +94,9 @@ impl<
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}
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}
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fn poseidon_duplex<
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fn poseidon_sponge<
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F: FieldExt,
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PoseidonChip: PoseidonDuplexInstructions<F, S, T, RATE>,
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PoseidonChip: PoseidonSpongeInstructions<F, S, T, RATE>,
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S: Spec<F, T, RATE>,
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D: Domain<F, T, RATE>,
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const T: usize,
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@ -110,30 +113,32 @@ fn poseidon_duplex<
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Ok(PoseidonChip::get_output(state))
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}
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/// A Poseidon duplex sponge.
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/// A Poseidon sponge.
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#[derive(Debug)]
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pub struct Duplex<
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pub struct Sponge<
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F: FieldExt,
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PoseidonChip: PoseidonDuplexInstructions<F, S, T, RATE>,
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PoseidonChip: PoseidonSpongeInstructions<F, S, T, RATE>,
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S: Spec<F, T, RATE>,
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M: SpongeMode,
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D: Domain<F, T, RATE>,
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const T: usize,
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const RATE: usize,
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> {
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chip: PoseidonChip,
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sponge: Sponge<PoseidonChip::Word, RATE>,
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mode: M,
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state: State<PoseidonChip::Word, T>,
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domain: D,
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_marker: PhantomData<M>,
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}
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impl<
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F: FieldExt,
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PoseidonChip: PoseidonDuplexInstructions<F, S, T, RATE>,
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PoseidonChip: PoseidonSpongeInstructions<F, S, T, RATE>,
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S: Spec<F, T, RATE>,
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D: Domain<F, T, RATE>,
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const T: usize,
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const RATE: usize,
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> Duplex<F, PoseidonChip, S, D, T, RATE>
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> Sponge<F, PoseidonChip, S, Absorbing<PoseidonChip::Word, RATE>, D, T, RATE>
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{
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/// Constructs a new duplex sponge for the given Poseidon specification.
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pub fn new(
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@ -142,9 +147,9 @@ impl<
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domain: D,
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) -> Result<Self, Error> {
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chip.initial_state(&mut layouter, &domain)
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.map(|state| Duplex {
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.map(|state| Sponge {
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chip,
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sponge: Sponge::Absorbing(
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mode: Absorbing(
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(0..RATE)
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.map(|_| None)
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.collect::<Vec<_>>()
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@ -153,6 +158,7 @@ impl<
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),
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state,
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domain,
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_marker: PhantomData::default(),
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})
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}
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@ -162,9 +168,7 @@ impl<
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mut layouter: impl Layouter<F>,
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value: AssignedCell<F, F>,
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) -> Result<(), Error> {
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match self.sponge {
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Sponge::Absorbing(ref mut input) => {
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for entry in input.iter_mut() {
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for entry in self.mode.0.iter_mut() {
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if entry.is_none() {
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*entry = Some(value.into());
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return Ok(());
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@ -172,74 +176,89 @@ impl<
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}
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// We've already absorbed as many elements as we can
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let _ = poseidon_duplex(
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let _ = poseidon_sponge(
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&self.chip,
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layouter.namespace(|| "PoseidonDuplex"),
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layouter.namespace(|| "PoseidonSponge"),
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&self.domain,
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&mut self.state,
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input,
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&self.mode.0,
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)?;
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self.sponge = Sponge::absorb(value.into());
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}
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Sponge::Squeezing(_) => {
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// Drop the remaining output elements
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self.sponge = Sponge::absorb(value.into());
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}
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}
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self.mode = Absorbing::init_with(value.into());
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Ok(())
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}
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/// Transitions the sponge into its squeezing state.
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#[allow(clippy::type_complexity)]
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pub fn finish_absorbing(
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mut self,
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mut layouter: impl Layouter<F>,
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) -> Result<Sponge<F, PoseidonChip, S, Squeezing<PoseidonChip::Word, RATE>, D, T, RATE>, Error>
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{
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let mode = Squeezing(poseidon_sponge(
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&self.chip,
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layouter.namespace(|| "PoseidonSponge"),
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&self.domain,
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&mut self.state,
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&self.mode.0,
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)?);
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Ok(Sponge {
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chip: self.chip,
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mode,
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state: self.state,
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domain: self.domain,
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_marker: PhantomData::default(),
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})
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}
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}
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impl<
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F: FieldExt,
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PoseidonChip: PoseidonSpongeInstructions<F, S, T, RATE>,
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S: Spec<F, T, RATE>,
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D: Domain<F, T, RATE>,
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const T: usize,
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const RATE: usize,
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> Sponge<F, PoseidonChip, S, Squeezing<PoseidonChip::Word, RATE>, D, T, RATE>
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{
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/// Squeezes an element from the sponge.
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pub fn squeeze(&mut self, mut layouter: impl Layouter<F>) -> Result<AssignedCell<F, F>, Error> {
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loop {
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match self.sponge {
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Sponge::Absorbing(ref input) => {
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self.sponge = Sponge::Squeezing(poseidon_duplex(
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&self.chip,
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layouter.namespace(|| "PoseidonDuplex"),
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&self.domain,
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&mut self.state,
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input,
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)?);
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}
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Sponge::Squeezing(ref mut output) => {
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for entry in output.iter_mut() {
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for entry in self.mode.0.iter_mut() {
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if let Some(inner) = entry.take() {
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return Ok(inner.into());
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}
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}
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// We've already squeezed out all available elements
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self.sponge = Sponge::Absorbing(
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(0..RATE)
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.map(|_| None)
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.collect::<Vec<_>>()
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.try_into()
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.unwrap(),
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);
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}
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}
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self.mode = Squeezing(poseidon_sponge(
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&self.chip,
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layouter.namespace(|| "PoseidonSponge"),
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&self.domain,
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&mut self.state,
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&self.mode.0,
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)?);
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}
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}
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}
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/// A Poseidon hash function, built around a duplex sponge.
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/// A Poseidon hash function, built around a sponge.
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#[derive(Debug)]
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pub struct Hash<
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F: FieldExt,
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PoseidonChip: PoseidonDuplexInstructions<F, S, T, RATE>,
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PoseidonChip: PoseidonSpongeInstructions<F, S, T, RATE>,
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S: Spec<F, T, RATE>,
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D: Domain<F, T, RATE>,
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const T: usize,
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const RATE: usize,
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> {
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duplex: Duplex<F, PoseidonChip, S, D, T, RATE>,
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sponge: Sponge<F, PoseidonChip, S, Absorbing<PoseidonChip::Word, RATE>, D, T, RATE>,
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}
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impl<
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F: FieldExt,
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PoseidonChip: PoseidonDuplexInstructions<F, S, T, RATE>,
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PoseidonChip: PoseidonSpongeInstructions<F, S, T, RATE>,
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S: Spec<F, T, RATE>,
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D: Domain<F, T, RATE>,
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const T: usize,
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{
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/// Initializes a new hasher.
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pub fn init(chip: PoseidonChip, layouter: impl Layouter<F>, domain: D) -> Result<Self, Error> {
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Duplex::new(chip, layouter, domain).map(|duplex| Hash { duplex })
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Sponge::new(chip, layouter, domain).map(|sponge| Hash { sponge })
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}
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}
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impl<
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F: FieldExt,
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PoseidonChip: PoseidonDuplexInstructions<F, S, T, RATE>,
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PoseidonChip: PoseidonSpongeInstructions<F, S, T, RATE>,
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S: Spec<F, T, RATE>,
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const T: usize,
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const RATE: usize,
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message: [AssignedCell<F, F>; L],
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) -> Result<AssignedCell<F, F>, Error> {
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for (i, value) in array::IntoIter::new(message).enumerate() {
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self.duplex
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self.sponge
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.absorb(layouter.namespace(|| format!("absorb_{}", i)), value)?;
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}
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self.duplex.squeeze(layouter.namespace(|| "squeeze"))
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self.sponge
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.finish_absorbing(layouter.namespace(|| "finish absorbing"))?
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.squeeze(layouter.namespace(|| "squeeze"))
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}
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}
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@ -8,7 +8,7 @@ use halo2::{
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poly::Rotation,
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};
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use super::{PoseidonDuplexInstructions, PoseidonInstructions};
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use super::{PoseidonInstructions, PoseidonSpongeInstructions};
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use crate::circuit::gadget::utilities::Var;
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use crate::primitives::poseidon::{Domain, Mds, Spec, SpongeRate, State};
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@ -269,7 +269,7 @@ impl<F: FieldExt, S: Spec<F, WIDTH, RATE>, const WIDTH: usize, const RATE: usize
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}
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impl<F: FieldExt, S: Spec<F, WIDTH, RATE>, const WIDTH: usize, const RATE: usize>
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PoseidonDuplexInstructions<F, S, WIDTH, RATE> for Pow5Chip<F, WIDTH, RATE>
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PoseidonSpongeInstructions<F, S, WIDTH, RATE> for Pow5Chip<F, WIDTH, RATE>
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{
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fn initial_state(
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&self,
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@ -24,7 +24,7 @@ use grain::SboxType;
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/// The type used to hold permutation state.
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pub(crate) type State<F, const T: usize> = [F; T];
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/// The type used to hold duplex sponge state.
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/// The type used to hold sponge rate.
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pub(crate) type SpongeRate<F, const RATE: usize> = [Option<F>; RATE];
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/// The type used to hold the MDS matrix and its inverse.
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@ -124,7 +124,7 @@ pub(crate) fn permute<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RA
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});
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}
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fn poseidon_duplex<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RATE: usize>(
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fn poseidon_sponge<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RATE: usize>(
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state: &mut State<F, T>,
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input: &SpongeRate<F, RATE>,
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pad_and_add: &dyn Fn(&mut State<F, T>, &SpongeRate<F, RATE>),
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@ -142,48 +142,65 @@ fn poseidon_duplex<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RATE:
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output
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}
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#[derive(Debug)]
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pub(crate) enum Sponge<F, const RATE: usize> {
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Absorbing(SpongeRate<F, RATE>),
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Squeezing(SpongeRate<F, RATE>),
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}
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/// The state of the [`Sponge`].
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// TODO: Seal this trait?
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pub trait SpongeMode {}
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impl<F: fmt::Debug, const RATE: usize> Sponge<F, RATE> {
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pub(crate) fn absorb(val: F) -> Self {
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let mut input: [Option<F>; RATE] = (0..RATE)
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.map(|_| None)
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/// The absorbing state of the [`Sponge`].
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#[derive(Debug)]
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pub struct Absorbing<F, const RATE: usize>(pub(crate) SpongeRate<F, RATE>);
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/// The squeezing state of the [`Sponge`].
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#[derive(Debug)]
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pub struct Squeezing<F, const RATE: usize>(pub(crate) SpongeRate<F, RATE>);
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impl<F, const RATE: usize> SpongeMode for Absorbing<F, RATE> {}
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impl<F, const RATE: usize> SpongeMode for Squeezing<F, RATE> {}
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impl<F: fmt::Debug, const RATE: usize> Absorbing<F, RATE> {
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pub(crate) fn init_with(val: F) -> Self {
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Self(
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iter::once(Some(val))
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.chain((1..RATE).map(|_| None))
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.collect::<Vec<_>>()
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.try_into()
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.unwrap();
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input[0] = Some(val);
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Sponge::Absorbing(input)
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.unwrap(),
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)
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}
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}
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/// A Poseidon duplex sponge.
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pub(crate) struct Duplex<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RATE: usize> {
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sponge: Sponge<F, RATE>,
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/// A Poseidon sponge.
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pub(crate) struct Sponge<
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F: FieldExt,
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S: Spec<F, T, RATE>,
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M: SpongeMode,
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const T: usize,
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const RATE: usize,
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> {
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mode: M,
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state: State<F, T>,
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pad_and_add: Box<dyn Fn(&mut State<F, T>, &SpongeRate<F, RATE>)>,
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mds_matrix: Mds<F, T>,
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round_constants: Vec<[F; T]>,
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_marker: PhantomData<S>,
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_marker: PhantomData<(S, M)>,
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}
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impl<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RATE: usize> Duplex<F, S, T, RATE> {
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/// Constructs a new duplex sponge for the given Poseidon specification.
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impl<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RATE: usize>
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Sponge<F, S, Absorbing<F, RATE>, T, RATE>
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{
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/// Constructs a new sponge for the given Poseidon specification.
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pub(crate) fn new(
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initial_capacity_element: F,
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pad_and_add: Box<dyn Fn(&mut State<F, T>, &SpongeRate<F, RATE>)>,
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) -> Self {
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let (round_constants, mds_matrix, _) = S::constants();
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let input = [None; RATE];
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let mode = Absorbing([None; RATE]);
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let mut state = [F::zero(); T];
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state[RATE] = initial_capacity_element;
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Duplex {
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sponge: Sponge::Absorbing(input),
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Sponge {
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mode,
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state,
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pad_and_add,
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mds_matrix,
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|
@ -194,9 +211,7 @@ impl<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RATE: usize> Duplex
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/// Absorbs an element into the sponge.
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pub(crate) fn absorb(&mut self, value: F) {
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match self.sponge {
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Sponge::Absorbing(ref mut input) => {
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for entry in input.iter_mut() {
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for entry in self.mode.0.iter_mut() {
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if entry.is_none() {
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*entry = Some(value);
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return;
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|
@ -204,46 +219,57 @@ impl<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RATE: usize> Duplex
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}
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// We've already absorbed as many elements as we can
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let _ = poseidon_duplex::<F, S, T, RATE>(
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let _ = poseidon_sponge::<F, S, T, RATE>(
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&mut self.state,
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input,
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&self.mode.0,
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&self.pad_and_add,
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&self.mds_matrix,
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&self.round_constants,
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);
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self.sponge = Sponge::absorb(value);
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}
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Sponge::Squeezing(_) => {
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// Drop the remaining output elements
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self.sponge = Sponge::absorb(value);
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}
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}
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self.mode = Absorbing::init_with(value);
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}
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/// Squeezes an element from the sponge.
|
||||
pub(crate) fn squeeze(&mut self) -> F {
|
||||
loop {
|
||||
match self.sponge {
|
||||
Sponge::Absorbing(ref input) => {
|
||||
self.sponge = Sponge::Squeezing(poseidon_duplex::<F, S, T, RATE>(
|
||||
/// Transitions the sponge into its squeezing state.
|
||||
pub(crate) fn finish_absorbing(mut self) -> Sponge<F, S, Squeezing<F, RATE>, T, RATE> {
|
||||
let mode = Squeezing(poseidon_sponge::<F, S, T, RATE>(
|
||||
&mut self.state,
|
||||
input,
|
||||
&self.mode.0,
|
||||
&self.pad_and_add,
|
||||
&self.mds_matrix,
|
||||
&self.round_constants,
|
||||
));
|
||||
|
||||
Sponge {
|
||||
mode,
|
||||
state: self.state,
|
||||
pad_and_add: self.pad_and_add,
|
||||
mds_matrix: self.mds_matrix,
|
||||
round_constants: self.round_constants,
|
||||
_marker: PhantomData::default(),
|
||||
}
|
||||
Sponge::Squeezing(ref mut output) => {
|
||||
for entry in output.iter_mut() {
|
||||
}
|
||||
}
|
||||
|
||||
impl<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RATE: usize>
|
||||
Sponge<F, S, Squeezing<F, RATE>, T, RATE>
|
||||
{
|
||||
/// Squeezes an element from the sponge.
|
||||
pub(crate) fn squeeze(&mut self) -> F {
|
||||
loop {
|
||||
for entry in self.mode.0.iter_mut() {
|
||||
if let Some(e) = entry.take() {
|
||||
return e;
|
||||
}
|
||||
}
|
||||
|
||||
// We've already squeezed out all available elements
|
||||
self.sponge = Sponge::Absorbing([None; RATE]);
|
||||
}
|
||||
}
|
||||
self.mode = Squeezing(poseidon_sponge::<F, S, T, RATE>(
|
||||
&mut self.state,
|
||||
&self.mode.0,
|
||||
&self.pad_and_add,
|
||||
&self.mds_matrix,
|
||||
&self.round_constants,
|
||||
));
|
||||
}
|
||||
}
|
||||
}
|
||||
|
@ -301,7 +327,7 @@ impl<F: FieldExt, const T: usize, const RATE: usize, const L: usize> Domain<F, T
|
|||
}
|
||||
}
|
||||
|
||||
/// A Poseidon hash function, built around a duplex sponge.
|
||||
/// A Poseidon hash function, built around a sponge.
|
||||
pub struct Hash<
|
||||
F: FieldExt,
|
||||
S: Spec<F, T, RATE>,
|
||||
|
@ -309,7 +335,7 @@ pub struct Hash<
|
|||
const T: usize,
|
||||
const RATE: usize,
|
||||
> {
|
||||
duplex: Duplex<F, S, T, RATE>,
|
||||
sponge: Sponge<F, S, Absorbing<F, RATE>, T, RATE>,
|
||||
domain: D,
|
||||
}
|
||||
|
||||
|
@ -343,7 +369,7 @@ impl<
|
|||
/// Initializes a new hasher.
|
||||
pub fn init(domain: D) -> Self {
|
||||
Hash {
|
||||
duplex: Duplex::new(domain.initial_capacity_element(), domain.pad_and_add()),
|
||||
sponge: Sponge::new(domain.initial_capacity_element(), domain.pad_and_add()),
|
||||
domain,
|
||||
}
|
||||
}
|
||||
|
@ -355,9 +381,9 @@ impl<F: FieldExt, S: Spec<F, T, RATE>, const T: usize, const RATE: usize, const
|
|||
/// Hashes the given input.
|
||||
pub fn hash(mut self, message: [F; L]) -> F {
|
||||
for value in array::IntoIter::new(message) {
|
||||
self.duplex.absorb(value);
|
||||
self.sponge.absorb(value);
|
||||
}
|
||||
self.duplex.squeeze()
|
||||
self.sponge.finish_absorbing().squeeze()
|
||||
}
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in New Issue