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use crate::{
crh::{PedersenCRH, PedersenCRHParameters},
errors::CRHError,
traits::{CRHParameters, CRH},
};
use snarkvm_curves::{AffineCurve, Group, ProjectiveCurve};
use snarkvm_fields::{ConstraintFieldError, Field, ToConstraintField};
use rand::Rng;
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub struct PedersenCompressedCRH<G: Group + ProjectiveCurve, const NUM_WINDOWS: usize, const WINDOW_SIZE: usize> {
pub parameters: PedersenCRHParameters<G, NUM_WINDOWS, WINDOW_SIZE>,
}
impl<G: Group + ProjectiveCurve, const NUM_WINDOWS: usize, const WINDOW_SIZE: usize> CRH
for PedersenCompressedCRH<G, NUM_WINDOWS, WINDOW_SIZE>
{
type Output = <G::Affine as AffineCurve>::BaseField;
type Parameters = PedersenCRHParameters<G, NUM_WINDOWS, WINDOW_SIZE>;
const INPUT_SIZE_BITS: usize = WINDOW_SIZE * NUM_WINDOWS;
fn setup<R: Rng>(rng: &mut R) -> Self {
Self {
parameters: PedersenCRHParameters::setup(rng),
}
}
fn hash(&self, input: &[u8]) -> Result<Self::Output, CRHError> {
let crh = PedersenCRH::<G, NUM_WINDOWS, WINDOW_SIZE> {
parameters: self.parameters.clone(),
};
let output = crh.hash(input)?;
let affine = output.into_affine();
debug_assert!(affine.is_in_correct_subgroup_assuming_on_curve());
Ok(affine.to_x_coordinate())
}
fn parameters(&self) -> &Self::Parameters {
&self.parameters
}
}
impl<G: Group + ProjectiveCurve, const NUM_WINDOWS: usize, const WINDOW_SIZE: usize>
From<PedersenCRHParameters<G, NUM_WINDOWS, WINDOW_SIZE>> for PedersenCompressedCRH<G, NUM_WINDOWS, WINDOW_SIZE>
{
fn from(parameters: PedersenCRHParameters<G, NUM_WINDOWS, WINDOW_SIZE>) -> Self {
Self { parameters }
}
}
impl<F: Field, G: Group + ProjectiveCurve + ToConstraintField<F>, const NUM_WINDOWS: usize, const WINDOW_SIZE: usize>
ToConstraintField<F> for PedersenCompressedCRH<G, NUM_WINDOWS, WINDOW_SIZE>
{
#[inline]
fn to_field_elements(&self) -> Result<Vec<F>, ConstraintFieldError> {
self.parameters.to_field_elements()
}
}