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use ark_crypto_primitives::{CryptoError, Error, CRH as CRHTrait};
use ark_ff::{fields::PrimeField, BigInteger};
use ark_std::{marker::PhantomData, rand::Rng, vec::Vec};
use arkworks_utils::utils::to_field_elements;
#[cfg(feature = "r1cs")]
pub mod constraints;
pub struct CRH<F: PrimeField> {
field: PhantomData<F>,
}
impl<F: PrimeField> CRHTrait for CRH<F> {
type Output = F;
type Parameters = ();
const INPUT_SIZE_BITS: usize = F::BigInt::NUM_LIMBS * 64;
fn setup<R: Rng>(_: &mut R) -> Result<Self::Parameters, Error> {
Ok(())
}
fn evaluate(_: &Self::Parameters, input: &[u8]) -> Result<Self::Output, Error> {
let f_inputs: Vec<F> = to_field_elements(input)?;
assert!(f_inputs.len() == 1);
Ok(f_inputs
.get(0)
.cloned()
.ok_or_else(|| CryptoError::IncorrectInputLength(f_inputs.len()))?)
}
}
#[cfg(test)]
mod test {
use super::CRH;
use ark_crypto_primitives::crh::CRH as CRHTrait;
use ark_ed_on_bn254::Fq;
use ark_ff::to_bytes;
type IdentityCRH = CRH<Fq>;
#[test]
fn should_return_same_data() {
let val = Fq::from(4u64);
let bytes = to_bytes![val].unwrap();
let res = IdentityCRH::evaluate(&(), &bytes).unwrap();
assert_eq!(res, val);
}
}