ark-r1cs-std/crypto-primitives/src/commitment/blake2s/mod.rs

use super::CommitmentScheme;
use blake2::Blake2s as b2s;
use digest::Digest;
use crate::Error;
use rand::Rng;

pub struct Blake2sCommitment;

impl CommitmentScheme for Blake2sCommitment {
    type Parameters = ();
    type Randomness = [u8; 32];
    type Output = [u8; 32];

    fn setup<R: Rng>(_: &mut R) -> Result<Self::Parameters, Error> {
        Ok(())
    }

    fn commit(
        _: &Self::Parameters,
        input: &[u8],
        randomness: &Self::Randomness,
    ) -> Result<Self::Output, Error> {
        let mut h = b2s::new();
        h.input(input);
        h.input(randomness.as_ref());
        let mut result = [0u8; 32];
        result.copy_from_slice(&h.result());
        Ok(result)
    }
}