redjubjub/src/hash.rs

31 lines
749 B
Rust

use crate::Scalar;
use blake2b_simd::{Params, State};
/// Provides H^star, the hash-to-scalar function used by RedJubjub.
pub struct HStar {
state: State,
}
impl Default for HStar {
fn default() -> Self {
let state = Params::new()
.hash_length(64)
.personal(b"Zcash_RedJubjubH")
.to_state();
Self { state }
}
}
impl HStar {
/// Add `data` to the hash, and return `Self` for chaining.
pub fn update(&mut self, data: impl AsRef<[u8]>) -> &mut Self {
self.state.update(data.as_ref());
self
}
/// Consume `self` to compute the hash output.
pub fn finalize(&self) -> Scalar {
Scalar::from_bytes_wide(self.state.finalize().as_array())
}
}