penumbra_keys/prf.rs
use ark_ff::PrimeField;
pub fn expand(label: &'static [u8; 16], key: &[u8], input: &[u8]) -> blake2b_simd::Hash {
blake2b_simd::Params::new()
.personal(label)
.key(key)
.hash(input)
}
pub fn expand_ff<F: PrimeField>(label: &'static [u8; 16], key: &[u8], input: &[u8]) -> F {
F::from_le_bytes_mod_order(expand(label, key, input).as_bytes())
}