pub fn hkdf_sha256<S: Sha256Provider>(
sha: &S,
ikm: &[u8],
salt: &[u8],
info: &[u8],
okm: &mut [u8],
)Expand description
HKDF-SHA256 over any Sha256Provider, for callers that have no
CryptoEngine — the entropy pool derives keys before any AES
provider exists.