crypto_hash function
Implementation
void crypto_hash(Uint8List out, Uint8List m, int n, String hashMode) {
var digest = hashMode == 'sha512' ? pc.SHA512Digest() : pc.KeccakDigest(512);
var copied = Uint8List(n);
copied.setRange(0, n, m);
digest.update(copied, 0, copied.length);
digest.doFinal(out, 0);
}