public byte[] hmac(byte[] key, byte[] bytes) throws InvalidKeyException {
        mac.init(new SecretKeySpec(key, mac.getAlgorithm()));
        return mac.doFinal(bytes);
    }
Scram message salt and hash functions defined in <a href="https://tools.ietf.org/html/rfc5802">RFC 5802</a>.
clients/src/main/java/org/apache/kafka/common/security/scram/internals/ScramFormatter.java