public byte[] serverSignature(byte[] serverKey, ClientFirstMessage clientFirstMessage, ServerFirstMessage serverFirstMessage, ClientFinalMessage clientFinalMessage) throws InvalidKeyException {
        byte[] authMessage = authMessage(clientFirstMessage, serverFirstMessage, clientFinalMessage);
        return hmac(serverKey, authMessage);
    }
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