@Override
        public byte[] evaluateResponse(final byte[] clientResponse) throws AuthenticationException {
            logger.debug("evaluateResponse() length: " + clientResponse.length);
            byte[] response;
            try {
                response = saslServer.evaluateResponse(clientResponse);
            } catch (Exception e) {
                logger.warn("Sasl krb5 evaluateResponse failed: " + e);
                throw new AuthenticationException(e);
            }
            return response;
        }
Called once on server startup with the authentication.config from the *.yaml file
gremlin-server/src/main/java/org/apache/tinkerpop/gremlin/server/auth/Krb5Authenticator.java