presto-main/src/main/java/io/prestosql/server/InternalAuthenticationManager.java/InternalAuthenticationManager/InternalAuthenticationManager
class InternalAuthenticationManager:    public InternalAuthenticationManager(Optional<String> sharedSecret, String nodeId)
    {
        if (sharedSecret.isPresent()) {
            byte[] hmac = Hashing.sha256().hashString(sharedSecret.get(), UTF_8).asBytes();
            this.jwtParser = Optional.of(jwt -> parseJwt(hmac, jwt));
            this.jwtGenerator = Optional.of(() -> generateJwt(hmac, nodeId));
        }
        else {
            this.jwtParser = Optional.empty();
            this.jwtGenerator = Optional.empty();
        }
    }