If you want to restrict access to your nodeStorage server to a small group of people, you can create a file containing the Twitter screen-names of the whitelisted users, and tell your nodeStorage server about it. This howto explains what to do.
The whitelist is a JSON file that contains the names of the whitelisted users. Here's an example. It must be in a place where your nodeStorage server can access it over HTTP.
Set up an environment variable called urlUserWhitelist. Its value is the address of the JSON file.
Be careful that the JSON is syntactically valid. Test it with jsonlint if you're not sure.
The nodeStorage server reads the whitelist once a minute. You don't have to restart the server to make your changes effective. Just wait a minute.
If you've established a whitelist, and a user is not on it, they will not be able to use the server to store data.