Is there any properties in the Product object that is protected from unauthenticated query?

My App needs to save some unique information for each product. This information should be secret and can only be accessed from my app.

I am thinking two ways to implement this, 1. use a Database to store such information for each product, which I don’t want to choose because I have to maintain a large database with all the products; 2. store such information to a property of the Product object. However, it seems that all the properties of a product can be easily accessed by adding a .json at the end of the product, for example, https://mystore.myshopify.com/products/dark-brook.json. I wonder if there is a way to create a property to the Product object that can only be accessed with authenticated query?