Passcode Protect Pages Within Members App

Hi,

We're looking to create a secure client area for a site where logged in users can access secure content pages.

The problem we're facing is that the client requires that the user enters a code to prove they have purchased a physical product before being able to see the content for a specific product within the client area.

So once logged in they click on a product title and enter a passcode after which they can access the content for that product.

Are there any apps or recommendations that would help us achieve that?

Thanks a lot