I am developing a product that uses custom hardware with accompanying software. It requires additional components which are sold separately to make the overall application work.
Using these additional components makes it similar to a razor-blade style business model (see http://www.investopedia.com/terms/r/razor-razorblademodel.asp). The intention is to secure the product so that only the allowed add-on components can be used with the main product.
The technology to do this in the application is with RFID and embedding information inside the RFID tags.
To prevent easy workarounds, an approach using symmetric encryption would work however, I'm concerned with an approach that uses the same private key in every case.
Therefore I'm interested in any approaches or tips with key management for this type of application.