I have to do a project like a subscription manager. Ideally this should work like RedHat subscriptions. I'm having a hard time figuring out how it was implemented. How do they manage to avoid a customer modifying the subscription components in a operating system and getting free patches to more instances that they have in the subscription? (ie they have X instances in the subscription but customer runs Y number of instances and Y > X.)
Does anyone know how it works, the cryptography of the system, etc.? Any open research articles, documents?