Access Code Structuring For Enterprise Software

Question

I have just finished an iOS application for a company that will be sold commercially to schools and other organizations for a flat rate with an access code. I was wondering if anyone has had any previous experience with access codes, and what would be the best way to implement this design in to the app? I received equity in the company as well, so I would like to make the best decisions to advise to the owner.

Say, for example, the Main County Public Schools purchased access to the software. How would I prevent the access code from being shared? Would a device limit work? But what would prevent the users from sharing the access code to Non-Main County students?

Note: I'm not asking for code, but more of a discussion on the best practices of implementation.

Answer 1

Your situation is not different from that of any licensing situation for a group of users. One way is generate a unique identifier per registered machine, using fingerprints, a hardware dongle etc. This identifier becomes the input to a private key signature computed on your secure server, and the signature is stored on the registered machine to be verified at run time, using the same unique identifier and a corresponding public key stored in the software. The other options are a license server, which can keep track of how many licenses are in use, or the trust model, where clients obey the terms of an agreement to avoid lawsuits.