Adobe / Fastspring Licensing Scheme

I'm about to launch my Adobe InDesign extension via the Adobe Exchange Marketplace, but I'm concerned about security: I'd like to know what copy protection or license scheme is used by Adobe/Fastspring? I would like to make sure that the plugin can only be used by the buyer. And if the customer stops paying for his subscription, the license will eventually expire and be locked. Thanks a lot for your help. I await your reply.