Ask HN: Best resources on online software licensing?

TLDR; Do you have resources about licensing your software online?

I'm currently developing an application where we need to implement online activation and licensing. The process would enable a totally independent installation and a continuous check (once a day for example, or on startup, depending on the type of application).

Browsing over the internet I've found numerous companies offering this as a service, but all of them seem to be relatively old and don't present themselves as very trustworthy to me. This leads me to believe I have to develop it myself. Given that I have no experience in this exact manner, I was wondering if there are some good resources on this, for example describing the Microsoft Activation process, Adobe or similar applications.

Preferably it would cover from a high level to, for example, a description of how the API would work. Obviously the details will always be different, but it would be nice to see how other companies have worked this one out to prevent myself from reinventing the wheel.

For us it would be an application running in the .NET environment, but for resources it doesn't matter that much if it would be for a different environment.