How to create an activator + keygen for my .Net app?

Question

I want to create an app that is only runnable on one machine (PC). The software should be activated through an activation key (the user sends me the activation serial and I will send him the code). Any suggestions on how should I do this? Thanks.

Answer 1

In addition to the answers provided in link, most simple solution I met was actually to recover ProcessorID and hash it with some encryption algo with Start and End date, if there is any date limit management.

Just to give a basic idea:

Good: It's easy to develop and it's free.

Bad: if it depends on start and end date, you basically lookup on PC, so to trick the control it's enough to put your Computer's date back.