Implementing License manager for published games

Are there any tools/plugins available to implement some sort of a licensing tool in a game created in Unreal?.
I would like to implement a game that lets the player play for a week or so and after one week it should start asking to purchase the game.
The user should be able to enter a license key (received via email) and the restrictions would be removed.
I would prefer not to do an online verification, but would be open to do it if it is really needed.