There are two versions of Repeater available out there and each of them utilizes different copy protection method. Depending on where your copy come from (where it was purchased) it determines the copy protection the license features. So the licenses purchased at:
D16 Group online shop or at one of the official D16's resellers - As other D16's products are protected by a license key file. The instruction how the activation is performed can be found in this FAQ entry.
Slate Digital - Are protected with iLok dongle.