>>If Refox somehow enforced a label with your name on the resulting exe or prg, you could tell that there's a difference, just like when you buy a POS / accounting system and your company's name shows up on all your reports & invoices for example.. it would be clear you'll need another license for another company / user..

For itself, Refox does "brand" the installation for the licensee and their PC so it might be possible for Jan to include some sort of branding for Refoxed apps.

Leonid Lepin's Defox protection system already includes a registration scheme in Assembly Language so your customers need to "register" with you to get an unlock key for your Defoxed software.

You still need VFP code to extract and presumably store unlock status/licensee, which is a hack vector if somebody wants to inject their own information.

Defox is extremely difficult to "crack" if you apply its highest protection with custom encryption of every line of code. I've only ever seen one credible extraction of material from an app protected by the most recent Defox and that involved deep knowledge of VFP's low level workings and brute force decryption = a huge effort that only a handful of people still can contemplate in 2017. Refox's latest version offers an alternative mechanism to thwart "hooking" cracks to which VFP otherwise is vulnerable. Whereas VFP Compiler doesn't care if you hook its VFP stub, since all the good stuff is in a C++ dll that you need to decompile or step through: again, only viable for an increasingly small pool of people such as Leonid himself, who is one of only 2 people to demonstrate a successful VFP compiler crack of a simple line of code.

FWIW, you can Defox or Refox a VFP Compiled app, but Refox and Defox can't add protection to each other.