There is no way to really "lock" files. We could do comparisons/hash checks but in reality they are easy to bypass. Something as simply as changing the color of the hair would throw the entire thing off.

It's a lot like games implementing DRM. They put a lot of time, effort and money into preventing people from pirating it... and it's still going to get pirated. All it does is screw over the legit users and at best, slow down the pirates slightly.