Spoof Blocker: is it possible?

I have a save code that saves part of the player name along with the code itself, but to be absolutely fool-proof I want to make sure that their name... is their name. I saw on FFOpenRPG that the "Colonel", or the big guy on the spire, says "someone tried to copy my code with a spoofer, how childish of them". So Im assuming there is a way (if he didn't throw in anything host-only to make sure it was him), and I want to find it out. Anyway does anbyody know a way?