And how would you enforce that? What would prevent anyone with access to the code from building it and using it? I don't see any way except maybe stripping the code of significant parts
The fingerprints have to be some sorts of data, like regular expressions or other limited instruction set which can only parse the incoming file and not communicate with outside world.
The company could automatically release fingerprints into the open after a time, say 6 months.
This seems like a pretty good business model idea though!