Alright so UE4 is a game ENGINE. It's not an actual game. Without further information you won't receive any help here as it's very unclear what you're asking. Engines like UE4 support different file types for resource files, if that's what you're trying to make a tool for. With an engine like UE4 you can have custom file / data wrappers all around, maybe with some resource encryption, we don't know what your topic is about.
If you're looking for some help at least take the effort to describe your topic properly please.