PuzzlePalace's design is forward thinking and in tune with OS X like no other application or utility I've seen for OS X so far. Think of it as a drag-n-drop "service" and you've got the right idea. I'd like to see the author take this a step further in the next version allowing content, not just files, to be dragged into (and the encrypted result out of) PuzzlePalace, as well as a companion cocoa menu service to provide encryption/decryption directly in documents. This would be most useful with public-key type enryption, such as PGP. No doubt this capability is dependent upon Apple taking their OS X service (and thus document) concept to the next step.