USB Drive that can discoect itself

This is just an idea I'm trying to do, but I don't know where to start. Imagine having a USB Drive that you can coect it to selected PCs. If the USB drive ever get coected to any other device or PC, it will discoect. I don't want to use encryption because what if I wanted to do this to a MP3 player. so my only idea that comes to my mind is the auto run file that runes once the USB is coected and look for a file on the coected PC or device, if doesn't find it then it discoect, if it does then it stay coected.

does anyone have any idea where to start with this idea.