Simulate USB device with arduino and raspberry pi

Hi,

I have a device which is a black box, this black box is interfaced with a USB key.

This USB key has 2 purposes. First it contains a file with some text in it defining the configuration of the black box. Secondly it is used to register some information gathered over time by this black box on another usb key's file.

For a project i need to centralize the information of many black box. So i was wondering if it is possible to simulate a kind of usb harddisk with an arduino and a raspberry pi.

I have already searched on the net and find that it would probably need to write drivers to make this type of thing.

Do you have any idea which could simplify my life and easily interfaced this black box with a rasberry pi? I would need to add a usb output could you redirect me to some documentation helping me in this purpose?

Thanks in advance,

Antoine