This question was made by Francesco on Jul 29 '11 at 17:14. and the replies were not satisfactory due they not point to an important problem that´s: Why could anyone want to make certain data only accesible for a program but not to the users?.

For example: If I want to do a safe distribution of original music for demostration purposes I will need several requisites:

1) The music should be heard using a simple procedure like selecting the name of each song on a playlist of a mediaplayer.

2) The portable media, ussually a portable USB drive, must hide for complete and should make unaccesible the files that contain the audio data to anything but the mediaplayer, that must be in the first partition, the one that is visible.

3) Considering that´s impossible to really hide files in a non-hidden partition, a second hidden partition should be created in the USB drive and the audio data will be stored there.

4) The trick is to read the audio data files stored in the hidden partition with a mediaplayer stored in the visible partition, the media player also should be a complete standalone program and independent from any library of the operating system except of the OS audio system.

5) The hidden partition should have a copy protection scheme that could impede to do copies of the data or create working ISO images of it.

I know that this description could not be technically accurate but it has a complete logic from the needs of a music producer against the problem of piracy.

The philosophy that surrounds the concept is to transform a virtual object like a digital string of audio in a solid object like the analog vinyl discs are.