There is disclosed a digital information system which has a digital contents protection function using WM information. The system uses the WM information during a first ripping processing to execute a first verification processing for verifying validity regarding use of contents. In this case, ID information of music contents as a ripping object is registered. The system uses the ID information to execute a second verification processing for verifying the validity regarding the use of the contents without executing the first verification processing using the WM information during the ripping processing of the music contents corresponding to the registered ID information.