BACKUP SYSTEM, PROGRAM, BACKUP SERVER AND BACKUP METHOD

PROBLEM TO BE SOLVED: To easily back up data without leaking information to a third party. SOLUTION: A client device acquires an attribute certificate set with a file name from an attribute certificate server in each backup target file, and attaches the attribute certificate to the file, and transmits it to a file server. The file server stores the file, and registers the attribute certificate in a repository. When the client device 2 receives input of a storage date of the file of a restoration target from a user, the client device 2 acquires the file name set to the attribute certificate generated on the date, and displays a list of the file names on the screen. When the user designates the file of the restoration target from the list, the client device 2 acquires the file from the file server. COPYRIGHT: (C)2007,JPO&INPIT