| 摘要 |
PROBLEM TO BE SOLVED: To prevent data from being easily stolen by a wrong user and to construct a document data base, where many publications are digitized, without infringing on the rights of authors. SOLUTION: An cipher unit 20 is freely detachably attached to a computer main body 10 where a document data base 31 is stored, and the computer main body 10 is provided with a user file 32, where plural correct user names are recorded, and a user check program 22 which checks whether an inputted user name coincides with one of correct user names recorded in the user file 32, and the cipher unit 20 is provided with a data base code 21 corresponding to the document data base 31 and a code check program 22 which checks whether the data base code 21 coincides with the document data base 31. |
