| 摘要 |
PURPOSE: To safely erase a specific file by using an encryption algorithm to prevent file contents from being retrieved by other users after erasing them. CONSTITUTION: A file 20 stored in a permanent storage medium 15 of a computer system 16 which prevents the file from being accessed by unauthorized persons is processed as follows; the stored file 20 is selected, and an erase command 11 is inputted, and a random key 21 is used to cipher the stored file 20, and the file 20 is operated by an encryption algorithm 13 to erase a file dictionary pointer 23 to the file 20 (14). At the time of reproducing the file, a method 10 reproduces the file dictionary point 23 to the file 20, and the random key 21 is used to decode the ciphered stored file 20 for the purpose of permitting the access to data included in the stored file 20. |
