| 摘要 |
PURPOSE: To perform security protection in the case of detaching a storage device storing confidential data and reading them in a different device. CONSTITUTION: When a control part 3 and the storage device 3 storing the confidential data 8 are connected through a bus line 2, when the storage device 3 is cut off from the bus line 2, the backup of the storage device 4 storing a decoding key 9 is automatically detached and the decoding key 9 is invalidated. A person to utilize the confidential data 8 stored in the storage device 3 recognizes that the decoding key 9 is required for the first time when the storage device 3 is mounted to the different device. The decoding key is not stored in the storage device 3. Also, at the time, even when the storage device 4 storing the decoding key 9 is checked, the decoding key 9 can not be utilized any more. |
