| 摘要 |
PROBLEM TO BE SOLVED: To prevent data in an external storage device from being properly read out except for a main body device where data ware written. SOLUTION: An encipherer/decipherer 12 is arranged on a data transfer path between an external storage device control part 11 and an external storage device 16. The encipherer/decipherer 12 enciphers/deciphers data with data in a device number storage memory 13 for storing a device number peculiar for the main body device as a key, and data on the external storage device 16 can not be deciphered except for the main body device having the same device number. Besides, since it is not necessary to encipher a command for controlling the external storage device 16, the control command has a path (a) so as to be directly dispatched to the external storage device 16 without through the encipherer. |
