| 摘要 |
PURPOSE:To improve the security of data stored in an external storage medium of a terminal equipment in the case of operating the terminal equipment by using an IC card by using confirming information to which the IC card is inputted, as key information for encipherment, and combining it with the selection of algorithm. CONSTITUTION:When confirming information to which an IC card is inputted is used as key information for encipherment, it is unnecessary to provide specially the key information, and also, by combining it with the selection of algorithm, the encipherment of two stages can be executed, therefore, the encipherment of data stored in an external storage medium 11 which can be attached and detached to and from a terminal equipment 1 can be made more complicated. Also, the confirming information which becomes the key information for encipherment and the information for selecting the algorithm for encipherment do not exist in the terminal equipment 1 but are held in the inside of the IC card 10 for managing use authority information. Accordingly, it is difficult to obtain them directly, and unless the use authority exists, the algorithm related to encipherment cannot be selected, and its key information cannot be obtained either by the terminal equipment 1. In such a way, the security of the whole system can be improved. |
