| 摘要 |
PURPOSE: To provide a system which enables ciphering and deciphering to be carried out with efficiency without a program being falsified. CONSTITUTION: Enciphered enciphering/deciphering processing programs Pr1, Pr2,... are transmitted from an information processing device to an IC card by an initial program IP when a password agrees, the IC card deciphers these programs with a deciphering key of a rightful user and sends them back. An information processing device disposes these programs in a work memory area PA, causes them to get started and carried out data enciphering/deciphering processing. Accordingly, these programs, being normally in an enciphered condition, are neither analized nor falsified by a third party. After the rightful user has completed data processing, the deciphered plain programs are erased so as not to leave room for the plain programs surviving after the processing, and security of these programs is thereby assured. Enciphering work can be carried out with efficiency without a need for work of taking a storage medium of these programs out of a deposit place and setting it in the information processing device. |
