| 摘要 |
PURPOSE:To mask the content of a program even when a memory device is referred during the execution of the program by converting the instruction of an enciphering program to a form feasible with a program execution means by an enciphering program decoding means. CONSTITUTION:When a user starts up a program execution start means 4, the program execution start means 4, after setting an enciphering supply program 1 as the enciphering program 6, starts up the program execution means 12. The program execution means 12 takes out the instruction from the enciphering program 6 set on the memory device 5, and after setting it on an instruction decoding buffer 13, starts up the enciphering program decoding means 14. The enciphering program decoding means 14 decodes the instruction set at the instruction decoding buffer 13, and converts it to the form feasible with the program execution means 12, and sets it on the instruction decoding buffer 13. In such a way, it is possible to mask the contents of the program 1 and data 7. |
