| 摘要 |
PURPOSE:To prevent the reference of the content of a program on a storage device by leaving only the ciphered program on the storage device of a user system. CONSTITUTION:When a user 2 starts a program execution start means 4, it inputs the ciphered supply program 1, sets a ciphered program 6 in the storage device 5 and then it starts a program execution means 8. It inputs the ciphered program 6, sets it in an instruction decoding buffer 9, and then it starts a chiphered program decoding means 10. Then, it performs the program in accordance with a decoding result which is set in the instruction decoding buffer 9. The ciphered program decoding means 10 inputs the content which is set in the instruction decoding buffer 9, decodes the inputted content and sets the decoding result in the instruction decoding buffer 9. Thus, the program on the storage device 5 of the user system can be protected. |
