| 摘要 |
PURPOSE:To protect the secrecy of software by preventing the embezzlement of a program by providing a code conversion means at the preceding stage of an instruction register, and setting an instruction code differently at every user. CONSTITUTION:The code conversion means 11 is provided just before the instruction register 13, and also, such configuration is provided that it is controlled whether or not conversion by the code conversion means 11 should be performed by a signal, and the validity/invalidity of the code conversion means 11 or a code conversion system itself is dynamically varied corresponding to the progression of the program. Therefore, no instruction is executed correctly until matching with the code conversion system by hardware or firmware in a microprocessor is taken even when only the imitation of a program or the switching of a ROM is performed. In such a way, it is possible to protect the secrecy of the software by preventing the embezzlement of the program. |
