| 摘要 |
PURPOSE:To have a function to hold a secrecy for the information kept by itself by incorporating an information converting means to code or decode the information and the control information to exchange the information. CONSTITUTION:A single chip microcomputer includes a CPU 2, a RAM 3, a ROM 4, an EEPROM 5, an input output circuit 6 and other peripheral circuit 7. The interface between the input output circuit 6 and an external part is executed through an enciphering device 9 which enciphers selectively the data to be outputted to the external part and supplies them to the external part, and a decoder 10 which decodes selectively the data supplied from the external part and gives them to an internal part. The enciphering and decoding algorithm in the enciphering device 9 and the decoder 10 is determined in accordance with the prescribed key word composed of plural bits. |
