| 摘要 |
PURPOSE:To improve the intensity of enciphering by providing a function controlling a control signal to a terminal device and an MODEM and a function enciphering all information inputted from a terminal device in a data communication cipher device enciphering the communication between terminal devices. CONSTITUTION:A cipher device at transmission side 2 detects an RS signal from a central processing unit 1 by an RS/CD control section 9 and transmits an open key of the transmission side cipher device 2 from an enciphering and decoding circuit 11 to a receiving side cipher device 6. The reception-side cipher device 6 detects a CD signal ON by the RS/CD control section 9 to transmit the open key of the receiving side cipher device 6 to the transmission-side cipher device 2 and to set a key for enciphering/decoding between the transmission side cipher device 2 and the reception side cipher device 6 to an own enciphering/decoding circuit 11, and the transmission-side cipher device 2 returns the CS signal ON from an interface control section 8 to the central processing unit 1 at the receiving of the open key from the reception-side cipher device 6. Then, the information transmitted from the central processing unit 1 is enciphered and transmitted to a data terminal device 7. |
