KEY DISTRIBUTION SYSTEM OF CIPHER DEVICE

摘要

PURPOSE:To produce a common key by using the preparation end signal of a data terminal device of the called side as a trigger to perform an operation between the cipher devices of transmission and reception sides with an open key distribution system. CONSTITUTION:An MODEM5 of the called side receives a dial signal, and a call signal is turned on. Then a terminal preparation end signal ER is turned on for a terminal device DTE7. The ON of a DR signal transmitted from the MODEM5 is received after the ON of the signal ER is received from the device 7. Then a cipher device 6 of the called side starts an open key distribution system PKDS. The produced key information X is sent to the calling side from the called side. Then a positive answer signal and the produced key information Y are sent to the called side, and the called side performs transmission in the same way. Thus the produced keys are set at both sides.