| 摘要 |
PURPOSE: To eliminate the need for a fixed master key and to improve secrecy and productivity by generating key values of prescribed functions corresponding to control signals for opposing communication equipment. CONSTITUTION: A communication equipment 1 generates a code signal 4 for a function both of a command signal 3 and of a key value 6 and a communication equipment 2 generates a code signal 5 for a function both of the signal 3 and of a key value 7 and both the code signals 4, 5 are mutually compared by a CMPR 10. When both the signals 4, 5 are equal, communication is started, and after the communication, 1st and 2nd succeeding control signals 8, 9 are generated. In this case, key values 6, 7 are generated as a function of the key values 6, 7 at the same time as the control signals 8, 9. Only when the code signals 4, 5 and the key values 6, 7 are respectively identical and the control signals 8, 9 are the same, the system accurately functions. These values can be unintentionally generated and a fixed master key is not required. |
