摘要 |
In encryption transmission employing a conventional optical transmission apparatus, since a dedicated hardware unit to be used executes a complicated signal process, there are the problems that a high-speed transmission speed is difficult to realize and an entirety of a transmission system employing encryption becomes high in cost. An optical signal transmitter for encryption and an optical signal receiver for encryption, employing optical multi-value transmission which is high in cost and in which an effective improvement of transmission speed is difficult, are used only for exchanging an encryption key and data to be actually transmitted is transmitted by another line. A data signal is transmitted by using: the exchanged encryption key after communication of the encryption key is executed by using the transmitter and receiver for encryption transmission prior to the data transmission; and another system of high-speed signal transmission line in an encryption transmission circuit. |