摘要 |
<p>In a network system for communication between a first terminal with an encrypting function and a second terminal without the encrypting function, a control data transmission device includes a receiving unit receiving control data sent from the first terminal to the second terminal, a data processing unit for extracting cipher information of the first terminal from the control data, a memory storing the cipher information of the first terminal, and a sending unit for sending the control data without the cipher information toward the second terminal, or sending to the first terminal the control data with the cipher information, and further sending the cipher information to the user data transmission device; a user data transmission device includes an encryption processing unit for decrypting the data that was sent from the first terminal to the second terminal while encrypting the data as sent from the second terminal to the first terminal.</p> |