| 摘要 |
PURPOSE: To attain communication with a ciphering key corresponding to sets of a terminal address and a data class in the data transmission reception between terminal equipments by using a terminal address of a communication opposite party and a registered ciphering key so as to apply ciphering processing to data included in the communication information. CONSTITUTION: A ciphering information table 2 provided corresponding to a ciphering device 3 stores an IP(Internet Protocol) address of a communication opposite party, a data class and a ciphering key with cross reference. Then the ciphering device 3 decodes a TCP(Transmission Control Protocol) data part of an IP packet with the ciphering key registered in the ciphering information table 2 based on sets of the IP address and the data class when sets matching with those of the transmitter IP address and the data class in the received IP packet are in existence in the ciphering information table 2 and gives the IP packet to the terminal equipment. When the same sets are not in existence in the table 2, the device 3 does not conduct decoding and gives the IP packet to the terminal equipment. |
