Communication apparatus, reception control method, and transmission control method

A communication apparatus comprising:

• a transmission and reception part receiving a packet from a network and producing a receive data which includes a header section and a data body on the basis of the received packet in a reception operation, and making a packet on the basis of a transmit data which includes a header section and a data body and transmitting the packet to the network in a transmission operation;
• a security part encrypting the data body including at least plain-text data in the transmit data;
• a control part connecting the transmission and reception part to the security part through a system bus;
• an encryption data processing part connected to the system bus;
• and
• a second bus connecting the encryption data processing part to the security part, and being different from said system bus,
• wherein the control part produces the transmit data and supplies an encryption command for the plain-text data to the security part through the system bus together with the transmit data in the transmission operation,
• the security part encrypts the plain-text data of the data body in the transmit data supplied from the control part according to the encryption command to make encrypted data, supplies the transmit data including the data body including the encrypted data to the encryption data processing part through said second bus after encrypting the plain-text data, and supplies the transmit data to the control part through the system bus in response to the encryption command,
• the control part supplies the transmit data while reducing in volume said data body of the transmit data in response to the encryption command to the encryption data processing part through the system bus together with a transmit command, and
• the encryption data processing part supplies the transmit data including the data body having the reduced data volume, which are received from the control part, and the transmit data, which are received from the security part through said second bus according to the transmit command, to the transmission and reception part for packet transmission.

A reception control method of a communication apparatus including a transmission and reception part receiving a packet from a network and producing a receive data which includes a header section and a data body on the basis of the received packet during a reception operation, and making a packet on the basis of a transmit data which includes a header section and a data body and transmitting the packet to the network during a transmission operation, a security part decrypting the data body including at least encrypted data in the receive data, a control part connected to the transmission and reception part and the security part through a system bus, an encryption data processing part connected to the system bus, and a second bus connecting the encryption data processing part to the security part and being different and separated from said system bus, the reception control method comprising:

• a receive data supplying step of supplying the receive data from the encryption data processing part to the security part through said second bus when the data body of the receive data produced in the transmission and reception part includes encrypted data, and supplying the receive data from the encryption data processing part to the control part through the system bus during the reception operation;
• a decryption command issuing step of supplying a decryption command from the control part to the security part through the system bus together with the receive data while reducing in volume said data body of the receive data when a determination is made that the receive data received to the control part include the encrypted data;
• and
• a decryption step decrypting the encrypted data of the data body included in the receive data, which are supplied from the encryption data processing part to the security part through said second bus, according to the decryption command to make plain-text data, and supplying plain-text data from the security part to the control part through the system bus in response to an encryption command.