Abstract: A relay apparatus comprises a frame relay processing unit for relaying a frame, a plurality of ports for sending and receiving the frame to and from the outside, and a cryptographic processing module corresponding to each of the ports. Each cryptographic processing module is connected to the corresponding port and to the frame relay processing unit by means of general-purpose interfaces such as MII. The cryptographic processing module performs the encryption process and decryption process so that the frame relay processing unit can concentrate on the relay process and the relay speed is not subject to degradation. Also, the cryptographic processing module can generate a different cryptographic key for each frame without requiring dynamic exchange of key information.

Abstract: Asymmetric key generation apparatus generates asymmetric key based on a different key material for each piece of data. The symmetric key generation apparatus is configured to generate a symmetric key of a practically different value for a key material of a different value. An encrypted piece of data has a part encrypted by a symmetric key and a part of a cleartext. The latter part includes a key material used by the symmetric key generation apparatus that uses it for generating a symmetric key.

Abstract: A relay apparatus comprises a frame relay processing unit for relaying a frame, a plurality of ports for sending and receiving the frame to and from the outside, and a cryptographic processing module corresponding to each of the ports. Each cryptographic processing module is connected to the corresponding port and to the frame relay processing unit by means of general-purpose interfaces such as MII. The cryptographic processing module performs the encryption process and decryption process so that the frame relay processing unit can concentrate on the relay process and the relay speed is not subject to degradation. Also, the cryptographic processing module can generate a different cryptographic key for each frame without requiring dynamic exchange of key information.

Abstract: A packet relay apparatus is disposed that relays packets between an inside node and an outside IP network. A class processing unit classifies send packets to be relayed to the IP network and allocates different virtual IP addresses thereto. A send packet relay unit translates source addresses of the send packets to be relayed to the IP network into virtual IP addresses on a class by class basis, to establish classified IP communication paths. For reply packets from the IP network passing through communication paths on a class by class basis, a reply packet relay unit inversely translates destination virtual IP addresses into original addresses by reference to the results of address translation effected by the send packet relay unit.

Abstract: An entry processing unit enters into a table the frame information and the reception time of a frame received by a frame reception unit. Upon the receipt of a frame by the frame reception unit, a loop judgment unit refers to the table to detect a second reception of the same frame to thereby judge the occurrence of a loop. Based on this judgment, the frame processing unit discards the received frame without sending the same, to obviate the occurrence of an infinite loop.