Nec Corporation

Nara Institute of Science and Technology

Nec Engineering, Ltd.

Agc Inc.

Jun Noda

Hiroyuki Seki

Tohru Kimura

Yoshitaka Nakamura

Hitoshi Yano

Isamu Teranishi

Kazue Sako

Koji Fukami

Nobuhide Yoshida

Yuuichi Aoki

Akitake Mitsuhashi

Daigo Taguchi

Teruki Sukenari

Yuichi Nino

Hiroyuki Hayakawa

Takeshi Murofushi

Kunihiro Suzuki

A sensor network includes a sensor management server which is mutually connected with many sensor terminals. The sensor management server includes: a key delivery module for transmitting a key update message to the respective sensor terminals; a communication volume detection module for detecting a communication volume used for transmitting the key update message; and a multiplicity determination module for specifying a numerical value as a multiplicity, which represents the lower limit number of key update messages transmitted to the respective sensor terminals, according to the detected communication volume. The multiplicity determination module specifies the multiplicity such that the communication volume for transmitting or retransmitting the key update message takes the minimum value, and the key delivery module transmits the key update message by using the minimum communication volume that corresponds to the specified multiplicity.

Sensor network, sensor management server, key updating method and key updating program

According to a method of generating a key of the present invention, a first device and a second device are first brought into contact with one vibrator. In this state, the vibrator generates vibration. A first acceleration sensor provided in the first device and a second acceleration sensor provided in the second device detect the vibration. Subsequently, the first device notifies the second device of a first feature value based upon the detection result of the first acceleration sensor. The second device notifies the first device of a second feature value based upon the detection result of the second acceleration sensor. Then the first device compares the notified second feature value with the first feature value and generates a key based upon the comparison result. The second device compares the notified first feature value with the second feature value and generates a key based upon the comparison result.

Method of generating key

In order to reduce the frequency with which communication occurs when updating a network key is reduced and minimize the deterioration in performance due to updating without relying on a key tree, a server is provided with an address key allocation unit which generates identifiers for identifying clients by the combination of addresses on a plurality of address spaces and allocates address keys to respective addresses included in the generated identifier, and a network key ciphering unit which generates a network key update key which cannot be generated from the address keys allocated to a client to be disconnected, ciphers a new network key using the network key update key, and delivers the new network key to the clients.

Network key update system, a server, a network key update method and a recording medium

A key distribution system includes a server and terminal devices constructing an ad-hoc network and communicating with each other with information being encrypted by a key distributed from the server. The server obtains a predetermined attribute value desired as a communication counterparty by the terminal device from the terminal device, and obtains a plurality of keys corresponding to the obtained attribute values from a key managing information. The server obtains, among the plurality of obtained keys, m number of keys that maximize the posterior probability that the keys are stored in the terminal device having the same attribute value as the attribute value obtained from the terminal device and having the number of communications larger than a predetermined value, and transmits the m number of keys to the terminal device.

Key distribution system, key distribution method, and recording medium

In order to complete an authentication process in shorter time in a case where there is a large number of clients which concurrently authenticate a server, the server in a server authentication system includes an address key allocation means for generating an identifier to identify each of the clients by a combination of addresses on a plurality of address spaces and allocating address keys to the respective addresses configuring the generated identifier, and a message authentication code generation means for generating message authentication codes corresponding to a message by using the address keys allocated by the address key allocation means. Each of the clients includes a server authentication means for authenticating the server based on the message authentication codes generated by the message authentication code generation means.

Server authentication system, server authentication method, and program for server authentication

There is provided a wireless communication terminal that autonomously determines whether the wireless communication terminal is in a state in which flooding should be performed or a state in which the flooding should not be performed in a wireless ad-hoc network. At each predetermined time, the wireless communication terminal that performs the flooding autonomously infers whether the wireless communication terminal is in a state in which the flooding should be performed or a state in which the flooding should not be performed from the number of flooding packets that are of a packet flooded from surrounding wireless communication terminals based on a hidden Markov model.

Wireless communication terminal, wireless communication forwarding control system, wireless communication forwarding control method, and wireless communication forwarding control program

A communication network of the present invention includes: a plurality of superordinate nodestoforming a cascade type topology; and a plurality of terminal nodesto, connected to at least one superordinate node from among said plurality of superordinate nodes and forming a star type topology with the superordinate node connected.

Communication network, information processor and address assigning method

To provide an architecture information processing system having a small circuit size capable of reducing power consumption and cost, on which system a circuit simultaneously executing encryption processing and message authentication (falsification detection processing) can be mounted. An information processing system includes at least: a parameter storage section that retains an initialization vector used as a starting block of concatenation and an encryption key used for encryption; a one-way hash calculation section that executes a one-way hash calculation as a technique for realizing message authentication and functioning in place of the conventional common key block encryption (DES encryption) operation as an encryption operation section of a block encryption mode use section performing encryption processing and/or decryption processing as a CFB mode and/or an OFB mode; and a key overlay operation section that performs calculation for overlaying an encryption key retained in the parameter storage unit on data input to the encryption operation section.

Growing community of inventors

Tokyo, Japan

Jun Noda