Abstract: In a network registration system including a communicator to be registered on a network and a register registering the communicator on the network, either of the communicator and the register includes a check information generator generating a check information signal according to check information for prompting the user to check that the communicator is treated as an object to be registered in the network registration system; and a check information output section outputting the check information signal in a form sensible to the user. The other of the communicator and the register includes an evaluation criterion supplier supplying evaluation criterion information allowing the user to evaluate the suitability of the check information emitted from the check information output section. Thus, the network registration system can prevent an incorrect registration while easily registering the communicator to the network.

Abstract: First communication units use a public key thereof certified by a certification authority on a PKI (Public Key Infrastructure), which is held by the first communication units in advance, and a secret key of the first communication units or delegation information generated by using secret information, as public key certificate, of the first communication units to thereby allow a proxy server to perform security processing, i.e. key exchange processing, authentication processing or processing for providing compatibility of encryption schemes, between the first communication units and a second communication unit on behalf of the first communication units.

Abstract: In a communicator in a communication system, a commission information generator for generating a commission parameter to make a process on a communication between communicators performed by another computer includes a first memory for storing a secret key and an encrypter for generating N number of the commission parameters, where N is a natural number, from a first to an N-th commission parameter. The encrypter regards a j-th shared key, where j is a positive integer equal to or less than N, out of the N number of shared keys as key information, encrypts a bit sequence representation of j-th partial information, associated with the j-th shared key, out of N pieces of partial information, and thereby generates a j-th commissioned parameter.

Abstract: A communication terminal generates a temporary network key based on a managed master network key and on key identification used for security processing on a communication frame. The security processing is performed on the communication frame using the temporary network key. A secure communication frame is produced in which the identification of the key is indicated.

Abstract: In a network registration system including a communicator to be registered on a network and a register registering the communicator on the network, either of the communicator and the register includes a check information generator generating a check information signal according to check information for prompting the user to check that the communicator is treated as an object to be registered in the network registration system; and a check information output section outputting the check information signal in a form sensible to the user. The other of the communicator and the register includes an evaluation criterion supplier supplying evaluation criterion information allowing the user to evaluate the suitability of the check information emitted from the check information output section. Thus, the network registration system can prevent an incorrect registration while easily registering the communicator to the network.

Abstract: There is provided a secure communication system comprising first and second communication apparatuses carrying out encrypted communication. The first communication apparatus includes: a first established communication path managing unit managing information on an encrypted communication path established with the second communication apparatus; and a first communication path reestablishing unit notifying the second communication apparatus of first communication apparatus identification information and operating with the second communication apparatus to reestablish an encrypted communication path using the information on the established encrypted communication path.

Abstract: A communication device receives secure communication frames on which a security transform has been performed to permit authentication. The communication device maintains an authentication history and a local time varying parameter. In multi-hop communication, the communication device provisionally verifies the freshness of a received secure communication frame by verifying that identifying information extracted from the frame is not already present in the authentication history and that a received time varying parameter extracted from the frame is not older than the local time varying parameter by more than a certain margin. If these freshness tests both pass, the frame is authenticated. If authentication succeeds, the frame is transmitted on the next hop without performance of a new security transform.

Abstract: A receiving device sends challenge information to a transmitting device. The transmitting device initializes a time varying parameter and transmits communication data together with data derived from the challenge information to the receiving device. Subsequent communication data, if any, are then transmitted together with data derived from the time varying parameter. The receiving device uses the challenge information to verify the freshness of the communication data transmitted first, and uses the time varying parameter to verify the freshness of the subsequent communication data. Freshness can be verified without having to maintain any type of verification data during sleep periods, and without having to send a separate challenge for each data transmission.

Abstract: A transmission terminal includes an information generation unit, a transmission unit, a delivery management unit, and a reception unit. The information generation unit generates information that is to be transmitted to a destination reception terminal. The transmission unit transmits information that the information generation unit has generated. The delivery management unit manages transmission of information. The reception unit receives information that the destination reception terminal transmits. Furthermore, the information generation unit generates or receives transmission information that is to be transmitted to the destination reception terminal and generates redundant information for the destination reception terminal to restore the transmission information.

Abstract: A wireless transmitter device has a predetermined upper limit of an accumulated data transmission time per predetermined duration corresponding to a predetermined maximum value. The wireless transmitter device includes a timer which starts keeping time when the wireless transmitter device sends a wireless signal and stops when it reaches a timeout value, a total transmission measurer for measuring the data transmission time of the wireless transmitter device during a period from the timer starting to stopping, and a transmission controller for refraining the data transmission at the earliest until the time being measured by the timer reaches the timeout value if the accumulation time is, or likely to be, equal to or larger than a threshold value.

Abstract: A communication terminal generates a temporary network key based on a managed master network key and on key identification used for security processing on a communication frame. The security processing is performed on the communication frame using the temporary network key. A secure communication frame is produced in which the identification of the key is indicated.

Abstract: A communication device receives secure communication frames on which a security transform has been performed to permit authentication. The communication device maintains an authentication history and a local time varying parameter. In multi-hop communication, the communication device provisionally verifies the freshness of a received secure communication frame by verifying that identifying information extracted from the frame is not already present in the authentication history and that a received time varying parameter extracted from the frame is not older than the local time varying parameter by more than a certain margin. If these freshness tests both pass, the frame is authenticated. If authentication succeeds, the frame is transmitted on the next hop without performance of a new security transform.

Abstract: A position estimating system capable of accurately estimating the position assumed by a target terminal user based upon measurement of wireless reception signal levels of signals from a target terminal is provided. The position estimating system includes a target terminal that wirelessly transmits a position estimation request, a plurality of reference terminals disposed at specific positions which, measure the signal strength of wireless signals from the target terminal and a position estimating server that estimates the position of the target terminal based upon the reception signal levels measured in correspondence to each of the reference terminals. The reference terminals each include a reception signal level utilization OK/NG judgment unit that makes a judgment as to whether or not the reception signal level value having been measured is to be used in position estimation based upon an index indicating the level of reliability of the reception signal.

Abstract: A receiving device sends challenge information to a transmitting device. The transmitting device initializes a time varying parameter and transmits communication data together with data derived from the challenge information to the receiving device. Subsequent communication data, if any, are then transmitted together with data derived from the time varying parameter. The receiving device uses the challenge information to verify the freshness of the communication data transmitted first, and uses the time varying parameter to verify the freshness of the subsequent communication data. Freshness can be verified without having to maintain any type of verification data during sleep periods, and without having to send a separate challenge for each data transmission.

Abstract: A wireless multi-hop network of a communication system is structured with a number of the communication devices and the collecting communication device. Transmission information from each communication devices is sequentially relayed to reach the collecting communication device. Each communication device features a function for on/off control of a transmission/reception processing section.

Abstract: A transmission terminal includes an information generation unit, a transmission unit, a delivery management unit, and a reception unit. The information generation unit generates information that is to be transmitted to a destination reception terminal. The transmission unit transmits information that the information generation unit has generated. The delivery management unit manages transmission of information. The reception unit receives information that the destination reception terminal transmits. Furthermore, the information generation unit generates or receives transmission information that is to be transmitted to the destination reception terminal and generates redundant information for the destination reception terminal to restore the transmission information.

Abstract: A wireless transmitter device has a predetermined upper limit of an accumulated data transmission time per predetermined duration corresponding to a predetermined maximum value. The wireless transmitter device includes a timer which starts keeping time when the wireless transmitter device sends a wireless signal and stops when it reaches a timeout value, a total transmission measurer for measuring the data transmission time of the wireless transmitter device during a period from the timer starting to stopping, and a transmission controller for refraining the data transmission at the earliest until the time being measured by the timer reaches the timeout value if the accumulation time is, or likely to be, equal to or larger than a threshold value.

Abstract: The present invention provides a communication terminal which can make connection to a communication terminal the position of which can be specified in an actual space but the ID information of which is not known through a network.

Abstract: An object of this invention is to avoid interfering from a radio LAN transmission unit and being interfered. This invention relates a radio transmission unit for transmitting according to a second radio transmission system which transmits/receives data signal under the same frequency band as first radio transmission system in which prior to transmitting of the data signal, a transmitting station transmits a transmission request signal while a reception station receiving this RTS sends back a reception preparation completion signal. This radio transmission unit comprises CTS transmitting means for transmitting CTS according to the first radio transmission system and a duration setting circuit for setting a duration time to be overlaid on the CTS, and prior to transmitting according to the second radio transmission system, the duration time set by the duration setting circuit is overlaid on the reception preparation completion signal according to the first radio transmission system.

Abstract: A wireless multi-hop network of a communication system is structured with a number of the communication devices and the collecting communication device. Transmission information from each communication devices is sequentially relayed to reach the collecting communication device. Each communication device features a function for on/off control of a transmission/reception processing section.