Abstract:
A communication system, including: a NW management device which (i) forms a network together with an authenticated target device, and (ii) manages the network by delivering a session key for use in communication in the network to the authenticated target device; and a device authenticated by the NW management device, wherein the NW management device: determines whether or not to permit the device to be an alternative management device which manages the network in replace of the NW management device when communication is impossible in the network; shares, with the device, authentication information about the authenticated target device, when permitting the device to be the alternative management device; and the device shares the authentication information with the NW management device, and starts managing the network using the authentication information as the alternative management device when determining that the NW management device cannot communicate in the network.
Abstract:
A first device, upon detecting participation in an authentication system, transmits new and old identification information of a first certificate revocation list that the first device manages to a second device. In a case where the new and old identification information of a second certificate revocation list that the second device manages is older than the new and old identification information of the received first certificate revocation list, the second device transmits a transmission request for the first certificate revocation list to the first device. Upon receiving the transmission request for the first certificate revocation list from the second device, the first device transmits the first certificate revocation list to the second device. the second device updates the second certificate revocation list using the received first certificate revocation list.
Abstract:
At least one controller in a group selects a coordinator that manages a group key to be used in common in the group from among controllers in the group in accordance with an attribute of the controllers. The selected coordinator generates a group key, performs mutual authentication with devices and the controllers in the group, and shares the generated group key with devices and controllers that have been successfully authenticated. The coordinator then generates encrypted data and authentication data by using the group key and simultaneously broadcasts a message including the encrypted data and the authentication data.
Abstract:
An information providing apparatus includes: an inputter that obtains log information and personal information corresponding thereto; a tentative ID giver that gives each tentative ID to the personal information at each predetermined timing; a first storage that stores correspondence-relationship information indicating a correspondence relationship between the personal information and the each tentative ID; a receiver that receives a request for outputting information including a requested tentative ID identified by a current tentative ID given and the one past timing when the requested ID was given; an information processor that determines, in accordance with the request, link-relationship information indicating a correspondence relationship between the requested tentative ID and the current tentative ID; a second storage that stores the determined link-relationship information; and an outputter that outputs first information including the requested tentative ID or second information indicating that first-information outputting is not permitted, based on the stored link-relationship information.