Patent ID: 8923518
Filing Date: 2014-12-30
Classification: H04L,H04W

Abstract:
1. A key distribution system comprising: a plurality of wireless communication terminal devices that includes a first wireless communication terminal device and a second wireless communication terminal device constructing an ad-hoc network; and a server that distributes, to the plurality of wireless communication terminal devices, a key for encrypting information transmitted by the plurality of wireless communication terminal devices with each other over the ad-hoc network, the first wireless communication terminal device comprising an attribute value transmitter that transmits an attribute value of the second wireless communication terminal device to the server, and the server comprising: a key managing information storage that stores attribute values of the plurality of wireless communication terminal devices and a plurality of keys in association with each other; and a key distributer which obtains, from the key managing information storage, a plurality of keys corresponding to an attribute value transmitted by the attribute value transmitter, obtains a predetermined number of keys maximizing a posterior probability of, among the plurality of obtained keys, the keys being stored in a plurality of wireless communication terminal devices having a same attribute value as the attribute value transmitted by the attribute value transmitter and having a communication repetition larger than a predetermined value among the plurality of wireless communication terminal devices, and transmits the predetermined number of obtained keys to the first wireless communication terminal device; wherein the key distributor further: