KEY MANAGEMENT SERVER, TERMINAL, COMMUNICATION SYSTEM, KEY DISTRIBUTION METHOD, KEY DISTRIBUTION PROGRAM, KEY RECEIVING METHOD AND KEY RECEIVING PROGRAM

摘要

PROBLEM TO BE SOLVED: To perform key distribution that achieves high-security communication between communication devices while suppressing processing loads applied to the communication devices. SOLUTION: A key management server 101 and each of communication devices 102 communicate using a device key. The communication devices 102 and 102 communicate with each other using a master key. The key management server 101 manages the master key and encrypts the master key using the device key and distributes the master key to the communication devices 102. Furthermore, the key management server 101 distributes to the communication devices 102 an instruction to update the device key at an arbitrary timing. After distributing the instruction, the key management server 101 updates the current device key in accordance with a predetermined unidirectional function and deletes the old device key. When each communication device 102 receives the instruction, the current device key is updated in accordance with the predetermined unidirectional function and the old device key is deleted. COPYRIGHT: (C)2010,JPO&INPIT