| 摘要 |
PROBLEM TO BE SOLVED: To provide an encryption key management method by which key is switched so as not to be obtained by a third party in the case of switching the key by communication between a server and a terminal. SOLUTION: The encryption key management method is provided with a key selection step in which the server 1 selects keys different from the one presently used among a bundle of keys in a prescribed order, a key switching step in which the server 1 switches a key on the side of the server 1 to a selected key, an encryption step in which the server 1 encrypts information about switching the keys, an information step in which the server 1 informs the terminal 9 of encrypted information that the keys are switched in the case of switching a key to be commonly used by the server 1 and the terminal 9, second key selection step in which the terminal 9 selects the same key as the key on the side of the server 1 after switching among the bundle of keys according to the same order as in the server 1 and a key selection step in which the terminal 9 switches a key on the side of the terminal 9 to the selected key in the case that the server 1 gives information to the terminal 9. COPYRIGHT: (C)2004,JPO
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