| 摘要 |
PROBLEM TO BE SOLVED: To shorten authentication time, when carrying out authentication, using two or more encryption keys. SOLUTION: A data D024 from a memory 11 and a degenerate key from an encryption key K1 are generated and transmitted to an IC card 3, together with information on sequence of degeneration (Here, Provider 2, Provider 4, Provider's 1, in this order). In the IC card 3, a degeneration processing portions 32 is controlled, corresponding to these items of information, the degenerate key is formed, and data D0 is read from a memory 31. It sequentially degenerates, using an encryption key of a specified sequence and a specified provider's number.Namely, the data D0 is degenerated using an encryption key K2, and data D02 is derived. This data D02 is degenerated using an encryption key K4, and data D024 is derived. Further, an encryption key K1 is used for this data D024, and the degenerate key is generated. Thus, the degenerate key generated is the same degenerate key as the degenerate key which a degeneration processing portion 13 of a controller 1 has formed. COPYRIGHT: (C)2005,JPO&NCIPI
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