| 摘要 |
PROBLEM TO BE SOLVED: To provide a key management method capable of generating and distributing mutually different decoding keys (private keys) to a plurality of users of a certain specific group when electronic information is used or shared by the plurality of users of the specific group, and to provide an encryption processing function such as a secure encrption, a decryption, the generation of electronic signature data and vea rification by physically stopping the use of the private keys when the private keys possessed by the users falls on unexpected situations such as loss, theft. SOLUTION: An encryption system of public keys, the private keys of an elliptic curve is utilized, mutually different decryption keys (private keys) having decryption functions equivalent to those of the private keys are generated, only relation between a discrete logarithm problem and an indefinite equation of the elliptic curve is established between the private keys and the decryption keys (private keys) to be generated and computation of the private keys is prevented. The public keys are generated by a plurality of two or more private keys, the plurality of private keys are physically stored in other places, the private keys are interlocked to execute encryption processing such as decryption and creation of the electronic signature data. COPYRIGHT: (C)2007,JPO&INPIT
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