| 摘要 |
PROBLEM TO BE SOLVED: To provide an encryption system, a terminal device and an encrypting method which can prevent encrypted information from being decrypted before a designated time comes without rigidly managing the security of a time signal station when a so-called time capsule encryption is used. SOLUTION: This encryption system is provided with a plurality of time signal stations, and each of the time signal stations is provided with a time signal generating section for acquiring a multinominal for its own station assigned to the time signal station from another time signal station and generating a time signal with a complex electronic signature including the multinominal for it own station. The terminal device is provided with a time signal acquiring section for acquiring the predetermined number of time signals with complex electronic signatures, an entire signature data computing section for computing entire signature data corresponding to a designated time using a predetermined interpolation method on the basis of a predetermined multinominal included in the time signal with the complex electronic signature, and a decryption key generating section for generating a decryption key using the entire signature data. COPYRIGHT: (C)2007,JPO&INPIT
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