| 摘要 |
PROBLEM TO BE SOLVED: To make circulatable information to a receiver so that the information to be transmitted isn't known to a person excepting the receiver when the receiver of the information is decided with a third person by acquiring ciphering information from an information circulation controller with the receiver and deciphering the information with a common key supplied from the third person. SOLUTION: This information circulation controller consists of a certificate check part 13, an information storage part 14, an information extraction part 15 and an information preservation part 16. In this information circulation controller 1, the information transmitted to the receiver is ciphered with a cipher key generated by a transmitter, and the ciphered information is sent beforehand to a receiver group. Then, the common key is ciphered with the open key of the third person belonging to the third person group selecting the receiver to be transmitted, and the ciphered common key received by the third person is deciphered with the secret key of the third person, and the common key is taken out. Then, the common key is handed directly to the information receiver in the receiver group, and the information receiver receives the information ciphered with the common key by the transmitter from the information circulation controller 1 to decipher it.
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