Antonelli, Terry, Stout & Kraus, LLP
System and method for controlling disclosure time of information
A key managing system for implementing simultaneous disclosure of information. The invention includes an information transmitting apparatus which transmits a date and time at which secrecy protection of information is ended to a key controlling apparatus. The key controlling apparatus searches a key control table indicating a relation between decryption keys and decryption key disclosure dates & times for an encryption key that forms a pair in conjunction with a decryption key associated with the date & time transmitted by the information transmitting apparatus. The key controlling apparatus then transmits an encryption key found in the search to the information transmitting apparatus. The key controlling apparatus also discloses a decryption key for the present date & time to an information receiving apparatus in response to a request for a decryption key at a present date and time. The information transmitting apparatus, upon receipt of the encryption key, encrypts information by using the encryption key and then transmits the encrypted information to the information receiving apparatus. The date and time, at which secrecy protection of information is ended is appended to the encrypted information. The information receiving apparatus, upon the present date and time becoming coincident with the date and time appended to the received encrypted information, acquires a disclosed decryption key and decrypts the encrypted information by using the decryption key.
Hitachi, Ltd.
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H04H H04H H04L H04L
inventional inventional inventional inventional
Masato Hiromichi
Arai Ito