CRYPTOSYSTEM, ENCRYPTING METHOD, MANAGEMENT STATION, TIME TONE STATION, TRANSMISSION TERMINAL AND RECEPTION TERMINAL

摘要

PROBLEM TO BE SOLVED: To provide a cryptosystem using a new time capsule encryption obtained by extending time capsule encryption. SOLUTION: A transmission terminal 3 generates encrypted information based on a management station public key, decryption time designating information indicating the time of decryption of transmission target information, target time tone station designating information indicating an optional or specific time tone station and transmission target information, and transmits the generated information to a reception terminal 4. The reception terminal 4 determines whether or not a signatured time tone is a correct time tone by using the management station public key. If the time tone is a correct time tone, the reception terminal 4 decrypts the encrypted information on the condition that the time tone station designating information and the time information included in the time tone have a predetermined relation with the target time tone station designating information and the decrypted time designating information included in the encrypted information. COPYRIGHT: (C)2009,JPO&INPIT