| 摘要 |
PROBLEM TO BE SOLVED: To provide a cipher communication, system high in information security even though plural callers exist for a specific callee by adopting the server, which specifically conducts a decoding having secret keys, along with a transmitter and a receiver. SOLUTION: A transmitter 110 ciphers a message M by an open key ciphering means 112 and open keys P and N generated by a server 130 and a ciphered message M0 is transmitted to a receiver 120 by a ciphered message transmitting means 114. The receiver 120 generates a random number X by a random number generating means 122, the message M0, which is transmitted from the transmitter 110, is further ciphered by the number X in a ciphering means 124 and the ciphered message M1 is transmitted to the server 130. The server 130 decodes the transmitted and ciphered message M1 in a decoding means 136 employing the keys. The decoded message M2 is returned to the receiver 120 by a decoded message transmitting means 138. |
