| 摘要 |
PROBLEM TO BE SOLVED: To make the eavesdropping of secret information difficult and to eliminate the danger of being deciphered any information is eavesdropped. SOLUTION: After digitizing the secret information to be sent and converting it to a bit string, the bit string is ciphered by a cipher key 5 by a ciphering device 1 and then, divided into two data in a division device 6. The two data are separately sent to a communication path (A) 3 and the communication path (B) 4. The two communication paths can be cable communication paths, the combination of cable and radio communication paths, the different channels of the radio communication path or the same channel of different time. After synthesizing the two ciphered data by using the cipher key in a synthesizer 7 on a reception side, they are restored to one plain sentence in a deciphering device 2. Ciphering and division (synthesis and deciphering) can be integrated. By a similar method, the data can be divided into two and stored in two storage devices or the different areas of the same storage device. Three or more communication paths or storage devices can be used as well. By dividing the data by the cipher key and transmitting them, even when a part is eavesdropped, the danger of being deciphered is eliminated unless all is eavesdropped.
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