| 摘要 |
PURPOSE:To obtain a ciphering system with high secrecy by adopting the constitution that a key forming device is incorporated in a ciphering device, an open key is outputted to the outside of the ciphering device and the secret key is stored in the ciphering device and not outputted to the outside of the ciphering device. CONSTITUTION:When a key generation command comes to a command terminal 21, a control section 2 of the ciphering device 1 receives an external parameter for generating two keys at an input section 6, the keys are supplied respectively to registers 11, 12, a random number is extracted from a random number generator 3 and fed to a register 13, a key generating section 4 is started, and the selected secret key and common key are stored respectively in storage registers 14, 15 and the open key is fed to a register 16. The common key and the open ley are outputted respectively via a key output section 7. When a decoded command comes to the command terminal 21, the secret key and common key are moved to registers 17, 18, a ciphering message of a data 24 is received from a data input section 8, the ciphering message is decoded into a plain message by using the secret key and common key at a procesing section 5 and the result is handed over to a data output section 9. When the ciphered command comes to the command terminal 21, the processing section 5 ciphers the plain message of the data 24 and supplies the result to the output section 9. |
