| 摘要 |
1,062,130. Telegraphy. GRETAG A.G. Oct. 16, 1964 [Oct. 18, 1963], No. 42385/64. Heading H4P. In a ciphering system in which the cipher key is obtained from a counter and shift register arrangement, the counter is set prior to transmission by the action of a secret basic code and a code representing the date and time as determined by a quartz clock. The receiver also comprises a quartz clock, the secret basic code, and means to generate the cipher key for deciphering. In this way the cipher key at both transmitter and receiver is changed every minute. The cipher key developed depends upon the initial setting of the counter which is connected in feedback arrangement with shift registers. The counter may additionally be controlled by the output of a random generator. This output is sent to the receiver so that the counter there is set correspondingly, prior to the transmission of the ciphered data.
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