| 摘要 |
1,134,791. Data transmission systems. CSFCOMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. 25 Oct., 1966 [8 Nov., 1965], No. 47926/66. Heading H4P. In a ciphering or deciphering apparatus associated with a plurality of digital data channels, the channels are selected in turn and the cipher key is changed in sequence with the selection so that signals on any one channel are mixed only with an associated cipher key. The input channels feed respective input stores which are read out in turn to a mixing unit which also receives a key signal from a cipher generator. The mixing unit output is the required ciphered or deciphered data, and is passed to an appropriate one of a number of output stores, there being one such store per channel. When a signal on any one channel, e.g. C, has been ciphered or deciphered the corresponding cipher key signal is passed to a cipher store associated with channel C. When next the input channel C is selected, the associated cipher store passes the cipher signal stored therein to preset the cipher generator, which then generates the next cipher signal relevant to channel C for mixing with the signal on channel C. The input stores may be selected in a fixed sequence or as they become full, the output and cipher stores being selected in the corresponding order. |
