Patent GB-874890-A (GB)
Title: Electrical arrangements for the ciphering coded binary signals
IPC: H04L9/22
Filed: 1958-02-26
Abstract: 874,890. Secret system for telegraphic and like binary coded signals. TELEFUNKEN G.m.b.H. Feb. 26, 1958 [Feb. 26, 1957], No. 6306/58. Class 40(3) A ciphering system for signals in an equal-unit code for type-printing telegraphy, or for a quantized binary code representative of speech, comprises m ring counters having cycles with numbers of steps which are all different and prime to each other and a cipher store for the n units of the teleprinter or binary code in combination with a switch-over device having m inputs and n outputs, the arrangement being such that each of the m ring counter outputs can be connected by the switch device through a gate circuit to any of the n inputs of the cipher store. A start pulse to initiate the operation of the arrangement operates the receiving relay ER and its contact er so that an oscillator O operating at the element frequency controls a 5-stage counter V producing pulses which allow the signal elements at contact er to pass through gates a . . . e of an assembly T1 to the elements a . . . e of an adding device AW to which ciphering elements are passed from gates a . . . e of an assembly T2 after a delay produced by devices D1 in conjunction with pulses from the counter V. Pulses are also passed from the counter V with a delay T2 (>T1) to the tubes a ... e of an interrogating device AA which detects the pulses set up in the adding device AW and controls the output relay AR to pass the ciphered signal elements to the line AK. The ciphering pulses fed to the inputs A . . . E of the element T2 are derived by cross connection of the outputs I . . . V of storage elements of a cipher store SS controlled through predeterminedly set switches S1 . . . S10 and a set T3 of gates 1 ... 10 which are opened by pulses in succession from the elements 1... 10 of a tenposition counter SA and pulses produced by cyclically-operated counters Z1 . . . Z10 when they have been stepped to their respective final stages. The counter V, when it reaches its fifth, or final, stage after five signal elements have been received, passes a pulse over the line SL to all the counters Z1 . . . Z10 which are stepped to their final positions by 2, 3, 5, 7 ... 29 pulses respectivelythese numbers being all prime to each other. The output of the oscillator O is passed through a frequency doubler FV-so that the counter SA is stepped through a complete cycle during which the members 1 . . . 5 of the store SS are set, firstly according to the outputs of Z1 . . . Z5 and switches S1 . . . S5 and then by the outputs of Z6 . . . Z10 and the setting of the switches S6 . . . S10. Impulses from the counter or distributer V are also passed with delay provided by devices D2 to elements a ... e of an interrogating device AA operating to detect the pulses stored in the adding device AW to control the output relay AR passing the ciphered pulses to the line AK. The detecting pulses from the interrogator AA also restore the adding device to its normal condition to respond to the elements of the subsequent signal. The pulses from the doubler F# are slightly delayed by the device D3 to prevent coincidence of the setting pulse over SL with a stepping pulse to the distributor SA. In a modification, Fig. 2 (not shown), utilized for teleprinter signals, the oscillator O producing pulses timed with the incoming signal elements is controlled by the start and stop signal elements through a switch device which also provides a pulse over a conductor, corresponding to SL of Fig. 1, to step the set of ring-counters of different operational cycles. The switch device also provides a pulse which through suitable delay devices controls elements auxiliary to the tubes of the interrogator to add start and stop elements to the ciphered 5-unit code combination sent to the outgoing line.