GB1118671A - Reading device for cryptographic machine - Google Patents

Abstract

1,118,671. Ciphering. PHILIPS USFA N.V. 5 March, 1963 [6 March, 1962], No. 8826/63. Heading G5X. [Also in Division H4] A ciphering device comprises a group of key elements which can be stepped and which provide a " zero " or a " one " output, and means for adding the sum of the key element outputs to the signal input to provide an output signal. In Fig. 1 four key elements 1-4 are stepped irregularly and each occupies one of a prime number of states which indicate a " zero " or a " one ", the states being read by reading devices 9-12. A signal source 44 supplies a signal, which is either zero or one, through switch 81 to a bi-stable device 41 which adds the signal to the output of element 1, the addition law being that like signals produce zero output and unlike signals a " one " output. Similarly the output of device 41 is added in unit 42 to the output of element 2, and so on to produce a ciphered output at 82. In a modification, Fig. 3 (not shown), the outputs of elements 2 and 3 are added together and then added to the output of device 41. In a further modification, Fig. 4 (not shown), the outputs of pairs of elements 1 and 2 and 3 and 4 are added together and the two sums are then added together, the total being added to the input signal. In another modification, Fig. 5 (not shown), each of the elements 1-4 is provided with five separate reading devices feeding five bi-stable devices so that five input signals in parallel can be ciphered simultaneously. Reversing switches can be used instead of bi-stable devices, Fig. 6 (not shown). In another arrangement, Fig. 7, the outputs of elements 1-4 are applied to " and " gates 65-68, to each of which the signal from source 44 is applied in turn through a distributer 70. The outputs of the gates are added by a counter 69 which changes its state on receipt of a " one " input and is unaffected by a " zero " input. At the end of a cycle a pulse is applied at C to allow the output of counter 69 to pass through unit 110 to the output 82. The ciphered text or the plain text may be applied at 81 to " and " gate 83; then if the text and the source 44 are both " one " the gate 83 will supply a " one " to counter 69.