Abstract: The machine involves code wheels in cascade or in a maze with random or mixed circuits which operate a printing device to print the cipher conjugate of the letter on an operated key when the keyboard is connected to one end of the code wheel maze, and to print the plain conjugate of the letter in cipher when a key bearing such letter is operated with the keyboard connected to the other end of the code wheel maze. The printer is connected to the end of the code wheel maze opposite the end to which the keyboard is connected in both cases.

Abstract: 1. Apparatus for producing multiple combinations of parallel output binary signals for controlling an anti-jam or other form of telegraphy system comprising four parallel feedback shift registers, a pair of serial to parallel converters, each having an input terminal, means for combining the output signals of said shift registers for producing two separate serial signals, means for coupling one of said serial signals to the input terminal of one of said converters, means for coupling the other of said serial signals to said input terminal of the other of said converters and means for changing the output signal of one of said converters when said separate signals are identical for a predetermined number of binary digits, said feedback shift registers having pluralities of separate stages and a feedback mixer having input terminals connected to the last and certain other three of said stages, and an output terminal connected to the first of said stages.

Abstract: 1.

Abstract: 1. A synchronous binary cryptographic system responsive to an input synchronous telegraph signal comprising means for generating timing pulses of substantially fixed, predetermined frequency, means for generating a synchronous binary cryptographic key in synchronism with timing pulses applied thereto by said means for generating timing pulses, switch means actuated by a predetermined input signal sequence for applying the timing pulses to said means for generating the binary cryptographic key, said cryptographic key generating means being continuously responsive to said timing pulses during operation of the system and means for combining said input signal with the cryptographic key.

Abstract: 1. A start/stop cryptographic telegraphy terminal-equipment comprising electronic means for generating clock pulses, means responsive to the clock pulses for generating timing pulses occurring at a substantially predetermined rate less than the occurrence rate at which said clock pulses are generated, means responsive to the generated timing pulses for generating a cryptographic-key signal and means for initiating the generating of the clock pulses in response to a telegraph start signal supplied to the equipment, said last named means including means for combining the telegraph and cryptographic-key signals. 31.