Abstract: 1. In secret telephony, means to analyze speech message waves into slowly varying currents representative of energy variations in respective portions of the speech frequency band, distributor means for rapidly switching fragments of said currents to line in rotation, a source of masing currents for each of said slowly varying currents, the masking currents each varying in magnitude in random manner, and synchronously operating means for adding masking current from a respective source to each fragment of the switched currents.

Abstract: 6. In a pulse generating system, means for producing irregular pulses in each of a number of separate circuits, an output for each of said circuits, a pair of holding devices for each of said circuits, means for connecting said holding devices one at a time to their respective circuits and means for combining pulses impressed on each of said outputs from said several circuits with other pulses from a corresponding one of said holding devices.

Abstract: 1. A signal value permuting system comprising a succession of reentry circuits having successively higher reentry point values, means to send signals through a plurality of said reentry circuits in tandem, and a key for each reentry circuit, means to add key and signal values together at the input side of each reentry circuit, each key having a range of values the maximum value of which is lower than the reentry point value of the reentry circuit with which the respective key is associated.

Abstract: 1. In a speech privacy transmission system, means for analyzing speech currents into component frequency band currents in a plurality of separate circuits, a corresponding plurality of separate transmission channels, a common keying circuit having an input side and an output side for keying each of said frequency band currents in succession, distributor means for connecting the input side of said keying circuit to each of said plurality of separate circuits in rotation to enable the frequency band currents therein to be keyed in succession, and distributor means for connecting the output side of said keying circuit to each of said plurality of transmission circuits in rotation to enable the keyed currents to be individually transmitted over said respective channels.

Abstract: 1. In combination, means for receiving a signal wave accompanied by a pilot impulse, means to combine with the received signal wave a locally produced wave in predetermined phase relation comprising means to produce a local pilot impulse in definite relation to said locally produced wave, signal storage means, means responsive to said first pilot impulse to enable said storage means to receive and store said signal wave, a signal responsive device, and means controlled by said local impulse to impress said stored signal wave upon said signal responsive device together with said locally produced wave.8. In a speech transmission system, means to sample input speech waves twice per cycle of the highest component frequency of the speech to be sent, means to produce pulses representative of the sampled speech equal in length to the time between sampling instants, means to combine said pulses with individual key pulses to disguise the speech pulses and means to transmit the combined pulses.

Abstract: 1. In a pulse-producing system, a plurality of space discharge tube ring circuits each comprising a different number of stages, the numbers of stages in the rings having no common factor greater than one, means to cause said rings to step in unison, means to derive output voltage pulses from certain stages of individual rings and spaces from the other stages, and means to combine the outputs of all of said rings in a common utilization circuit.

Abstract: 1. In a system of secret transmission of speech, means to subdivide speech waves constituting a message into a plurality of narrow frequency bands, means to integrate the energy in each band, means individual to said bands to subdivide the integrated energy from each band on a time basis to produce impulses with intervening spaces, and means to variably control said last-mentioned subdividing means individually in accordance with a key unrelated to the message.

Abstract: 1. A key generating circuit for constructing a six-valued key by combination of signals of smaller ranges of values comprising means to produce two-valued signals of highly irregular occurrence, one signal having the values 0 and 1 unit, and the other having the values 0 and 3 units, means to produce a three-valued signal having the values 0 and 2 and 4 units occurring in irregular sequence, means to combine all of said signals in additive manner, and means effective when the summation signal has the value 6 units or a greater value for reducing such value by 6 units.

Abstract: 1. In a signaling system, a plurality of input circuits carrying signal currents, a corresponding plurality of individual output channels, a privacy equipment common to said circuits and channels for rendering said signal currents unintelligible, a first set of relays for operatively associating said input circuits one at a time with said privacy equipment, a second set of relays for operatively associating said privacy equipment with said channels one at a time, and a common timing circuit for operating the relays of each set in timed sequence.

Abstract: 1. In a secret signaling system, means at a station for providing a plurality of different keys for use one at a time for enciphering signals to be sent from said station, means at said station when transmitting for sending a concomitant indication identifying the particular key that is in use in transmitting, means at a station when receiving secret signals and key indications from another station for providing a plurality of different keys which are duplicates of those provided at the distant sending station, means responsive to the received key indication for automatically selecting the appropriate key for deciphering the received secret signals, and means for deciphering said received secret signals by means of said selected key.

Abstract: 1. In secret telephony, means to analyze input speech waves into low frequency speech-defining currents simultaneously existent in a plurality of separate circuit paths, means to add secret key currents to each speech-defining current to produce summation currents, means for periodically measuring the magnitude of each summation current, means to indicate the magnitudes of said currents by code combinations of pulses of equal number having fixed amplitudes, means to impress each pulse of the code combinations existing at any one time upon a different individual line, and means to continually alter the order of the lines upon which said pulses are impressed.

Abstract: 1. In a signaling system for transmitting with secrecy signals of varying amplitude, means to encipher said signals comprising means to produce variable key currents and means to combine said signals with said key currents to produce for transmission combination signal and key currents, and means to modify the variable key current that is sent whenever the signal has zero value.

Abstract: 1. In a scrambling system for translating input message values into output currents of substantially random occurrence of values, separate message input circuits for each message value, separate output control circuits for determining each output current value, a plurality of key circuits crossing said message input circuits, means to apply key currents to respective key circuits on a substantially random basis, and means at each cross-over point between said message input circuits and key circuits for setting up a current condition in a corresponding one of said output control circuits to determine the value of output current.

Abstract: 1. In a privacy system in which the signals are divided into fragments on a time basis and the different fragments are delayed in transmission by different amounts to afford privacy, a timing means having a timing cycle divided into several periods, a relay individual to each period and individually operated during its respective period by said timing means, a plurality of delay devices to introduce delay into said signals, means controlled by said timing means to select a delay device for each timing period, and means jointly controlled by said relays and selecting means to operate the selected devices.

Abstract: 1. In a key pulse generating circuit for producing key pulses varying in amplitude in highly irregular manner, said pulses occurring at a given rate, means to generate high speed off-on pulses at a rate many times higher than said given rate in a plurality of separate paths, means to hold over certain of said off-on pulses into subsequent of said high speed pulse times, means to combine the pulses so held over with pulses subsequently generated in certain of said paths to form combination of said high speed pulses, and means to select and combine with one another to form one of the final key pulses occurring at said given rate, individual ones of said last-mentioned high speed pulses occurring at instants of time separated from one another by several of said high speed pulses while discarding the intervening high speed pulses.6.