US3773977A - Method of enciphered information transmission by time-interchange of information elements - Google Patents

Method of enciphered information transmission by time-interchange of information elements Download PDF

Info

Publication number
US3773977A
US3773977A US00154851A US3773977DA US3773977A US 3773977 A US3773977 A US 3773977A US 00154851 A US00154851 A US 00154851A US 3773977D A US3773977D A US 3773977DA US 3773977 A US3773977 A US 3773977A
Authority
US
United States
Prior art keywords
elements
store
pulses
register
signals
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00154851A
Other languages
English (en)
Inventor
G Guanella
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Patelhold Patenverwertungs and Elektro-Holding AG
Original Assignee
Patelhold Patenverwertungs and Elektro-Holding AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Patelhold Patenverwertungs and Elektro-Holding AG filed Critical Patelhold Patenverwertungs and Elektro-Holding AG
Application granted granted Critical
Publication of US3773977A publication Critical patent/US3773977A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/34—Bits, or blocks of bits, of the telegraphic message being interchanged in time
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K1/00—Secret communication
    • H04K1/06—Secret communication by transmitting the information or elements thereof at unnatural speeds or in jumbled order or backwards

Definitions

  • An information signal train which may, for example, be an audio signal, is divided into equal time intervals and temprarily stored. Each stored element is read out in a random pattern so as to randomly scramble the arrangement of the elements as compared with their original arrangement. The scrambling" of the elements is continuously monitored so as to prevent more than one element from being shifted to the same (new) time position and further to prevent any gaps in the transmitted signal train.
  • the process is effectively reversed at the receiving end which is provided with a similar random generating and deciphering means operating in synchronism with the enciphering means at the transmitter facility. Shifting of the element positions may be confined to a group containing a predetermined number of elements or alternatively may be progressively shifted to new positions without concern for limiting shifting in time of elements to a group of a predetermined number of elements.
  • Additional techniques may be employed to reverse polarity of selected elements or to randomly superimpose other signals upon selected ones of the elements in a random fashion.
  • the present invention relates to method and apparatus for transmitting data in enciphered fashion and more particularly relates to apparatus and method for enciphering information transmitted, in which the plain language signals to be transmitted are divided into elements of preferably equal time length whose original time sequence prior to transmission is modified by interchange and restored after transmission by a reverse process of interchange, the elements being in part at least interchanged (and the reverse process carried out at the receiving end) by dissimilar time shifts through the utilization of a storage process within an information store.
  • an object of the present invention is to overcome these drawbacks.
  • this is achieved in that the transmitting and receiving ends are provided with coinciding aperiodic cipher signals which are produced by cipher signal generators and supplied to ancillary devices whereby special control signals are derived from the cipher signals which are utilized to determine the storage positions of the individual elements in the information store; in that additional devices each containing an additional storage means serve as an occupation register in which binary pulses are stored, each of which is assigned to an information element; in that by means of hunting pulses (h) which depend in part at least upon the cipher signals,
  • the (state of) occupancy occupany of individual positions in the occupation register is modified in an irregular sequence in the sense that occupied positions are evacuated (or empty positions are occupied;) in that, when a hunting pulse tests a register position which has already undergone the aforesaid change in occupany, i.e., has either been evacuated (or occupied,) the hunting operation is continued for register positions which have not yet been changed in this manner, without further modification of the occupancy of any register position which is already changed; and in that, with any change in occupany, a control signal (i) is produced which determines the storage position of the corresponding element in the information store, so that automatic monitoring of the occupancy of the information as stored is achieved, whereby on the one hand, control signals which are required to avoid omissions of individual elements is insured, and on the other hand, control signals which lead to repetition of individual elements are suppressed.
  • first and second stores are provided which are capable of storing a predetermined number of elements of equal time length.
  • One of said stores is filled while the other is emptied and the process is then reversed whereby the store being emptied is emptied in such a manner as to interchange the positioning of the stored elements in an aperiodic fashion with monitoring means continuously monitoring the interchange operations so as to prevent the occurrence of overlapping or gaps in the interchanged signal train.
  • monitoring means continuously monitoring the interchange operations so as to prevent the occurrence of overlapping or gaps in the interchanged signal train. The process is reversed at the receiving end.
  • a single store is provided in which continuous interchange of the signal elements is performed.
  • Another object of the present invention is to provide a novel apparatus and method as described herein wherein the deciphering of the enciphered signal train occurs by a technique reverse from that set forth in the previous object.
  • FIG. I is the block diagram illustrating the fundamental principles of the invention.
  • FIG. 2a illustrates information signal wave forms showing the manner in which the wave form is broken down into individual elements and further illustrating the interchange and reversal of the individual signal elements;
  • FIG. 2b symbolically represents the interchange of signal elements at the transmitting end and the reverse operation at the receiving end;
  • FIG. 3a symbolically represents the principle of interchange of signal elements within equilength groups (leapfrogging window");
  • FIG. 3b schematically depicts another interchange principle which avoids closed groups (sliding window”);
  • FIG. 4 illustrates an example of a device for implementing the method of the invention, which device employs the group interchange technique
  • FIG. 5 is an examply of another variant embodiment of the invention with continuous interchange of signal elements
  • FIG. 6 schematically represents the mode of operation of the device shown in FIG. 5;
  • FIGS. 8a and 8b schematically represent the mode of operation of the device of FIG. 7;
  • FIG. 9 illustrates an example of the invention employing individual stores for the information store and separate occupation register for the individual information stores
  • FIG. 10 is a schematic illustration of the principle of time compression of the interchanged signal elements, prior to transmission
  • FIG. 11 shows the block diagram of a device for additional concealment signals which are added to the interchanged information signals
  • FIG. 12 illustrates the block diagram of a cipher signal generator employed in performing the method of the present invention
  • FIG. 13 is a detailed illustration of a portion of the cipher signal generator of FIG. 12.
  • FIG. 14 is a block diagram of the cipher computer employed in the cipher signal generator.
  • FIG. 1 there is shown therein a block diagram of an enciphering system in which at the transmitting end (Index I) and receiving end (Index 2) the cipher signal generators SG, and SG produce the aperiodic cipher signals w.
  • the plain language signal x may, in accordance with FIG. 2a, consist of a periodic train of oscillations, of the type, for example, occurring in a speech signal.
  • This signal is divided into the sections or elements (i.e., time intervals) s,, s,, of uniform length throughout and which generally have no fixed relationship to the periodicity of the signal.
  • These elements are stored for dissimilar times, for time-interchange purposes, so that a new signal 1 is produced.
  • the element has been produced by reversing the polarity of element 3,.
  • the plain language signal is already available in digital form or is otherwise placed in this form by an analog-to-digital conversion, then the elements" naturally consist of a specific number of bits, the number being the same in each element.
  • FIG. 2b The interchange of signal elements at the transmitting end and the reverse procedure of interchange at the receiving end, taking also into account the individual cases of reversal of polarity which lead to the pro duction of the s type elements are symbolically illustrated in FIG. 2b wherein the elements s,s, are interchanged in time so as to form the signal z,.
  • This signal is received as 12 by the receiving end and is processed in such a manner as to rearrange the individual elements to return the elements to their original arrangement, as shown symbolically by the signal arrangement
  • the interchange can take place within individual groups of elements of length F or can, for that matter, take place progressively, avoiding closed groups, as shown in FIG. 3b.
  • each individual element is in each case restricted to the cross-hatched area which, in the case of FIG. 3a, leapfrogs (leapfrogging window technique) from group to group, or as in the case of FIG. 3b, shifts from element to element (sliding window technique).
  • a device SM for producing time-interchange between the elements of a plain language signal x, as well as an additional device ZE for producing the control signals 1' for this interchange function, are shown in FIG. 4. These control signals must be derived from the aperiodic cipher signal w of the cipher signal generator SG, in such a way that in the interchange operation, no repetitions and omissions occur.
  • Each element of the plain language signal x will be assumed for example, to consist of a train of k analogue pulses (scanned values), which have been obtained by periodic scanning of the original signals.
  • a group of, for example, six elements for six k scanned values of the plain laungauge signal is then supplied via the double-throw switch W, to the analogue shift store NS, which is comprised of six k cells.
  • the transfer through the register during the introduction of these scanned values is effected by pulsing signals e which are applied through switch W
  • the elements of the previous group already stored in NS (which is substantially identical in design and operation to NS,), are extracted in the modified sequence through the output switch W,.
  • the doublethrow switches W and W are so designed that a control pulse i,, for example, with W, in the solid line position illustrated in FIG.
  • the other elements are extracted in a sequence which is determined by the control signal 1'. During the extraction operation, gaps and repetitions must be avoided.
  • the device ZE is provided with an occupation store BS.
  • the six cells of this store are initially filled by the pulse t with the commencement of each sixth element group, and is subsequently individually emptied by the hunting pulses h.
  • the hunting pulses are produced from the cipher signals y,, y,, y, of the cipher signal generator SG,
  • a change pulse e reverses the state of switches W through W
  • the shift store NS is filled with elements of the plain language signal while the elements of the store NS which has previously been filled, are extracted in a changed sequence.
  • the interchange between the information elements thus takes place in group fashion in accordance with the leapfrogging window principle of FIG. 3a.
  • the pulse output w and device VM of FIG. 4 are employed as an additional enciphering device, as will be described in greater detail hereinbelow.
  • FIG. 5 A device for the continuous interchange of signal elements in accordance with the sliding window principle of FIG. 3b is shown in FIG. 5.
  • information store NS once again an analog shift store can be used or for that matter some other known delay system with several supply or extraction points may be employed.
  • the supply of the elements r,, r, of the plain language signal 1:, is controlled by the switches U U in accordance with the actuation by control signals d,, 11,, whose sequence must again satisfy special conditions in order to avoid repetitions and omissions.
  • the occupation register BR is provided in association with hunting switches 8,, 8,,
  • the information register contains the monitored cells indicated in cross-hatched fashion while the additional cells are designed as unmonitored shift cells in order to reduce the complexity of the system.
  • the cell content is shifted in rhythm with the pulsing signal e which corresponds with the pulsed rate of the individual signal elements.
  • the still empty left-hand end of the register can be occupied cell by cell by the pulses d d and the occupancy is checked by the monitoring signals b,. If the last cell P in the register is still empty, the absent occupation pulse b, has the result that from the periodic pulse train r: an individual pulse d, is extracted and supplied to this cell so that the latter two are filled.
  • the individual pulse is supplied as a pulse c, to the hunting switch 8,.
  • This switch is once again controlled by any occupation pulse b, which arrives and also by the blocking pulse a which occurs with a probability of A It is only the simultaneous absence of a and b that the storage cell P is filled by a pulse (1,. Otherwise, a transmission pulse 0 is supplied to the hunting switch 8;, so that monitoring is repeated. Any transmission pulse c, coming from the switch S finally, if necessary, fills the initially always empty first cell P of the register.
  • the function of the hunting switch obeys the following logic relationships, where the bar in each case indicates the negation condition:
  • the cipher signal converter marked SW can be used and is made up of the logic gates L, (logic OR”) and L,, (logic AND) as is shown in FIG. 5. Precise adherence to these probability values is of course generally not necessary and thus simpler circuits can be employed to produce the desired blocking signals.
  • the reference KS refers to the plain language signal, G, the group (of information elements in the plain language signal), VS the interchanged signal, SpGr the storage group (in the information store), INr, the internal number (of the storage position within a group), FNr the serial (of the information store positions).
  • the elements of the plain language signal (KS) are sequentially numbered (righthand margin) and are also ordered in groups of four elements each.
  • Element 4 passes via a switch U, (FIG. 5) to the store and is there recorded at position 17 on the moving data carrier NS.
  • Element 5 of the plain language signal passes, after four pulses of the pulsing signal, via switch U, to the data carrier which has in the meantime advanced four steps; i.e., it is not recorded at position 5 on the data carrier, which position was originally disposed at this location, but at position (5+4) 9.
  • the position fixed in relation to the apparatus is, in each case, marked by a square (with the element number) and the coordinate relating to the data carrier by a circle (with the element number).
  • element 9 is recorded at position 17 (of the apparatus) and at position (of the data carrier) and so on.
  • element No. 2 of the plain language signal is once again supplied by a switch U, to the data carrier which is now, however, moved by one step so that the element arrives at position 6 on the data carrier instead of position 5.
  • FIG. 5 it is also possible to work with several circulating carriers which, for example, may take the form of magnetic tape wheels or magnetic drums M,, M which are driven through a common shaft as shown in FIG. 7. ln order to select the eligible storage positions, once again an occupational register BR with associated hunting switches S,, S, can be used.
  • the control pulses consequently produced would primarily be suitable for producing an effective recording upon the continuously moving data carrier.
  • the rotating data carriers are assigned a data carrier of this kind in such a way that on M, the four elements of a first group of the moving carrier are stored, on M the four elements of the second group, and so forth.
  • the supply to the storage wheel memory devices must be progressively switched so that said relationship is maintained.
  • the additional shift register HR is provided, through which the position pulses d are transmitted.
  • the first four position pulses can be relayed directly in the form of corresponding control pulses i.
  • the next group of four position pulses must, however, be moved one step to the left in HR, so that a recording, which, for example, by way of U would take place in group 5 of the tape which has meanwhile been moved, now takes place through store M which corresponds to this group.
  • the next four position pulses which thus correspond to the third group of the plain language signal, must be shifted two places to the left HR, and so on.
  • Signal extraction from the source M M is controlled by extraction pulses I k from the register HR through which circulates a single control pulse so that if the control pulses k,, k,, Extraction shifts from store to store and takes place at the same locations on the rotating data carriers, as would correspond to scanning of a continuously transfer data carrier in fixed relationship to the equipment.
  • FIG. 8a The effect of this type of recording can best be appreciated from FIG. 8a.
  • the references to this figure correspond to those of FIG. 6 except that in the case of VS (interchanged signals) the designation SpGr (store group) has been replaced by Sp (store), since we are now dealing with individual stores.
  • the recording control program i.e., the sequence of the control pulses d, is, in this case, the same as in the arrangements of FIGS. 5 and 6. Because of the aforesaid additional shifts, however, the recording positions (marked by squares) which are fixed in relation to the equipment, i.e., the numbers of the individual rotating stores appear at the shifted locations indicated by the arrowhead lines.
  • element 5 of the plain language signal is routed not by way of switch U, but instead by way of switch U and is stored in M (See FIG. 7).
  • the recording position (in a fixed relationship to the equipment) of the plain language element 6 has an additional left-hand displacement (marked by the square).
  • the storage positions of the rotating data carriers occur in this illustration in the oblique zones as drawn in, for example, for store M
  • the first occasion of occupation is, in each case, marked by the circled number of the original element, while the corresponding continuing occupancy is simply marked by circles.
  • the shift register HR for insuring the additional shifts is drawn in at the bottom edge.
  • FIG. 8b The extraction of the stored elements from the register is illustrated in FIG. 8b where the occupancies of the stored positions are once again indicated by the encircled numbers and then by dots. Since recording commenced with plain language element No. 1, in the first extraction cycle individual storage positions still remain unoccupied. Extraction takes place successively from store M M,, and so forth. It is in each case indicated by cross-hatching of the first group position corresponding to the read-out head. The movement of the storage positions beneath the read-out head is indicated by the horizontal arrows. The progressive extraction times correspond to the numbering at the righthand margin, and it can be seen from this that the extracted elements appear in the same interchanged sequence as in FIG. 6.
  • FIG. 9 Another interchange device for several data carriers M,, M is illustrated in FIG. 9.
  • separate occupation registers BR BR are provided for the individual stores, whose outputs are returned to their inputs via the respective switches W W thus indicating the maintenance of the occupation condition over several cycles.
  • An auxiliary register HR is occupied by 3 circulating pulses which in each case bring about the closure of 3 associated switches, e.g.
  • the devices in the indicated examples are suitable without further explanation for performing the reverse process of interchange of the signal elements at the receiving end, the ciphered signals z; being supplied via the leads indicated and the reverse-interchanged signals 1:: being extracted at the points shown.
  • the functions of supply and extraction of the elements to and from the stores are simply exchanged. With magnetic storage, erasing will conveniently be carried out directly by the new recording. However, an additional erasing function can be provided which comes into operation directly after signal extraction.
  • the time of compression of the individual storage elements or of the scanned values contained in an element is possible.
  • the individual elements s*,, s* of the cipher signal of FIG. 10 are produced. This achieves the result that the linear distortions of the transmission channel do not produce any unwanted cross-talk between the positionally displaced elements.
  • plainlanguage signals are recovered and the time-dispersion of the transmission channel has no undesired effects in this context. Compression is achieved by the use of pulsing signals e of somewhat higher frequency than the signals e, (See FIG. 4), i.e., by extracting the individual elements from the stores at a slightly faster rate. Similarly, eiement expansion at -the receiving end is achieved by somewhat slower extraction from the stores.
  • One highly effective measure to render the detection of associated elements more difficult consists in the addition of specific concealment signals at the transmitting end, which signals, with undistorted transmission, can be subtracted again at the receiving end.
  • These concealment signals may conveniently be obtained from special cipher signals using a digital-analogue converter, possibly coupled with shaping by special filters.
  • This kind of device with the digital-analogue converter D/A and the filter BP, is shown in FIG. 11. Besides this concealment signal condition DM and the position modulator LM, once again a sign modulator VM is indicated.
  • the cipher generator SG used to produce the cipher pulses can, as FIG. 12 shows, consist of a program signal generator PG, a cipher selector SE and a cipher computer SC.
  • the programme signals u are generated in the programme signal generator in accordance with a specific logic law, e.g., using a shift register, whose output pulses, taken from two points, are fed back via a modulo-2 logic system and the switch S shown in FIG. 13 to the input. Synchronization with transmitted programme pulses g is made possible by initial injection of this pulse train through the switch S until the fedback pulses coincide completely with the new incoming pulses. This condition is detected by the correlator KO which then automatically switches S to the feedback position for further operation on its own.
  • the present invention provides the method for interchanging signal elements of a transmitted message in a non-unifonn manner wherein the transposed signal elements are introduced into new time slots wherein the monitoring technique employed assures the fact that there is no overlapping of signal elements nor are any gaps provided.
  • a method of enciphered information transmission in which the plain'language signals to be transmitted are split up into elements of equal length whose original time sequence is modified by interchange prior to transmission and restored after transmission by a reverse process of interchange, the elements interchanged (and the reverse process carried out at the receiving end) through a process of storage in an information store, characterized by the steps at transmitting and receiving ends of: (a) generating coinciding aperiodic cipher signals (w); (b) generating control signals (1' FlG.
  • each storage position in the multi-position store corresponds with a specific position in the information store (NS); in that the number of multiposition store positions corresponds with the number of elements in a group; in that at the commencement of element interchange in a group, all positions in the multi-position store operating as occupation register have the same occupancy, i.e., all are occupied or all are free; in that with any modification of the occupancy of a register position by a corresponding control signal (1'), a corresponding position (corresponding, that is to this register position), in the information store is determined; and in that the number of the associated register position, which number is assigned to said hunting pulses, is formed in accordance with the rules of binary addition, from several pulses of the cipher signal.
  • a method as claimed in claim 1 characterized in that the information store (NS) consists of several individual independent stores operating in synchronism (M M,, FIG. 7); and in that the control signals for driving the associated individual stores are displaced by varying amounts, through additional registers (HR).
  • the information store (NS) consists of several individual stores; in that the occupation register (BR, FIG. 7) consists of several individual registers; in that in the hunting operation, the individual occupation registers are successively tested as to their binary states; and in that each new hunting pulse commences with the particular individual register next in succession.
  • each individual information store and each individual occupation register has several positions; and in that in the hunting operation a position in each occupation register is tested and in the ensuing hunting pulse a position in each individual occupation register is tested (FIG. 9).
  • a method as claimed in claim 13 characterized in that with changing directions of information transmission, recording and extraction in and from the information store change correspondingly, although the driving of the storage positions remains the same.
  • SC cipher computer

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Storage Device Security (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Signal Processing For Digital Recording And Reproducing (AREA)
US00154851A 1970-07-07 1971-06-21 Method of enciphered information transmission by time-interchange of information elements Expired - Lifetime US3773977A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1022770A CH518658A (de) 1970-07-07 1970-07-07 Verfahren zur verschlüsselten Nachrichtenübermittlung durch zeitliche Vertauschung von Informationselementen

Publications (1)

Publication Number Publication Date
US3773977A true US3773977A (en) 1973-11-20

Family

ID=4360828

Family Applications (1)

Application Number Title Priority Date Filing Date
US00154851A Expired - Lifetime US3773977A (en) 1970-07-07 1971-06-21 Method of enciphered information transmission by time-interchange of information elements

Country Status (12)

Country Link
US (1) US3773977A (enrdf_load_stackoverflow)
JP (1) JPS583426B1 (enrdf_load_stackoverflow)
AT (1) AT327293B (enrdf_load_stackoverflow)
BE (1) BE769493A (enrdf_load_stackoverflow)
CH (1) CH518658A (enrdf_load_stackoverflow)
DE (1) DE2046630C3 (enrdf_load_stackoverflow)
DK (1) DK133649B (enrdf_load_stackoverflow)
ES (1) ES392921A1 (enrdf_load_stackoverflow)
FR (1) FR2101561A5 (enrdf_load_stackoverflow)
GB (1) GB1356970A (enrdf_load_stackoverflow)
NL (1) NL167818C (enrdf_load_stackoverflow)
SE (1) SE363946B (enrdf_load_stackoverflow)

Cited By (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3921151A (en) * 1971-06-21 1975-11-18 Patelhold Patentwerwertungs & Apparatus for enciphering transmitted data by interchanging signal elements of the transmitted data without overlapping or omitting any elements within the transmitted signal train
US3991271A (en) * 1972-09-29 1976-11-09 Datotek, Inc. Voice security method and system
US4004089A (en) * 1975-02-28 1977-01-18 Ncr Corporation Programmable cryptic device for enciphering and deciphering data
US4020285A (en) * 1972-09-29 1977-04-26 Datotek, Inc. Voice security method and system
US4087626A (en) * 1976-08-04 1978-05-02 Rca Corporation Scrambler and unscrambler for serial data
US4099027A (en) * 1976-01-02 1978-07-04 General Electric Company Speech scrambler
US4100374A (en) * 1977-04-11 1978-07-11 Bell Telephone Laboratories, Incorporated Uniform permutation privacy system
US4160123A (en) * 1975-02-26 1979-07-03 Patelhold Patentverwertungs- & Elektro-Holding Ag Methods of and apparatus for the encoded transmission of information
US4217469A (en) * 1977-03-15 1980-08-12 Emilio Martelli Coding and decoding apparatus for the protection of communication secrecy
US4232194A (en) * 1979-03-16 1980-11-04 Ocean Technology, Inc. Voice encryption system
US4232193A (en) * 1977-05-12 1980-11-04 The Marconi Company Limited Message signal scrambling apparatus
US4266243A (en) * 1979-04-25 1981-05-05 Westinghouse Electric Corp. Scrambling system for television sound signals
US4278840A (en) * 1979-03-23 1981-07-14 Datotek, Inc. Dynamic frequency and time voice encryption system and method
US4295223A (en) * 1979-04-25 1981-10-13 Westinghouse Electric Corp. Digital signal/noise ratio amplifier apparatus for a communication system
US4302628A (en) * 1979-04-20 1981-11-24 Etablissement Publre Telediffusion De France Analog signal encrypting and decrypting system
US4318125A (en) * 1979-04-25 1982-03-02 Westinghouse Electric Corp. Solid state digital audio scrambler system for teletransmission of audio intelligence through a television system
US4433211A (en) * 1981-11-04 1984-02-21 Technical Communications Corporation Privacy communication system employing time/frequency transformation
US4550222A (en) * 1981-09-28 1985-10-29 Siemens Aktiengesellschaft Process for interception-protected frequency band compressed transmission of speech signals
US4551580A (en) * 1982-11-22 1985-11-05 At&T Bell Laboratories Time-frequency scrambler
US4591673A (en) * 1982-05-10 1986-05-27 Lee Lin Shan Frequency or time domain speech scrambling technique and system which does not require any frame synchronization
US4602283A (en) * 1982-10-25 1986-07-22 Cselt - Centro Studi E Laboratori Telecomunicazioni S.P.A. System for spatially and temporally transposing data words arrayed in periodically recurring patterns
US4608456A (en) * 1983-05-27 1986-08-26 M/A-Com Linkabit, Inc. Digital audio scrambling system with error conditioning
US4627074A (en) * 1982-02-26 1986-12-02 Siemens Aktiengesellschaft Method and arrangement for transmitting characters
US4638357A (en) * 1984-01-20 1987-01-20 Home Box Office, Inc. Audio scrambler
US4661980A (en) * 1982-06-25 1987-04-28 The United States Of America As Represented By The Secretary Of The Navy Intercept resistant data transmission system
US5253296A (en) * 1991-11-26 1993-10-12 Communication Electronics System for resisting interception of information
US5335277A (en) * 1981-11-03 1994-08-02 The Personalized Mass Media Corporation Signal processing appparatus and methods
EP1327937A4 (en) * 2000-09-20 2004-05-12 Yutaka Yasukura ELECTRONIC INFORMATION EDITING / RESTORING METHOD
US20040196971A1 (en) * 2001-08-07 2004-10-07 Sascha Disch Method and device for encrypting a discrete signal, and method and device for decrypting the same
US7769344B1 (en) 1981-11-03 2010-08-03 Personalized Media Communications, Llc Signal processing apparatus and methods
US20110182421A1 (en) * 2005-09-26 2011-07-28 Ternarylogic Llc Encipherment of digital sequences by reversible transposition methods
USRE47642E1 (en) 1981-11-03 2019-10-08 Personalized Media Communications LLC Signal processing apparatus and methods

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH574692A5 (enrdf_load_stackoverflow) * 1973-02-13 1976-04-15 Gretag Ag
CH558993A (de) * 1973-03-19 1975-02-14 Patelhold Patentverwertung Verfahren und einrichtung zur verschluesselten nachrichtenuebertragung.
CH559483A5 (enrdf_load_stackoverflow) * 1973-06-12 1975-02-28 Patelhold Patentverwertung
CH580893A5 (enrdf_load_stackoverflow) * 1973-07-02 1976-10-15 Gretag Ag
DE2339685C2 (de) * 1973-08-06 1982-06-03 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Schaltungsanordnung zum verschleierten Übertragen von Nachrichtensignalen
DE2359673C2 (de) * 1973-11-30 1982-05-27 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Verfahren zum Verschleiern des Informationsinhaltes von Frequenzbändern
DE2426635A1 (de) * 1974-06-01 1975-12-11 Licentia Gmbh Verfahren zum verschleiern des informationsinhaltes von frequenzbaendern
CH578807A5 (enrdf_load_stackoverflow) * 1974-11-05 1976-08-13 Patelhold Patentverwertung
DE2455477C3 (de) * 1974-11-23 1982-08-26 TE KA DE Felten & Guilleaume Fernmeldeanlagen GmbH, 8500 Nürnberg Verfahren zur Sprachverschleierung durch zeitliches Vertauschen der Sprachabschnitte
CH607506A5 (enrdf_load_stackoverflow) * 1976-06-01 1978-12-29 Europ Handelsges Anst
DE2809719C3 (de) * 1978-03-07 1985-03-14 Felten & Guilleaume Fernmeldeanlagen GmbH, 8500 Nürnberg Verfahren zur Erhöhung der Sicherheit gegen unbefugte Rückschlüsselung von verschlüsselter Sprache
US4642688A (en) * 1983-06-24 1987-02-10 Scientific Atlanta, Inc. Method and apparatus for creating encrypted and decrypted television signals
US5412719A (en) * 1992-01-17 1995-05-02 Hitachi, Ltd. Radio paging system with voice transfer function and radio pager

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1953918A (en) * 1932-03-28 1934-04-10 Associated Electric Lab Inc Cryptographic system and apparatus
US2453659A (en) * 1941-09-05 1948-11-09 Gutzwiller & Co E Secret telegraph signaling
US2547515A (en) * 1949-06-23 1951-04-03 Teletype Corp Secrecy system
US3657699A (en) * 1970-06-30 1972-04-18 Ibm Multipath encoder-decoder arrangement

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1953918A (en) * 1932-03-28 1934-04-10 Associated Electric Lab Inc Cryptographic system and apparatus
US2453659A (en) * 1941-09-05 1948-11-09 Gutzwiller & Co E Secret telegraph signaling
US2547515A (en) * 1949-06-23 1951-04-03 Teletype Corp Secrecy system
US3657699A (en) * 1970-06-30 1972-04-18 Ibm Multipath encoder-decoder arrangement

Cited By (137)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3921151A (en) * 1971-06-21 1975-11-18 Patelhold Patentwerwertungs & Apparatus for enciphering transmitted data by interchanging signal elements of the transmitted data without overlapping or omitting any elements within the transmitted signal train
US3991271A (en) * 1972-09-29 1976-11-09 Datotek, Inc. Voice security method and system
US4020285A (en) * 1972-09-29 1977-04-26 Datotek, Inc. Voice security method and system
US4160123A (en) * 1975-02-26 1979-07-03 Patelhold Patentverwertungs- & Elektro-Holding Ag Methods of and apparatus for the encoded transmission of information
US4004089A (en) * 1975-02-28 1977-01-18 Ncr Corporation Programmable cryptic device for enciphering and deciphering data
US4099027A (en) * 1976-01-02 1978-07-04 General Electric Company Speech scrambler
US4087626A (en) * 1976-08-04 1978-05-02 Rca Corporation Scrambler and unscrambler for serial data
US4217469A (en) * 1977-03-15 1980-08-12 Emilio Martelli Coding and decoding apparatus for the protection of communication secrecy
US4100374A (en) * 1977-04-11 1978-07-11 Bell Telephone Laboratories, Incorporated Uniform permutation privacy system
US4232193A (en) * 1977-05-12 1980-11-04 The Marconi Company Limited Message signal scrambling apparatus
US4232194A (en) * 1979-03-16 1980-11-04 Ocean Technology, Inc. Voice encryption system
US4278840A (en) * 1979-03-23 1981-07-14 Datotek, Inc. Dynamic frequency and time voice encryption system and method
US4302628A (en) * 1979-04-20 1981-11-24 Etablissement Publre Telediffusion De France Analog signal encrypting and decrypting system
US4266243A (en) * 1979-04-25 1981-05-05 Westinghouse Electric Corp. Scrambling system for television sound signals
US4295223A (en) * 1979-04-25 1981-10-13 Westinghouse Electric Corp. Digital signal/noise ratio amplifier apparatus for a communication system
US4318125A (en) * 1979-04-25 1982-03-02 Westinghouse Electric Corp. Solid state digital audio scrambler system for teletransmission of audio intelligence through a television system
US4550222A (en) * 1981-09-28 1985-10-29 Siemens Aktiengesellschaft Process for interception-protected frequency band compressed transmission of speech signals
US9043859B1 (en) 1981-11-02 2015-05-26 Personalized Media Communications, Llc Signal processing apparatus and methods
US7861263B1 (en) 1981-11-03 2010-12-28 Personalized Media Communications, Llc Signal processing apparatus and methods
US7908638B1 (en) 1981-11-03 2011-03-15 Personalized Media Communications LLC Signal processing apparatus and methods
USRE48682E1 (en) 1981-11-03 2021-08-10 Personalized Media Communications LLC Providing subscriber specific content in a network
USRE48633E1 (en) 1981-11-03 2021-07-06 Personalized Media Communications LLC Reprogramming of a programmable device of a specific version
USRE48565E1 (en) 1981-11-03 2021-05-18 Personalized Media Communications LLC Providing a subscriber specific solution in a computer network
USRE48484E1 (en) 1981-11-03 2021-03-23 Personalized Media Communications, Llc Signal processing apparatus and methods
US10715835B1 (en) 1981-11-03 2020-07-14 John Christopher Harvey Signal processing apparatus and methods
USRE47968E1 (en) 1981-11-03 2020-04-28 Personalized Media Communications LLC Signal processing apparatus and methods
US5335277A (en) * 1981-11-03 1994-08-02 The Personalized Mass Media Corporation Signal processing appparatus and methods
US5887243A (en) * 1981-11-03 1999-03-23 Personalized Media Communications, L.L.C. Signal processing apparatus and methods
US10616638B1 (en) 1981-11-03 2020-04-07 Personalized Media Communications LLC Signal processing apparatus and methods
US10609425B1 (en) 1981-11-03 2020-03-31 Personalized Media Communications, L.L.C. Signal processing apparatus and methods
USRE47867E1 (en) 1981-11-03 2020-02-18 Personalized Media Communications LLC Signal processing apparatus and methods
US7734251B1 (en) 1981-11-03 2010-06-08 Personalized Media Communications, Llc Signal processing apparatus and methods
US7747217B1 (en) 1981-11-03 2010-06-29 Personalized Media Communications, Llc Signal processing apparatus and methods
US7752649B1 (en) 1981-11-03 2010-07-06 Personalized Media Communications, Llc Signal processing apparatus and methods
US7752650B1 (en) 1981-11-03 2010-07-06 Personalized Media Communications, Llc Signal processing apparatus and methods
US7761890B1 (en) 1981-11-03 2010-07-20 Personalized Media Communications, Llc Signal processing apparatus and methods
US7764685B1 (en) 1981-11-03 2010-07-27 Personalized Media Communications, L.L.C. Signal processing apparatus and methods
US7769344B1 (en) 1981-11-03 2010-08-03 Personalized Media Communications, Llc Signal processing apparatus and methods
US7769170B1 (en) 1981-11-03 2010-08-03 Personalized Media Communications, Llc Signal processing apparatus and methods
US7774809B1 (en) 1981-11-03 2010-08-10 Personalized Media Communications, Llc Signal processing apparatus and method
US7783252B1 (en) 1981-11-03 2010-08-24 Personalized Media Communications, Llc Signal processing apparatus and methods
US7784082B1 (en) 1981-11-03 2010-08-24 Personalized Media Communications, Llc Signal processing apparatus and methods
US7793332B1 (en) 1981-11-03 2010-09-07 Personalized Media Communications, Llc Signal processing apparatus and methods
US7797717B1 (en) 1981-11-03 2010-09-14 Personalized Media Communications, Llc Signal processing apparatus and methods
US7801304B1 (en) 1981-11-03 2010-09-21 Personalized Media Communications, Llc Signal processing apparatus and methods
US7805738B1 (en) 1981-11-03 2010-09-28 Personalized Media Communications, Llc Signal processing apparatus and methods
US7805748B1 (en) 1981-11-03 2010-09-28 Personalized Media Communications, Llc Signal processing apparatus and methods
US7805749B1 (en) 1981-11-03 2010-09-28 Personalized Media Communications, Llc Signal processing apparatus and methods
US7810115B1 (en) 1981-11-03 2010-10-05 Personalized Media Communications, Llc Signal processing apparatus and methods
US7814526B1 (en) 1981-11-03 2010-10-12 Personalized Media Communications, Llc Signal processing apparatus and methods
US7817208B1 (en) 1981-11-03 2010-10-19 Personalized Media Communications, Llc Signal processing apparatus and methods
US7818778B1 (en) 1981-11-03 2010-10-19 Personalized Media Communications, Llc Signal processing apparatus and methods
US7818777B1 (en) 1981-11-03 2010-10-19 Personalized Media Communications, Llc Signal processing apparatus and methods
US7818761B1 (en) 1981-11-03 2010-10-19 Personalized Media Communications, Llc Signal processing apparatus and methods
US7818776B1 (en) 1981-11-03 2010-10-19 Personalized Media Communications, Llc Signal processing apparatus and methods
US7823175B1 (en) 1981-11-03 2010-10-26 Personalized Media Communications LLC Signal processing apparatus and methods
US7827587B1 (en) 1981-11-03 2010-11-02 Personalized Media Communications, Llc Signal processing apparatus and methods
US7827586B1 (en) 1981-11-03 2010-11-02 Personalized Media Communications, Llc Signal processing apparatus and methods
US7831204B1 (en) 1981-11-03 2010-11-09 Personalized Media Communications, Llc Signal processing apparatus and methods
US7830925B1 (en) 1981-11-03 2010-11-09 Personalized Media Communications, Llc Signal processing apparatus and methods
US7836480B1 (en) 1981-11-03 2010-11-16 Personalized Media Communications, Llc Signal processing apparatus and methods
US7840976B1 (en) 1981-11-03 2010-11-23 Personalized Media Communications, Llc Signal processing apparatus and methods
US7844995B1 (en) 1981-11-03 2010-11-30 Personalized Media Communications, Llc Signal processing apparatus and methods
US7849480B1 (en) 1981-11-03 2010-12-07 Personalized Media Communications LLC Signal processing apparatus and methods
US7849479B1 (en) 1981-11-03 2010-12-07 Personalized Media Communications, Llc Signal processing apparatus and methods
US7849493B1 (en) 1981-11-03 2010-12-07 Personalized Media Communications, Llc Signal processing apparatus and methods
US7856650B1 (en) 1981-11-03 2010-12-21 Personalized Media Communications, Llc Signal processing apparatus and methods
US7856649B1 (en) 1981-11-03 2010-12-21 Personalized Media Communications, Llc Signal processing apparatus and methods
US10523350B1 (en) 1981-11-03 2019-12-31 Personalized Media Communications LLC Signal processing apparatus and methods
US7861278B1 (en) 1981-11-03 2010-12-28 Personalized Media Communications, Llc Signal processing apparatus and methods
US7860131B1 (en) 1981-11-03 2010-12-28 Personalized Media Communications, Llc Signal processing apparatus and methods
US7860249B1 (en) 1981-11-03 2010-12-28 Personalized Media Communications LLC Signal processing apparatus and methods
US7864956B1 (en) 1981-11-03 2011-01-04 Personalized Media Communications, Llc Signal processing apparatus and methods
US7865920B1 (en) 1981-11-03 2011-01-04 Personalized Media Communications LLC Signal processing apparatus and methods
US7864248B1 (en) 1981-11-03 2011-01-04 Personalized Media Communications, Llc Signal processing apparatus and methods
US7870581B1 (en) 1981-11-03 2011-01-11 Personalized Media Communications, Llc Signal processing apparatus and methods
US7889865B1 (en) 1981-11-03 2011-02-15 Personalized Media Communications, L.L.C. Signal processing apparatus and methods
USRE47642E1 (en) 1981-11-03 2019-10-08 Personalized Media Communications LLC Signal processing apparatus and methods
US7926084B1 (en) 1981-11-03 2011-04-12 Personalized Media Communications LLC Signal processing apparatus and methods
US7940931B1 (en) 1981-11-03 2011-05-10 Personalized Media Communications LLC Signal processing apparatus and methods
US7953223B1 (en) 1981-11-03 2011-05-31 Personalized Media Communications, L.L.C. Signal processing apparatus and methods
US10334292B1 (en) 1981-11-03 2019-06-25 Personalized Media Communications LLC Signal processing apparatus and methods
US9674560B1 (en) 1981-11-03 2017-06-06 Personalized Media Communications LLC Signal processing apparatus and methods
US9294205B1 (en) 1981-11-03 2016-03-22 Personalized Media Communications LLC Signal processing apparatus and methods
US7992169B1 (en) 1981-11-03 2011-08-02 Personalized Media Communications LLC Signal processing apparatus and methods
US8046791B1 (en) 1981-11-03 2011-10-25 Personalized Media Communications, Llc Signal processing apparatus and methods
US8060903B1 (en) 1981-11-03 2011-11-15 Personalized Media PMC Communications, L.L.C. Signal processing apparatus and methods
US8112782B1 (en) 1981-11-03 2012-02-07 Personalized Media Communications, Llc Signal processing apparatus and methods
US9210370B1 (en) 1981-11-03 2015-12-08 Personalized Media Communications LLC Signal processing apparatus and methods
US8191091B1 (en) 1981-11-03 2012-05-29 Personalized Media Communications, Llc Signal processing apparatus and methods
US8395707B1 (en) 1981-11-03 2013-03-12 Personalized Media Communications LLC Signal processing apparatus and methods
US9038124B1 (en) 1981-11-03 2015-05-19 Personalized Media Communications, Llc Signal processing apparatus and methods
US8555310B1 (en) 1981-11-03 2013-10-08 Personalized Media Communications, Llc Signal processing apparatus and methods
US8558950B1 (en) 1981-11-03 2013-10-15 Personalized Media Communications LLC Signal processing apparatus and methods
US8559635B1 (en) 1981-11-03 2013-10-15 Personalized Media Communications, L.L.C. Signal processing apparatus and methods
US8566868B1 (en) 1981-11-03 2013-10-22 Personalized Media Communications, L.L.C. Signal processing apparatus and methods
US8572671B1 (en) 1981-11-03 2013-10-29 Personalized Media Communications LLC Signal processing apparatus and methods
US8584162B1 (en) 1981-11-03 2013-11-12 Personalized Media Communications LLC Signal processing apparatus and methods
US8587720B1 (en) 1981-11-03 2013-11-19 Personalized Media Communications LLC Signal processing apparatus and methods
US8601528B1 (en) 1981-11-03 2013-12-03 Personalized Media Communications, L.L.C. Signal processing apparatus and methods
US8607296B1 (en) 1981-11-03 2013-12-10 Personalized Media Communications LLC Signal processing apparatus and methods
US8613034B1 (en) 1981-11-03 2013-12-17 Personalized Media Communications, Llc Signal processing apparatus and methods
US8621547B1 (en) 1981-11-03 2013-12-31 Personalized Media Communications, Llc Signal processing apparatus and methods
US8635644B1 (en) 1981-11-03 2014-01-21 Personalized Media Communications LLC Signal processing apparatus and methods
US8640184B1 (en) 1981-11-03 2014-01-28 Personalized Media Communications, Llc Signal processing apparatus and methods
US8646001B1 (en) 1981-11-03 2014-02-04 Personalized Media Communications, Llc Signal processing apparatus and methods
US8675775B1 (en) 1981-11-03 2014-03-18 Personalized Media Communications, Llc Signal processing apparatus and methods
US8683539B1 (en) 1981-11-03 2014-03-25 Personalized Media Communications, Llc Signal processing apparatus and methods
US8713624B1 (en) 1981-11-03 2014-04-29 Personalized Media Communications LLC Signal processing apparatus and methods
US8711885B1 (en) 1981-11-03 2014-04-29 Personalized Media Communications LLC Signal processing apparatus and methods
US8739241B1 (en) 1981-11-03 2014-05-27 Personalized Media Communications LLC Signal processing apparatus and methods
US8752088B1 (en) 1981-11-03 2014-06-10 Personalized Media Communications LLC Signal processing apparatus and methods
US8804727B1 (en) 1981-11-03 2014-08-12 Personalized Media Communications, Llc Signal processing apparatus and methods
US8839293B1 (en) 1981-11-03 2014-09-16 Personalized Media Communications, Llc Signal processing apparatus and methods
US8843988B1 (en) 1981-11-03 2014-09-23 Personalized Media Communications, Llc Signal processing apparatus and methods
US8869229B1 (en) 1981-11-03 2014-10-21 Personalized Media Communications, Llc Signal processing apparatus and methods
US8869228B1 (en) 1981-11-03 2014-10-21 Personalized Media Communications, Llc Signal processing apparatus and methods
US8893177B1 (en) 1981-11-03 2014-11-18 {Personalized Media Communications, LLC Signal processing apparatus and methods
US8914825B1 (en) 1981-11-03 2014-12-16 Personalized Media Communications LLC Signal processing apparatus and methods
US8973034B1 (en) 1981-11-03 2015-03-03 Personalized Media Communications LLC Signal processing apparatus and methods
US4433211A (en) * 1981-11-04 1984-02-21 Technical Communications Corporation Privacy communication system employing time/frequency transformation
US4627074A (en) * 1982-02-26 1986-12-02 Siemens Aktiengesellschaft Method and arrangement for transmitting characters
US4591673A (en) * 1982-05-10 1986-05-27 Lee Lin Shan Frequency or time domain speech scrambling technique and system which does not require any frame synchronization
US4661980A (en) * 1982-06-25 1987-04-28 The United States Of America As Represented By The Secretary Of The Navy Intercept resistant data transmission system
US4602283A (en) * 1982-10-25 1986-07-22 Cselt - Centro Studi E Laboratori Telecomunicazioni S.P.A. System for spatially and temporally transposing data words arrayed in periodically recurring patterns
US4551580A (en) * 1982-11-22 1985-11-05 At&T Bell Laboratories Time-frequency scrambler
US4608456A (en) * 1983-05-27 1986-08-26 M/A-Com Linkabit, Inc. Digital audio scrambling system with error conditioning
US4638357A (en) * 1984-01-20 1987-01-20 Home Box Office, Inc. Audio scrambler
US7966640B1 (en) 1987-09-11 2011-06-21 Personalized Media Communications, Llc Signal processing apparatus and methods
US7958527B1 (en) 1987-09-11 2011-06-07 Personalized Media Communications, Llc Signal processing apparatus and methods
US5253296A (en) * 1991-11-26 1993-10-12 Communication Electronics System for resisting interception of information
EP1327937A4 (en) * 2000-09-20 2004-05-12 Yutaka Yasukura ELECTRONIC INFORMATION EDITING / RESTORING METHOD
US7231528B1 (en) * 2000-09-20 2007-06-12 Yutaka Yasukura Method of editing/restoring electronic information
US20040196971A1 (en) * 2001-08-07 2004-10-07 Sascha Disch Method and device for encrypting a discrete signal, and method and device for decrypting the same
US8520843B2 (en) * 2001-08-07 2013-08-27 Fraunhofer-Gesellscaft zur Foerderung der Angewandten Forschung E.V. Method and apparatus for encrypting a discrete signal, and method and apparatus for decrypting
US20110182421A1 (en) * 2005-09-26 2011-07-28 Ternarylogic Llc Encipherment of digital sequences by reversible transposition methods
US8180817B2 (en) 2005-09-26 2012-05-15 Temarylogic Llc Encipherment of digital sequences by reversible transposition methods

Also Published As

Publication number Publication date
NL167818C (nl) 1982-01-18
NL7109284A (enrdf_load_stackoverflow) 1972-01-11
ES392921A1 (es) 1973-11-01
DK133649C (enrdf_load_stackoverflow) 1976-11-08
SE363946B (enrdf_load_stackoverflow) 1974-02-04
CH518658A (de) 1972-01-31
GB1356970A (en) 1974-06-19
DE2046630A1 (de) 1972-01-20
BE769493A (fr) 1971-11-16
DK133649B (da) 1976-06-21
DE2046630B2 (de) 1974-08-08
FR2101561A5 (enrdf_load_stackoverflow) 1972-03-31
DE2046630C3 (de) 1975-03-20
JPS583426B1 (enrdf_load_stackoverflow) 1983-01-21
NL167818B (nl) 1981-08-17
AT327293B (de) 1976-01-26
ATA335471A (de) 1975-04-15

Similar Documents

Publication Publication Date Title
US3773977A (en) Method of enciphered information transmission by time-interchange of information elements
US3921151A (en) Apparatus for enciphering transmitted data by interchanging signal elements of the transmitted data without overlapping or omitting any elements within the transmitted signal train
US3970790A (en) Method and device for the coded transmission of messages
US3824467A (en) Privacy transmission system
US4211891A (en) Method for setting code text generators in ciphering devices
US3657699A (en) Multipath encoder-decoder arrangement
US4157454A (en) Method and system for machine enciphering and deciphering
CA1041236A (en) Common control framing detector
US4044380A (en) Encoder and constructed answer system for television
US4100374A (en) Uniform permutation privacy system
US3711645A (en) Method and apparatus for coding messages
EP0076862B1 (en) Error correction coding method
US3920894A (en) Pseudo-random parallel word generator
US3213201A (en) Multiplex transmission systems
NO910658D0 (no) Kryptografisk anordning for blokkvis omkodning basert paa psudotilfeldige ulineaere sekvenser.
US5938763A (en) System for transposing data from column order to row order
KR900000882A (ko) 시간 영역 신호를 인크립팅 및 디크립팅하는 방법 및 장치
KR860003574A (ko) Pcm 신호의 기록을 위한 방법 및 장치
NL8103494A (nl) Digitale signaalverwerkingsschakeling.
US3622701A (en) Character generation system
CA1054066A (en) Method and apparatus for the synchronization of a deciphering device functioning as receiver with an enciphering device functioning as transmitter
US3678198A (en) Circuit for generating a series of cipher pulses
US4181816A (en) Devices for combining random sequences, using one or more switching operations
JPS5926153B2 (ja) フアクシミリ受信方式
DE2310654C1 (de) Einrichtung zum bitweisen Ver- und Entschlüsseln digitaler Information