EP0136681B1 - Procédé de transmission chiffrée d'informations - Google Patents

Procédé de transmission chiffrée d'informations Download PDF

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Publication number
EP0136681B1
EP0136681B1 EP84111665A EP84111665A EP0136681B1 EP 0136681 B1 EP0136681 B1 EP 0136681B1 EP 84111665 A EP84111665 A EP 84111665A EP 84111665 A EP84111665 A EP 84111665A EP 0136681 B1 EP0136681 B1 EP 0136681B1
Authority
EP
European Patent Office
Prior art keywords
code
transmission
transmission side
transmitter
subscriber
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
Application number
EP84111665A
Other languages
German (de)
English (en)
Other versions
EP0136681A3 (fr
EP0136681A2 (fr
Inventor
Ludwig Dipl.-Ing. Hofmann
Klaus Stadler
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.)
Siemens AG
Original Assignee
Siemens 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 Siemens AG filed Critical Siemens AG
Priority to AT84111665T priority Critical patent/ATE35754T1/de
Publication of EP0136681A2 publication Critical patent/EP0136681A2/fr
Publication of EP0136681A3 publication Critical patent/EP0136681A3/xx
Application granted granted Critical
Publication of EP0136681B1 publication Critical patent/EP0136681B1/fr
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K1/00—Secret communication

Definitions

  • the invention relates to a method for encrypted message transmission in transmission systems with fixed and / or mobile subscriber devices (terminals), for example in telephone, car phone or radio networks, in which in the terminal one transmitter side a transmitter for an individual subscriber key and in An evaluator, which is designed as a central station and is only accessible on the official side, is arranged and in which, in a first method step, the subscriber number is transmitted from the transmission side containing the encoder to the other transmission side, in which the subscriber key is determined and the recipient is set according to the key and in the thereafter in a second method step, the transmission path for transmitting the encrypted useful signal to the transmitting part is switched through in the terminal device containing the transmitter.
  • a method for encrypted message transmission of the type described in the preamble of claim 1 is known from DE-B-2 659 622.
  • This describes a radio telephony system for a large number of subscribers, in which the messages are transmitted through an encryption or concealment device, in particular by means of digital signals, e.g. with a specific individual sequence, i.e. with a specific subscriber-specific key.
  • the participant number itself or a special code is also stored.
  • There is a functional connection between the subscriber number or the code and the individual key setting which is only known to the higher-level exchange (radio gateway).
  • This individual key is calculated in the exchange and the encryption or concealment device is programmed. Then the encrypted transmission to the exchange and from there the transmission of the messages is carried out, if necessary after conversion into the key of the conversation partner.
  • a ciphering / deciphering system is known with a ciphering part with means for converting plain texts into a ciphertext and a deciphering part with means for converting the ciphertext back into clear data.
  • the encryption part contains an encryption generator, the initial state and / or structure of which is determined at least by a first secret key, and a first memory with a number of different first keys.
  • the decryption part contains a decryption generator constructed in the same way as the encryption generator and a second memory with the same first keys as in the first memory.
  • Encryption and decryption parts also contain key loading means, in order to select a first key from the first memory when the system is reinitialized, to load it into the encryption generator, to transfer the memory address of the selected first key to the decryption part, and there, based on the transmitted memory address, to transfer the same first key from the read out the second memory and load it into the decryption generator.
  • the key loading means are controlled by a random stage located in the encryption part, which forms a random selection address for the first key contained in the first and second memory and to be reloaded during the reinitialization each time the system is reinitialized.
  • the invention has for its object to provide a method for encrypted message transmission, which can be used in a variety of ways in networks of message transmission and is relatively difficult to listen to automatically.
  • This object is achieved according to the invention by a hierarchical structure in such a way that several end devices are connected to a center in the networks and the code signaling from the end device to the central device takes place in a non-system-compatible sequence, and further in that in the first method step of the Transmitter-containing transmission side, the set code is transmitted to the other transmission side designed as a central station.
  • the transmitted code forms a pointer in a code table.
  • an encryption system for a mobile telephone system is shown in the block diagram.
  • a mobile device and a base station part are provided which are in radio communication with one another via a radio field FF.
  • the mobile device contains a handset 1, an LF amplifier and voice scrambler connected to it, which are arranged in box 2, and a radio part 3 connected downstream thereof, which is connected on the output side to an antenna A1.
  • LF amplifier and voice scrambler 2 are connected to one another via a reception line and a transmission line for the low frequency.
  • a changeover switch S is inserted into the transmission line and is controlled by a code transmitter 4.
  • the code transmitter 4 is also connected to the LF amplifier and voice scrambler 2 and effects the code setting therein as well as with a signaling unit 5 which is connected on the output side to the one changeover contact of the changeover switch S and via this changeover switch S to the transmission path the mobile device can be switched on.
  • the base station part contains a radio part 6 which is connected to an antenna A2 and which is connected to a voice scrambler and an NF adaptation, which are arranged in box 7.
  • voice scrambler and LF adaptation are carried out for the transmission of the low frequency LF to a transfer device ULE, not shown in the figure, which forms a connection device between the base station part (radio concentrator) and the telephone network with the switching offices.
  • Radio part 6 and voice scrambler and LF adaptation 7 are connected to one another via a reception line and a transmission line for the low frequency, a connection to a code evaluator and a synchronization device, which are contained in box 8, being made by the reception line. On the output side, this is connected to the voice scrambler and NF adaptation 7 for code setting.
  • the radio parts 3 and 6 in the two terminals can consist of commercially available transceivers which are interconnected in the manner shown with the respective concealment devices.
  • a dynamic obfuscation mode is used here using the 4-band swap, which, for. B. with the aid of a random generator from the mobile subscriber with the transmitter to the concealment device of the radio concentrator with the receiver.
  • this receiver in the gateway and / or in the exchanges or also at the B subscriber.
  • the radio path is encrypted in such a way that the base station part is first synchronized to the mobile device from the signaling unit 5 via the changeover switch S controlled by the code transmitter 4.
  • the dynamic transmitter then transmits the dynamic obfuscation mode from the mobile device to the base station part, and via its code evaluator and synchronization device 8, the code is set in the voice scrambler and the NF adaptation 7, so that the transmitted, veiled signal in the receiver of the base station part is correct is recognized.
  • the method according to the invention is based on the principle that terminals only generate a transmission code, but cannot evaluate it.
  • the evaluators are unable to generate the code and, moreover, they are only available in limited numbers.
  • a strictly hierarchical structure is provided here. This means that in the relevant networks, several terminal devices are always connected to a central station on the base station side, which can only be entered and serviced by authorized personnel.
  • the key transmitted from the terminal, in this case the mobile device, to a central key device merely forms a pointer in a code table. In this way, security against eavesdropping can be achieved in systems of the same structure by changing the code table.
  • the advantage of the method according to the invention is that in addition to a high number of obfuscation modes, the use of a normal radio transceiver belonging to this corresponding mobile radio system means that the radio paths cannot be intercepted, since this radio transceiver can only be used with one transmitter and is not equipped with a receiver, the concealment receiver cannot be released for public transport due to a corresponding delivery restriction and this system, although the radio subscriber devices can be sold on the open market without restriction, contains a high degree of concealment security.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Reverberation, Karaoke And Other Acoustics (AREA)
  • Telephonic Communication Services (AREA)

Claims (2)

1. Procédé de transmission chiffrée d'informations dans des systèmes de transmission comportant des postes d'abonnés (terminaux) fixes et/ou mobiles, par exemple dans des réseaux téléphoniques, radiotéléphoniques ou radio, dans lequel il est prévu, dans le terminal d'un des côtés de la transmission, un générateur (4) destiné à un code propre au terminal, et dans l'autre côté de la transmission qui est réalisé comme poste central, et qui est uniquement accessible côté central, un analyseur (8), et dans lequel, dans un premier stade du procédé, le numéro de l'abonné est transmis du côté de la transmission comprenant le générateur (4), à l'autre côté de la transmission, dans lequel le code d'abonné est déterminé et le récepteur est réglé en fonction du code, et dans lequel ensuite, et dans un second stade du procédé, dans le terminal comportant le générateur (4), la voie de transmission est établie pour la transmission du signal utile chiffré à la partie émission, caractérisé par une structure hiérarchique d'un type tel que dans les réseaux, plusieurs terminaux sont chaque fois reliés à un central, et la signalisation codée du terminal à l'appareil central a lieu suivant un processus non compatible à un système, et de plus par le fait que dans le premier stade du procédé, le code réglé est transmis du côté de la transmission contenant le générateur (4), à l'autre côté de la transmission réalisé comme poste central.
2. Procédé selon la revendication 1, caractérisé en ce que le code transmis constitue un indicateur dans une table de codes.
EP84111665A 1983-09-30 1984-09-28 Procédé de transmission chiffrée d'informations Expired EP0136681B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84111665T ATE35754T1 (de) 1983-09-30 1984-09-28 Verfahren zur verschluesselten nachrichtenuebertragung.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19833335672 DE3335672A1 (de) 1983-09-30 1983-09-30 Verfahren zur verschluesselten nachrichtenuebertragung
DE3335672 1983-09-30

Publications (3)

Publication Number Publication Date
EP0136681A2 EP0136681A2 (fr) 1985-04-10
EP0136681A3 EP0136681A3 (fr) 1985-06-05
EP0136681B1 true EP0136681B1 (fr) 1988-07-13

Family

ID=6210671

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84111665A Expired EP0136681B1 (fr) 1983-09-30 1984-09-28 Procédé de transmission chiffrée d'informations

Country Status (3)

Country Link
EP (1) EP0136681B1 (fr)
AT (1) ATE35754T1 (fr)
DE (2) DE3335672A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT393339B (de) * 1987-10-21 1991-09-25 Siemens Ag Oesterreich Vorrichtung zur verschleierten uebertragung analoger signale
KR20030093197A (ko) * 2001-01-16 2003-12-06 텔레폰악티에볼라겟엘엠에릭슨(펍) 압축을 사용하는 난수 발생기
ATE348359T1 (de) * 2001-01-16 2007-01-15 Ericsson Telefon Ab L M Zufallszahlengenerator basierend auf komprimierung

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2722700A1 (de) * 1973-07-06 1978-11-30 Licentia Gmbh Schaltungsanordnung zum uebertragen von nachrichtensignalen
DE2659622C2 (de) * 1976-12-30 1979-01-04 Siemens Ag, 1000 Berlin Und 8000 Muenchen Funktelefoniesystem
US4369434A (en) * 1979-12-20 1983-01-18 Gretag Aktiengesellschaft Enciphering/deciphering system

Also Published As

Publication number Publication date
ATE35754T1 (de) 1988-07-15
EP0136681A3 (fr) 1985-06-05
EP0136681A2 (fr) 1985-04-10
DE3335672A1 (de) 1985-04-04
DE3472742D1 (en) 1988-08-18

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