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1. WO1990014722 - SYSTEM AND METHOD FOR COMMUNICATIONS SECURITY PROTECTION

Publication Number WO/1990/014722
Publication Date 29.11.1990
International Application No. PCT/US1990/002882
International Filing Date 14.05.1990
Chapter 2 Demand Filed 03.12.1990
IPC
H04K 1/02 2006.01
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
KSECRET COMMUNICATION; JAMMING OF COMMUNICATION
1Secret communication
02by adding a second signal to make the desired signal unintelligible
H04K 3/00 2006.01
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
KSECRET COMMUNICATION; JAMMING OF COMMUNICATION
3Jamming of communication; Counter-measures
CPC
H04K 1/02
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
KSECRET COMMUNICATION; JAMMING OF COMMUNICATION
1Secret communication
02by adding a second signal to make the desired signal unintelligible
H04K 2203/16
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
KSECRET COMMUNICATION; JAMMING OF COMMUNICATION
2203Jamming of communication; Countermeasures
10Jamming or countermeasure used for a particular application
16for telephony
H04K 3/28
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
KSECRET COMMUNICATION; JAMMING OF COMMUNICATION
3Jamming of communication; Counter-measures
20Countermeasures against jamming
28with jamming and anti-jamming mechanisms both included in a same device or system, e.g. wherein anti-jamming includes prevention of undesired self-jamming resulting from jamming
H04K 3/42
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
KSECRET COMMUNICATION; JAMMING OF COMMUNICATION
3Jamming of communication; Counter-measures
40Jamming having variable characteristics
42characterized by the control of the jamming frequency or wavelength
H04K 3/43
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
KSECRET COMMUNICATION; JAMMING OF COMMUNICATION
3Jamming of communication; Counter-measures
40Jamming having variable characteristics
43characterized by the control of the jamming power, signal-to-noise ratio or geographic coverage area
H04K 3/825
HELECTRICITY
04ELECTRIC COMMUNICATION TECHNIQUE
KSECRET COMMUNICATION; JAMMING OF COMMUNICATION
3Jamming of communication; Counter-measures
80Jamming or countermeasure characterized by its function
82related to preventing surveillance, interception or detection
825by jamming
Applicants
  • SYNTELLECT INC. [US]/[US]
Inventors
  • SALTWICK, John, M.
  • SPARKS, William
  • SCARINCI, Dean
  • GATES, Geoffrey, W.
Agents
  • KADEN, Jeffrey, M.
Priority Data
354,26119.05.1989US
Publication Language English (EN)
Filing Language English (EN)
Designated States
Title
(EN) SYSTEM AND METHOD FOR COMMUNICATIONS SECURITY PROTECTION
(FR) SYSTEME ET PROCEDE DE PROTECTION DE SECURITE POUR COMMUNICATIONS
Abstract
(EN)
A system and method are disclosed for preventing intelligible interception of information signals transmitted over a two-direction line (26). A masking signal is applied through a hybrid circuit (24) at the receiving end of the line (28), and this masking signal, which appears on the line together with the information signal, prevents intelligible decoding. The masking signal includes a series of frequencies which are sequentially applied. Only at the receiving end of the line, where the hybrid circuit (24) attenuates the masking signal which it receives at its receive port, can intelligible decoding take place. The amplitude of the information signals is sensed (34) at the receiving end and the amplitude of the masking signals on the line is adjusted (44) to be great enough to provide security, by confusing an eavesdropping detector, yet small enough at the receiving end so that the receiving detector is not confused.
(FR)
L'invention concerne un système et un procédé permettant d'empêcher l'interception intelligible de signaux d'information transmis sur une ligne à double sens (26). On applique un signal de masquage par l'intermédiaire d'un circuit hybride (24) au niveau de l'extrémité de réception de la ligne (28), et ce signal de masquage, lequel apparaît sur la ligne avec le signal d'information, empêche le décodage intelligible. Ledit signal de masquage comprend une série de fréquences, lesquelles sont appliquées de manière séquentielle. Le décodage intelligible ne peut avoir lieu qu'à l'extrémité de réception de la ligne, où le circuit hybride (24) atténue le signal de masquage qu'il reçoit au niveau de sa porte de réception. L'amplitude des signaux d'information est détectée (34) au niveau de l'extrémité de réception, et l'amplitude des signaux de masquage transmis sur la ligne est réglée (44) pour être suffisamment grande afin d'assurer une sécurité, par brouillage d'un détecteur d'écoute clandestine, mais pour être suffisamment faible au niveau de l'extrémité de réception de sorte que le détecteur de réception ne soit pas brouillé.
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