RU2674751C1 - Method of detection of acoustic optic fiber channel of speech information leakage through optical fibers of cable lines and protection from leakage of speech information through optical fibers - Google Patents

Abstract

FIELD: communication equipment.

SUBSTANCE: invention relates to communication technology and can be used to ensure information security of negotiations in designated areas from the threat of leakage of acoustic (voice) information through fiber-optic communications. In the method of detecting the acousto-optic fiber channel, the leakage of speech information through optical fibers of cable lines and the protection against leakage of voice information through optical fibers in the optical fiber register all light fluxes and analyze the possibility of eavesdropping, herewith, one of the signs of leakage of acoustic (speech) information is the presence in the optical radiation propagating through the optical fiber of copies of signals with a delay of more than 50 mcs, and upon detection of copies, they are removed.

EFFECT: technical result is to increase the protect confidential voice information.

1 cl, 1 dwg

Description

The invention relates to the field of ensuring information security of negotiations in dedicated rooms from threats of leakage of acoustic (speech) information through fiber-optic communications by monitoring optical flows in standard communication lines and identifying possible modulation of their acoustic fields. The invention can be used in systems for protecting confidential voice information.

Known methods for fixing the presence of optical radiation in the fiber. For example, Fujikura FID-20R / 21R (Japan, http://www.fujikura.ru/) implemented in the determinant of the presence of an optical signal in a fiber, which allows one to determine the presence and direction of propagation of an optical signal in a fiber coated with 250 μm, 900 μm, as well as in standard optical cords up to 3 mm thick. However, it does not allow isolating the signals transmitted during unauthorized connection to the fiber.

A known method [1] of detecting an acousto-optical fiber channel for the leak of confidential speech information in a fiber-optic channel for transmitting information, which consists in the fact that all the light fluxes are recorded in the fiber-optic channel for transmitting information and an analysis of the possibility of eavesdropping is performed. The danger of leakage of acoustic (speech) information is determined by the following criteria:

1) an abnormal light flux is detected in the information transmission channel;

2) the standard luminous flux has acoustic modulation in one of the parameters of optical radiation (amplitude, phase, polarization, frequency) and / or simultaneously in several parameters;

3) abnormal light fluxes separated by the optical spectrum have acoustic modulation at a given optical wavelength in one of the parameters of the optical radiation (amplitude, phase, polarization, frequency) and / or simultaneously in several parameters.

Fulfillment of at least one of these conditions is sufficient to form a channel for leakage of acoustic (speech) information and can be used to assess information security threats. The disadvantages of this method include the fact that analysis is not provided for one of the main signs of the presence of an acousto-optical fiber channel for leakage of speech information, namely the presence in the signal of copies propagating with a delay of more than 50 μs [2]. In addition, leakage protection is not provided in case of detection of an acoustic-optical fiber channel for speech information leakage.

The essence of the alleged invention is the expansion of the scope.

This essence is achieved by the fact that, according to the method for detecting an acoustic-optical fiber channel for leakage of speech information through optical fibers of cable lines and protecting against leakage of speech information through optical fibers in an optical fiber, all light fluxes are recorded and analysis of the possibility of eavesdropping is performed, one of the signs of acoustic leakage ( speech) information is the presence of copies of signals with a delay of more than 50 μs in the optical radiation propagating through the optical fiber, and when copies are detected delete.

Figure 1 presents the structural diagram of a device for implementing the proposed method.

The device comprises a fiber optic cable 1 with an optical fiber 2, an input / output device 3, an analysis and conversion unit for optical signals 4.

The method is as follows. The optical radiation propagating in both directions along the optical fiber 2 of the optical fiber cable 1 through the input / output device 3 is output from the optical fiber 2 to the optical signal analysis and conversion unit 4, in which, among other things, the transmitted optical signals are analyzed for copies coming from a delay of more than 50 μs, and if such copies are detected, they are deleted.

In contrast to the known method, which is the prototype, in the proposed method, when analyzing light fluxes for the possibility of eavesdropping, such a feature as the presence of copies of signals arriving with a delay of more than 50 μs is taken into account, and when such copies are detected, they are deleted, which allows to increase the capabilities of the method by detection of leakage channels in comparison with the prototype and protect speech information from leaks of this type. As a result, the scope of the proposed method is expanded in comparison with the prototype.

LITERATURE

1. RU 2428798.

2. US 8000609.

Claims (1)

A method for detecting an acoustic-optical fiber channel for leakage of speech information through optical fibers of cable lines and protection against leakage of speech information through optical fibers, according to which all light fluxes are recorded in an optical fiber and analysis of the possibility of eavesdropping is performed, while one of the signs of leakage of acoustic information is the presence of optical fiber optical radiation copies of signals with a delay of more than 50 μs, and when copies are detected they are removed.

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