IMPROVEMENT OF THE PASSIVE METHOD OF PROTECTING ACOUSTIC INFORMATION FROM LEAKAGE THROUGH AN ACOUSTIC-ELECTRICAL CHANNEL AT INFORMATION ACTIVITY FACILITIES

Abstract

The paper addresses the problem of protecting speech information from leakage through an acousto-electric channel at information activity facilities under conditions of rapid development of technical reconnaissance systems. A mathematical apparatus is presented that allows analysis of the dependencies between parameters affecting diffuse scattering from enclosing structures, particularly glass surfaces that can act as reflecting elements for laser acoustic reconnaissance systems (LARS). A formalized model of the acousto-electric information leakage channel based on an energy criterion is developed, taking into account the key physical characteristics of the receiver of a laser acoustic reconnaissance system, the signal propagation environment, and the properties of the reflecting surface. The process of transformation of the received optical signal at the input of the LARS receiver is modeled, including the influence of optical, geometric, and structural parameters of the glass surface. Particular attention is paid to the mechanisms of specular and diffuse reflection of laser radiation and their influence on the possibility of extracting speech information by an attacker. Based on the obtained results, approaches to improving both passive and active methods of protecting acoustic information are proposed. Using the synthesis method, recommendations are formulated for obtaining initial parameters for manufacturing glass-ceramic materials (sitall). Unlike conventional glass, these materials have a controlled granular and homogeneous microcrystalline structure capable of forming a surface roughness comparable to the wavelength of probing laser radiation. Such a structure ensures effective diffuse scattering of the incident laser beam and significantly reduces the power of the reflected signal received by the reconnaissance system.

The proposed approach allows a substantial reduction in the maximum operational range of laser acoustic reconnaissance systems and increases the resistance of protected facilities to remote speech interception. The obtained results can be used in the design of window structures and other enclosing elements of information activity facilities to improve passive protection of acoustic information without the need for additional energy consumption or complex active countermeasures.