Computer simulation of the protection of a room from information leakage through a vibroacoustic channel

The quality of application of active means of information protection against leakage via vibroacoustic channel is traditionally assessed by the measured value of signal-to-noise ratio. In this case, measurements are taken at several control points to check the security, while the sample size is relatively small, and the measurement process is laborintensive. Based on the studies previously conducted by the authors of the article and modeling of acoustic wave propagation in the protected room, this paper proposes to calculate speech intelligibility at each point of the external enclosing surface along with the measured values of the signal-to-noise ratio on the surfaces of enclosing structures. A conclusion on the security of the room from information leakage via vibroacoustic channel is made by correlating the obtained values with the scale for assessing the quality of the intercepted speech message. The proposed method for assessing the security of a room is based on computer modeling of sound propagation. The interaction of acoustic air vibrations with a wall as one of the basic enclosing elements of the room is considered. The proposed approach is also applicable to the analysis of other structural elements of the room. The finite element model of the wall is implemented in the ANSYS program. The model provides for fixing a vibroacoustic emitter on the wall surface on one side of the wall, and a sound source at some distance from this surface. At each point on the opposite side of the wall surface, the signal-to-noise ratio is calculated. The signal level corresponds to the values of wall surface vibrations under the action of the sound source, and the noise level corresponds to the values of wall surface vibrations under the action of a vibroemitter attached to the wall from the inside. Based on experimental modeling, an assessment is made of the obtained values of speech intelligibility on the entire wall surface by comparing them with the scale for assessing the quality of intercepted speech messages adopted in security practice. The method proposed in the paper allows one to determine the least protected places in the studied premises by compiling maps of speech intelligibility distribution on the surfaces of walls and other enclosing structures. The study can find application in creating a system for protecting information from leakage through a vibroacoustic channel. Checking the security of enclosing structures using the proposed computer modeling method allows choosing a rational arrangement of protective equipment, their quantity, and also clarifying the security of premises assessed using traditional methods.