Ways to improve the efficiency of methods and means of counteracting unauthorized speech recording and their comparative analysis

The features of using ultrasonic, electromagnetic and acoustic methods to counteract unauthorized recording of speech on sound recording devices are considered. The advantages and unused possibilities of the methods are noted. Ways to increase the effectiveness of the ultrasonic method of counteraction consist in using the two-frequency ultrasonic method, in positioning the device for emitting ultrasonic vibrations no more than two meters from the target, in using high-intensity ultrasonic vibrations, in using the ultrasonic method together with the acoustic method, and others. Ways to increase the effectiveness of the electromagnetic method consist in using amplitude-pulse modulation of the interference signal, narrowly directed antennas, a device with a maximum allowable power, and others; Ways to increase the effectiveness of the acoustic method consist in creating speech-like interference from the speech of the interlocutor (synchronized with speech pauses), reducing the distance between the source of interference radiation and the source of speech in relation to the distance between the interlocutors due to organizational protection measures. (adapted acoustic method). The most promising is the adapted acoustic method having the greatest potential for guaranteed countermeasures, subject to the requirements for its optimal use. Analyzing the results of the experiment, we conclude that the adapted acoustic method is the most effective. The effectiveness of the method confirms the suppression range from 1.8 m to 3.5 m depending on the device, for comparison, in the ultrasonic experiment, one of the indicators was 0.9 m, and in the electromagnetic experiment, even 0 m. The formation of interference through the acoustic channel is higher the described method ensures the universality of the proposed method to the type of device for suppressing unauthorized speech recording, regardless of the underlying method – electromagnetic, ultrasonic or acoustic.