Application of Fast Fourier Transform to the Speech Signals Scrambling

Abstract

The article is devoted to the closure of speech signals by implementing a fast Fourier transform in a bandpass scrambler. The most radical measure to prevent the interception of speech signals is the use of cryptographic security methods. The first technical security systems began to be developed immediately after the invention of the telephone. The main goal when developing speech transmission systems is to preserve those characteristics that are most important for the listener to perceive. Communication security in the transmission of voice messages is based on the use of a large number of different methods of blocking signals that change the characteristics of speech in such a way that it becomes illegible and unrecognizable to attackers who listen to or intercept the closed voice message. The choice of closure methods depends on the specific application and the technical characteristics of the transmission channel. That is, technical channels of information leakage are a source of information for technical intelligence, which extracts information using technical means. Therefore, the problem of protecting information from technical intelligence is of particular relevance. The object of the study is the transmission of voice messages. The subject of the research is real-time speech closing systems. The purpose of the paper is to use fast Fourier transform to close speech signals in a bandpass scrambler. To do this, it is necessary to assess the capabilities of technical intelligence to intercept information of limited distribution; analyze types of speech signal closing systems.
 The paper presents a block diagram of a combined scrambler, an algorithm for rearranging input signal values using the fast Fourier transform, and hashing functions that are used to obtain a speech signal from a combined scrambler. It has been determined that "through-window" scramblers are the most reliable, and for greater levels of closure, combination scramblers should be used. The task set for further development of the topic is the development of a software application for the operation of streaming data encryption methods in real time.