Multi-Level Speech Encryption Using Chaotic Maps

With the rapid improvement of digital communications and multimedia applications, protecting digital data, such as images, speech, and videos, has become a crucial challenge. Chaotic encryption is an important, essential, and effective encryption method for securing speech signals as the most natural communication mode. Encrypted signals using chaotic systems are noisy signals that increase the level of confusion during signal transmission over a channel. In this study, in addition to reviewing recent works on speech encryption, a novel approach for chaos-based speech encryption based on signal multi-level partitioning is proposed. Signal multi-level partitioning allows for the use of multiple mappings, which increases the number of initial parameter values. Consequently, we will have a larger key space, which will lead to increased security against various attacks. The speech signal encrypted using the approach proposed in this study is noisier than the results of previous research studies, and because of the significantly larger key space (more than three times that of previous studies), it provides higher security against attacks. It is worth mentioning that, despite the higher efficiency of the proposed encryption algorithm, its computational complexity does not affect the speed of the algorithm, and speech signal reconstruction during decryption is performed with high efficiency.