A new 6D conservative hyperchaotic system and its application in speech encryption

Abstract Conservative chaotic systems lack attractors, providing significantly stronger resistance to reconstruction attacks than dissipative systems and establishing themselves as a research focus in secure communications. This paper proposes a novel 6D hyperchaotic system that simultaneously satisfies both Hamiltonian energy conservation and phase volume conservation. Dynamical analysis, along with spectral entropy and C 0 complexity calculations, confirms the system’s excellent hyperchaotic characteristics, while NIST test verifies the high randomness of its pseudorandom sequences. Based on this system, a new FFT-based speech encryption algorithm is presented. By separating the complex frequency domain signal into real and imaginary parts, the algorithm more fully utilizes the spectral features of speech, thereby enhancing its adaptability. Performance analysis indicates that the algorithm ensures secure speech transmission while maintaining speech quality. Finally, the physical realizability of the chaotic system is verified through circuit simulation and a DSP hardware platform.