Speech encryption using hybrid-hyper chaotic system and binary masking technique

P. Sathiyamurthi

doi:10.1007/s11042-021-11757-4

2022-01-10

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P. Sathiyamurthi *

S. Ramakrishnan

DOI：10.1007/s11042-021-11757-4

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摘要

En 中文

In this paper, a novel speech encryption algorithm based on hybrid-hyper chaotic system has presented. Instead of using normal chaotic system a hybrid-hyper chaotic system has used for improving the security level of speech communication models. Hyper-chaotic system is highly complex and dynamic system than normal chaotic system where it has more than one positive Lyapunov exponents. Hybrid chaotic system has designed by a disturbed discrete system by another one discrete system. In this algorithm, the input speech signal has compressed by Discrete Cosine Transform (DCT) to reduce the residual intelligibility. The compressed speech signal has permuted by hybrid chaotic system, which has designed using Zaslavsky and Zigzag maps. For substitution process, a reference speech signal has generated by Hidden Markov Model (HMM) speech synthesizer and permuted by using hyper-chaotic system. Masking of encryption signal has done by a masking sequence, which has obtained from the hyper-chaotic system. Our proposed work provides high security for the audio and speech signal over an insecure public network than other traditional speech encryption algorithms based on normal chaotic systems. The betterment of proposed algorithm is proven using the following metrics: key space analysis, key sensitivity analysis, information entropy measure, correlation coefficient analysis, Signal to Noise Ratio (SNR) analysis, subjective evaluation of speech quality, Perceptual Evaluation of Speech Quality (PESQ) analysis, NSCR (Number of Samples Changing Rate) and UACI (Unified Averaged Changed Intensity) analysis have carried out from cryptographic point of view and presented in this paper. The results proof that the proposed speech encryption algorithm ensures appreciable security system with robust encryption and decryption quality.

Keyword:

Hybrid chaos

Hyper chaotic system

Zaslavsky map

Zigzag map

Permutation

Substitution

Binary masking