this paper an algorithm for speech encryption based on three dimension chaotic maps is proposed. The proposed algorithm consists of three main units: generation of keys, samples substitution and samples permutation process. In order to maximize the benefits of the substitution process, it is performed in two stages with cipher feedback, for the system. Moreover bit-level permutation for sample is introduced as substitution mechanism in the permutation stage. The Lorenz and Rossler chaotic system are employed as generation of keystream used for substitution and permutation process respectively. From the experimental results, it is concluded that the proposed algorithm has the advantages of very low residual intelligibility, key sensitivity and high quality recovered signal, and moreover the proposed algorithm can resist known- plaintext attacks and supports large key space make brute-force attacks infeasible.

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Lorenz and Rossler Chaotic System for Speech Signal Encryption

A lightweight AES algorithm implementation for encrypting voice messages using field programmable gate arrays

Speech encryption is used to convert clear speech into unintelligible signal in order to avoid eavesdropping for this purpose, cryptographic techniques and chaotic maps can be applicable. In this paper, a speech cryptosystem based on substitution and permutation is presented. The speech signal has been processed using different discrete transforms. Then the system has been developed using different chaotic maps like 2D Logistic map, Henon map, and Baker. Different objective quality measures for speech have been used to measure the quality of encrypted and decrypted speech signals.

Speech encryption using two dimensional chaotic maps

In this paper, the speech signal is encrypted using multiple chaotic maps and cryptographic protocols. The input signal is fragmented and scrambled into four segments using cubic map. In order to make the signal invulnerable against attacks, scrambled signal is processed through various one-dimensional chaotic maps like cubic, logistic, skew-tent, and quadratic map. All chaotic maps are employed to provide an encryption at transmitter side; however, reversal of the same is carried out at other end. To protect the various parameters of all chaotic techniques, blowfish algorithm is employed with the private key. On top of that, additional layer of security is provided through hashing algorithm for authentication of shared data and the blowfish key of system between two ends. The computed message digest of secure hash algorithm should be same for successful communication, which authenticates and verify the parameters of chaotic maps. Furthermore, several tests have been performed on 8 KHz secured speech signal such as signal-to-noise ratio, power-spectral density, peak signal-to-noise ratio, and correlation test in order to check the efficiency of proposed system. The various statistical tests and analysis of adversary model validates the encryption model and embraces stronger security, thus making it as invulnerable to the attacks of intruder. The result promises that presented technique is extremely secure, provides end-to-end encryption and can be utilized in a real time speech communication.

Chaos-based joint speech encryption scheme using SHA-1

The developments in technology have made us utilizing speech as a biometric to authenticate persons. In this paper, speech encryption and decryption algorithm are presented for enhancing the security in speech-based person authentication systems. The implementation of the authentication system contains the feature extraction, modeling techniques and testing procedures for authenticating the person. Firstly, the Mel frequency cepstral coefficient (MFCC) features are extracted from the training speech utterances and models are developed for each speaker. The speech encryption system encrypts the test speech utterances. Multiple chaotic mapping techniques and Deoxyribonucleic acid (DNA) addition based speech cryptosystem is developed to secure test speech against attacks. The speech encryption system deals with sampled test speech signal given as input, which is subjected to intra level and inter level bit substitution. These resultant samples are encoded into the DNA sequence denoted by P(n). The DNA sequence P(n) and DNA sequences {A(n), B(n), C(n), D(n)} obtained using different techniques based on chaos, such as tent mapping, henon mapping, sine mapping, and logistic mapping and summed up together using DNA addition operation. Finally, the encrypted test speech is obtained using DNA decoding. The speaker authentication system in the receiving side decrypts the encrypted signal and identifies the speakers from the decrypted speech. The correlation coefficient test, Signal to noise ratio test, Peak Signal to Noise Ratio test, key sensitivity test, NSCR and UACI test, key space analysis, and histogram analysis are the techniques used as metrics to prove the efficiency of the proposed cryptosystem. Overall individual accuracy is 97% for the text dependent person authentication with the original test speech set and decrypted test speech set. Overall individual accuracy is 66% for the text independent person authentication with the original test speech set and decrypted test speech set. In our work, the speech utterances are taken from AVSpoof database for authenticating 44 speakers. Our work highlights the efficiency of the encryption system, to provide security for test speech and person authentication using speech as a biometric.

A robust cryptosystem to enhance the security in speech based person authentication

Encryption of speech signal with multiple secret keys

In this paper, we proposed an encryption system for speech signals based on circular shifts in row and column. This cryptosystem uses three secret keys. The original key is generated, randomly, using a pseudo noise sequence generator, and the two other keys are obtained by using the main key. The encryption system also uses Discrete Cosine Transform (DCT) or the Discrete Sine Transform (DST) to remove the signal intelligibility. Moreover, the performance of the proposed algorithm is also estimated by correlation coefficient quantity.

Fatiha Merazka

Papers

Encryption of speech signal with multiple secret keys

Encryption of speech signal with multiple secret keys.