Chaos-based joint speech encryption scheme using SHA-1

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.