Digital Chaotic Scrambling of Voice Based on Duffing Map

With the significant development in communication systems especially in the public channels through which our information travels, there are more increasing in the channels problems. The information security is the important one that should be enhanced. This paper presents a chaos-based speech scrambling system. Chaotic maps have been successfully used for large-scale data encryption such as image, audio and video data, due to their good properties such as pseudo-randomness, sensitivity to changes in initial conditions and system parameters and a periodicity. In this paper a security model based on chaotic system has been designed to be used to encrypt voice signal, chaotic duffing map used for digital Scrambling, each samples of the speech are divided into 8 bits. The simulation results show that the Cpestral Distance Measure (CD) in the proposed system is increased by (4.559) by comparing with the time domain scrambling which is about four times that gives from the analog scrambling. In addition, dlpc increased to (4.428) as comparing with time domain. The key space in this proposed is 11.8336 ∗ 10 × range of parameters.