Security Enhancement on VoIP using Chaotic Cryptography

Recently, voice over Internet protocol (VoIP) becomes popular as it allows people to make their phone calls using Internet connection instead of the traditional telephone network. However, Internet itself doesn´t provide any security measure and there is no guarantee that the audio streams transmitted over it have not been intercepted in between. In (Guo, J-I, et al.), the authors proposed a chaos-based encryption technique called hierarchical data security protection (HDSP) for VoIP. Nevertheless, it was found in ( Li, C, et al.) that HDSP is vulnerable to some sort of attacks and is not suggested to be used in secure applications. In this paper, an encryption algorithm for VoIP is developed. It is based on the chaotic cryptographic method proposed in (Wong, KW, et al.) and its security is carefully evaluated. We have successfully implemented the proposed method in a VoIP system using H.323 standard. The simulation results show that this encryption scheme can provide secure audio encryption