An efficient and secure VoIP communication system with chaotic mapping and message digest

As one of the most popular real-time services on the Internet, Voice over internet protocol (VoIP) has attracted researchers’ attention in the information security field for its characters of real-time and high flow. To protect data security, a new covert VoIP communications system was proposed in this study to realize secure communications by hiding secret information in VoIP streams. In the proposed algorithm, secret data were divided into blocks after being encrypted with a block cipher, and then each block of secret data was embedded into VoIP streaming packets randomly using a chaotic mapping. The symmetric key was distributed through an efficient and secure channel, and the message digest was implemented to protect the integrity of secret data. The experimental data were collected by comparing audio data between the sender and the receiver. The experimental results indicated that data embedding had little impact on the quality of speech. Besides, statistical analysis could not detect the secret data embedded in VoIP streams using the block cipher and random numbers generated from chaotic mapping. The proposed covert VoIP communications system not only achieved high quality of VoIP and prevented detection of statistical analysis, but also provided integrity for secret data.