Voice pattern hiding for VoIP communications

In this paper, we address issues related to traffic analysis attacks and the corresponding countermeasures in Voice over IP (VoIP) traffic. VoIP is widely used in today's communication, it converts analog voice signals into digital data packets and supports real-time, two-way transmission of conversations using Internet Protocol. We focus on a particular class of traffic analysis attack, timing-based correlation attacks, by which an adversary attempt to analyze packet inter-arrival time of a user and correlate the output traffic with the traffic in their database. Correlation method that is used in this type of attack, namely Dynamic Time Warping(DTW) based Correlation. Based on our threat model and known strategies in existing VoIP communication, we develop methods that can effectively counter the timing-based correlation attacks. The empirical results provided showed the effectiveness of the proposed scheme in term of countering timing-based correlation attacks.