A Novel Covert Timing Channel Based on RTP/RTCP

A covert timing channel utilizes temporal features to transfer secret messages. This paper proposes a framework of network covert timing channels based on information theory to measure their capacity and efficiency. Different from many former channels constructed upon a single transport layer protocol, the paper designs and implements a novel covert timing channel based on RTP and RTCP which both belong to the application layer. The channel utilizes Run Length Code and Multi-Zero Code to improve imperceptibility and robustness. The evaluation and test results show that the channel is superior in covert communication for it is quite robust against jitter and packet loss with high imperceptibility.