A Detection-Resistant Covert Timing Channel Based on Geometric Huffman Coding

Abstract

Network covert timing channel is a communication mechanism that transfers secret messages by modulating the timing characteristics of network traffic. It is targeted for secret information transmission on networks which can ensure security and confidentiality. However, most proposed covert timing channels can be detected by several detection methods such as regularity testing, distribution shape testing, entropy-based testing and recent machine learning based methods. In this paper, we design and implement a novel covert timing channel by leveraging Geometric Huffman Coding (GHC) to realize covert and overt channel matching. In network experiments and simulations, it is demonstrated that the proposed channel is undetectable against not only the traditional detection methods but also the latest machine learning based methods. Meanwhile, it maintains a reasonable transmission capacity of 2.25 bits/packet much higher than binary channels.