自适应网络隐蔽信道的研究与实现

Study and Implementation of Self-adaptive Network Covert Channel

传统的被动型时间间隔隐蔽信道的参数一旦确定,该信道的平均转发速率也就确定,这在状况多发的网络中很难正常工作,同时容易暴露。鉴于此,文中提出了一个基于多进制的自适应性被动型时间网络隐蔽信道。该隐蔽信道可根据当前网络状况自发地调整转发速率,以适应网络状况变化,采用可变的多进制来代替固定的二进制编码方案,以提高信息传输速率。实验结果表明,自适应隐蔽信道的信息传输速率是传统隐蔽信道的1.5倍,且能使负载隐蔽信息的负载流更加接近正常数据流,从而具有更强的隐蔽性。

The average forwarding rate of traditional passive covert channel is determined once the time parameters are determined. It is very hard to work well in a complex network and easy to be perceived. A covert timing channe}, known as multi symbol-based self-adapt network covert channel, is proposed. This covert channel could spontaneously adjust the forwarding rate in accordance with the current network state. In addition, by taking utilize dynamical polybinary encoding instead of fixed binary encoding, the information transmission rate could be further improved. The experimental results show that the information transmission of the self-adaptive covert channel is 50 percent over that of traditional type, while this channel causes little abnormity, and thus is of much stronger covertness.