一种基于闭源流媒体的隐蔽通讯方法

Covert Communication Method Based on Closed Source Streaming Media

隐蔽信道代表无法预见的通信方法,其利用授权的公开通信作为隐蔽消息的载体介质。隐蔽通道可以是一种安全有效的传输隐藏在明显流量中的机密信息的方式。已有的基于流媒体的隐蔽信道往往由于建立起了新的通讯链接而容易被监测到。鉴于此,文中对经过流媒体服务器的数据包进行了针对性的测试和研究,研究发现已有的闭源流媒体不对经过服务器的数据包进行严格检查,并发现数据包在修改部分数据后依然可达终端。基于以上事实,文中通过探究经过服务器修改后的数据包的数据位分布规律,建立了一个基于闭源流媒体的隐蔽通道。为了提高数据包的熵值,使用高效且小巧的speck算法对数据包的内容进行加密。为了实时监测现有链接和实时流量,文中将防火墙串联在网络结构中,并借助防火墙对网络连接和通讯质量进行监测。实验数据表明,所提方法不会增加网络连接的数目,也不会影响通讯质量,而且能够兼容多种流媒体设备,并且表明了所提方法实用且不容易被检测到。不仅如此,由于此隐蔽信道搭载在闭源流媒体上,隐蔽信息的传输效率较高。上述结果表明,基于现有的闭源流媒体软件的通讯流而建立起隐蔽信道的方法是可行的,且该方法在对数据包的内容进行加密后,具有较强的隐蔽性。

A covert channel represents an unforeseen method of communication that utilizes authorized public communication as a carrier medium for covert messages.A covert channel can be a safe and efficient way to transmit confidential information hidden in explicit traffic.Existing streaming- based covert channels are often easily detected due to the establishment of new communication links.For this reason,this paper conducted targeted tests and research on data pa- ckets passing through the streaming media server.It is found that the existing closed source streaming media does not strictly check the data packets passing through the server,and the data packets can still reach the termina lafter modi- fying some data. Based on the above facts,this paper established a hidden channel based on closed source streaming media by exploring the data bit distribution rules of the modified data packets through the server.In order to improve the entropy value of the data packet,this paper used an efficient and compact speck algorithm to encrypt the packet content.In order to monitor existing links and real-time traffic in real time,the firewalls were connected in series in the network structure,and the network connection and communication quality were monitored by a firewall.Experimental data show that this method does not increase the number of network connections and does not affect the communication qua- lity,and it is compatible with a variety of streaming media devices,showing that this method is practical and not easily detected.Moreover,since the hidden channel is mounted on the closed source streaming medium,the transmission efficiency of the covert information is high.The above results show that the method of establishing a covert channel based on the communication flow of the existing closed source streaming media software is feasible,and has strong concealment after encrypting the content of the data packet.