中文摘要：

隐蔽通信是继加密技术之后一门新兴的信息传输安全技术．随着互联网的飞速发展，基于网络协议和流媒体的隐蔽通信技术蓬勃发展．论文提出了一种采用HOOK技术，基于目前流行的互联网即时通信软件实现隐蔽通信的基本框架．重点研究了通过HOOK技术复用流媒体的基本方法，以及具体的实现算法，在网络即时通信（VoIP）软件的基础上，采用HOOK技术实现了一套端到端的隐蔽通信系统．实验结果表明，本文提出的结构可以有效地截获应用软件收发的网络数据，在此基础上，可以有效地发送和接收隐秘信息，实现一类新的隐蔽通信系统．

英文摘要：

Covert communication is a new security technology of information transmission other than the encryption. Along with the rapid development of Internet, the covert communication based on network protocols and streaming media is flourishing. The authors have suggested a basic framework to achieve covert communication using HOOK technology onto popular Internet instant messaging software. The basic approach of reusing the media stream by HOOK technology as well as specific implementation al- gorithm is focused on. An end-to-end covert communication system based on HOOK technology has also been developed which attaches to voice over IP （VolP） software. Experimental results show that the framework suggested in this paper can effectively intercept the network data which is sent or received by the VolP software. Furthermore, it can also exchange covert information, which means that the authors have achieved a new kind of covert communication system.