一种基于像素值偏移编解码技术的屏摄隐通道研究  

A Covert Channel Communication Method Based on Pixel Offset Encoding and Decoding Technique

作　　者：宋宇波 马文豪 胡爱群 王俊波[2,3,4] SONG Yubo;MA Wenhao;HU Aiqun;WANG Junbo(School of Cyber Science and Engineering,Southeast University,Narying 211189,China;Network Communication and Security Purple Mountain Laboratory,Ncuying 211189,China;School of Information Science and Engineering,Southeast University,Nanjing 211189,China;National Mobile Communications Research Laboratory,Southeast University,Nanjing 211189,China)

机构地区：[1]东南大学网络空间安全学院,南京211189 [2]网络通信与安全紫金山实验室,南京211189 [3]东南大学信息科学与工程学院,南京211189 [4]东南大学移动通信国家重点实验室,南京211189

出　　处：《信息网络安全》2021年第4期31-38,共8页Netinfo Security

基　　金：国家自然科学基金[61601113]。

摘　　要：屏摄隐通道通过摄像机拍摄显示器进行隐蔽通信。现有屏摄隐通道技术对摄像机的拍摄角度有严格要求。针对这种情况,文章提出了一种基于像素值偏移编解码技术的屏摄隐通道方法。该方法对显示图像的像素值进行偏移,把二维码(QR码)嵌入显示帧。利用人眼对于对比度、亮度相近的图像分辨能力差的特点,秘密地将显示帧发送给摄像机。在解码时提取加入的偏移量,并且使用透视还原方法,抵消不同拍摄角度的失真,还原出QR码。通过实验验证了文章方法的可行性,实验表明,该方法适合于存在拍摄角度时的图像提取和还原,各角度平均模块误码率在3%以下。Using screen-camera covert channel,covert communication can be realized by shooting the screen.The current implementation of screen-camera covert channel requires a strictlylimited shooting angle for the camera.Given this situation,this paper introduces a screen-camera covert channel method based on pixel offset coding technique.In this method,pixel values of the display frame are offset and embed QR code into the frame.Using the poor ability of the human eye for distinguishing images with similar contrast and brightness,the frames can be sent to the camera secretly.In the decoding process,the offset is extracted,and the perspective restoration method is used to neutralize the interference caused by shooting angles and the QR codeisrestored.QR code is used as the information coding scheme,and pixel value offset coding is used as the transmission coding scheme.This combination combines the high error correction ability of QR code and the strong anti-interference ability of offset coding to realize robust transmission.In this paper,the feasibility of the method is verified by experiments,Experimental results show that this method is suitable for image extraction and restoration in the presence of shooting angle,and the average module error rate is less than 3%.

关 键 词：隐通道 屏幕摄像机通信 气隙系统 数据过滤 图像处理 

分 类 号：TP309[自动化与计算机技术—计算机系统结构]