CUI Xin, YAN Bin, JIA Xia, WANG Ya-fei
(College of Information and Electrical Engineering, Shandong University of Science and Technology, Qingdao 266590, China)
Abstract： Watermarking system based on quantization index modulation (QIM) is increasingly popular in high payload applications, but it is inherently fragile against amplitude scaling attacks. In order to resist desynchronization attacks of QIM digital watermarking, a low density parity check (LDPC) code-aided QIM watermarking algorithm is proposed, and the performance of QIM watermarking system can be improved by incorporating LDPC code with message passing estimation/detection framework. Using the theory of iterative estimation and decoding, the watermark signal is decoded by the proposed algorithm through iterative estimation of amplitude scaling parameters and decoding of watermark. The performance of the proposed algorithm is closer to the dirty paper Shannon limit than that of repetition code aided algorithm when the algorithm is attacked by the additive white Gaussian noise. For constant amplitude scaling attacks, the proposed algorithm can obtain the accurate estimation of amplitude scaling parameters. The simulation result shows that the algorithm can obtain similar performance compared to the algorithm without desynchronization.
Key words： digital watermarking; quantization index modulation (QIM); message passing algorithm based on factor graph; low density parity check (LDPC) code; amplitude scaling attack
CLD number： TP309.2 Document code： A
Article ID： 1674-8042(2014)01-0037-04 doi： 10.3969/j.issn.1674-8042.2014.01.008
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基于 LDPC 编码辅助和消息传递的抗幅度
缩放攻击 QIM 数字水印算法
崔鑫, 颜斌, 贾霞, 王亚菲
(山东科技大学 信息与电气工程学院， 山东 青岛 266590)
摘要:基于量化索引调制(QIM)的数字水印系统， 被越来越广泛地应用于数字水印信号的嵌入和提取， 但是它对于幅度缩放攻击有明显的脆弱性。 本文结合 LDPC 编码辅助和消息传递算法进行水印信号的提取和参数估计， 改善了 QIM 数字水印系统的性能。 对于固定幅度缩放攻击， 本文提出的算法比利用重复码编码辅助的消息传递算法， 更接近于脏纸码代码香农限。
关键词:数字水印； 量化索引调制； 基于因子图的消息传递算法； LDPC 码； 抗幅度缩放攻击
引用格式：CUI Xin, YAN Bin, JIA Xia, et al. QIM digital watermarking based on LDPC code and message passing under scaling attacks. Journal of Measurement Science and Instrumentation, 2014, 5(1): 37-40. [doi: 10.3969/j.issn.1674-8042.2014.01.008]
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