用于电子发票凭据篡改检测与恢复的认证水印算法  

Watermarking Algorithm for Tamper Detection and Recovery of E-Invoice Proof Authentication

作　　者：尹帮旭 陈帆[1] 和红杰[1] YIN Bangxu;CHEN Fan;HE Hongjie(School of Information Science and Technology,Southwest Jiaotong University,Chengdu 610031,Sichuan,China)

机构地区：[1]西南交通大学信息科学与技术学院,四川成都610031

出　　处：《华南理工大学学报（自然科学版）》2018年第5期68-77,共10页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(61872303;61373180);四川省科技厅科技创新人才计划项目(2018RZ0143)~~

摘　　要：综合考虑文件大小、篡改检测性能和恢复质量,提出了一种适用于电子发票凭据真实性认证的GIF图像水印算法.该算法根据电子发票特性将图像块划分为重要块和非重要块两类,对所有图像块结合内容和类型码生成认证水印并嵌入自身的最低有效位,然后对重要块生成变长恢复水印,并基于密钥和重要块比例自适应选择多个非重要块携带水印信息,以使含水印图像的质量和文件大小最优.通过认证水印、类型码和恢复水印三层比较实现了对图像块的真实性认证.图像块分类仅对重要块生成变长恢复水印,能有效降低水印嵌入容量,不仅提高了含水印图像的质量,而且使含水印电子发票的GIF图像文件较小,同时三层比较检测还提高了算法的篡改检测性能.与现有同类认证水印算法相比,文中算法可在不降低篡改检测与恢复性能的基础上,使含水印电子发票图像的GIF文件减小1/2.By taking into consideration the detection performance,recovery quality and file size,this paper proposes an authentication-watermarking algorithm for an e-invoice proof image in GIF format.According to the characteristics of an e-invoice image invoice,all blocks are classified into an important block and an unimportant one.The authentication watermark of each block is generated according to the type code and content itself,and is inserted the least significant bit(LSB)itself.To improve imperceptibility and file-size,the recovery watermark with unfixed length of each important block is generated and is embedded in the many unimportant blocks randomly chosen on the basis of secret key.The validity of an e-invoice image is detected by three-layered detection by means of authentication watermark,type code and recovery watermark.The watermark capacity of the proposed scheme is reduced to about 0.5 bpp(bit per pixel)since the important blocks are used to generate the recovery watermark with unfixed length.The low watermark payload not only improves the quality of watermarked e-invoice image,but also reduces the file size of watermarked GIF image.Furthermore,the tamper detection performance is improved due to the three-layered detection.Compared with the current similar watermarking methods,the watermarked e-invoice image generated by the proposed scheme has a better quality,which means that its file-size is half in comparison with that generated by the current methods,without influence of the tamper detection and recovery performance.

关 键 词：电子发票凭据 认证水印 篡改检测 篡改恢复 文件大小 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]