大容量二维码及水印技术在证件防伪中的应用研究

发布时间：2018-07-03 08:25

本文选题：LSB + QR码　；参考：《延边大学》2017年硕士论文

【摘要】：随着互联网技术的飞速发展,一些文件信息的获取变得十分方便,从而导致一系列利用高科技设备而进行的非法活动,严重的威胁了文件信息的安全。近年来二维码技术被广泛的应用在防伪的领域中,但是由于其编码是开放的,所以防伪性能也不高。此外,由于二维码结构之间的制约,导致其包含的信息容量也不大。数字水印技术是实现数字产品版权保护的有效方法,选择合适的水印算法也可以保护文件信息的安全。因此将数字水印技术与二维码技术结合应用在防伪的领域中,可以提高防伪的性能,对容量较大的文件信息和数字产品进行有力的保护。本学位论文基于二维码编解码的具体分析,设计大容量的二维码来保护大容量文件信息的安全,同时结合数字水印技术,进一步保护文件信息的版权。首先,提出了一种基于大容量长条二维码的编解码算法。该算法通过平衡QR码(QuickR esponse Code)的纠错级别和版本,将容量较大的文件信息编码生成大容量的二维码。此外,为了进一步保护信息的安全,编码生成长条二维码以及对长条二维码解码的特殊扫描器。其次,提出了一种基于长条二维码的LSB(Least Significant Bit)空域水印算法。该算法使用长条二维码图像(RGB图像)作为载体图像,使用MD 5(Message-Digest Algorithm 5)算法对文件信息进行编码,MD5算法结果作为水印信息,通过处理生成三张水印图像。将载体图像分为R、G、B三层,采用LSB空域水印算法将三张水印图像分别分层嵌入。对嵌入水印的R、G、B载体图像应用Arnold变换置乱图像,最后合并置乱后的R、G、B载体图像,完成水印的嵌入。最后,提出了分步式防伪方案,通过比较分层提取出的水印图像和再次应用MD5算法得到的水印图像,实现防伪验证,即实现第一步的防伪方案。通过比对扫描长条二维码的信息和生成长条二维码的文件信息,实现篡改提示功能,即第二步的防伪方案。实验结果表明,本文提出的基于长条二维码的LSB空域水印算法对常见的攻击如剪切、噪声具有较好的抵抗力,说明该算法具有较强的鲁棒性。另外,对载体图像施加本文中LSB空域水印算法抵抗力薄弱的攻击时,对长条二维码载体图像进行特殊扫描,其包含的信息依然能够被清晰的解析出来。通过水印信息是否发生改变提示文件信息是否被篡改,如果检测出文件信息被篡改,篡改提示功能检测文件信息被更改的具体内容和位置,即实现了第二步防伪方案。从而本文提出的分步式防伪验证方案,极大的发挥了分步式防伪的优势。
[Abstract]:With the rapid development of Internet technology, the acquisition of some documents and information becomes very convenient, which leads to a series of illegal activities using high-tech equipment, which seriously threaten the security of document information. In recent years, two-dimensional code technology is widely used in the field of anti-counterfeiting, but its coding is open, so the anti-counterfeiting performance is not high. In addition, due to the constraints between the structure of the two-dimensional code, it contains little information capacity. Digital watermarking technology is an effective method to realize copyright protection of digital products. Choosing the appropriate watermarking algorithm can also protect the security of file information. Therefore, the combination of digital watermarking technology and two-dimensional code technology in the field of anti-counterfeiting, can improve the performance of anti-counterfeiting, large capacity of file information and digital products for effective protection. Based on the analysis of the encoding and decoding of the QR code, this dissertation designs a large capacity QR code to protect the security of the large file information, and combines the digital watermarking technology to further protect the copyright of the file information. Firstly, a coding and decoding algorithm based on large-capacity long-bar two-dimensional code is proposed. By balancing the error correction level and version of QR esponse code, the algorithm encodes the large volume file information to generate the large volume QR code. In addition, in order to further protect the security of information, the code generates long QR codes and a special scanner for decoding long QR codes. Secondly, a LSB (least significant bit) spatial watermarking algorithm based on long bar two dimensional code is proposed. In this algorithm, the long two-dimensional code image (RGB image) is used as the carrier image, the MD5 (Message-Digest Algorithm 5) algorithm is used to encode the file information as watermark information, and three watermark images are generated by processing. The carrier image is divided into three layers, and the LSB spatial watermarking algorithm is used to embed the three watermark images respectively. Arnold transform is applied to the watermark image. Finally, the scrambled image is merged to complete the watermark embedding. Finally, a step by step anti-counterfeiting scheme is proposed. By comparing the watermark image extracted by layers with the watermark image obtained by using MD5 algorithm again, the anti-counterfeiting verification is realized, that is, the first step anti-counterfeiting scheme is realized. By comparing the information of scanning long QR code and generating the file information of long QR code, the tamper prompt function is realized, that is, the second step anti-counterfeiting scheme. Experimental results show that the LSB spatial watermarking algorithm proposed in this paper is robust to common attacks such as shear and noise. In addition, when the carrier image is attacked by the LSB watermarking algorithm in this paper, the information contained in the image can still be analyzed clearly. If the file information is tampered with, the tampering function detects the specific content and position of the file information change, that is, the second step anti-counterfeiting scheme is realized. Thus, the step-by-step anti-counterfeiting verification scheme proposed in this paper greatly exerts the advantage of step-by-step anti-counterfeiting.
【学位授予单位】：延边大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP309.7

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